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Greenhalgh T, MacIntyre CR, Baker MG, Bhattacharjee S, Chughtai AA, Fisman D, Kunasekaran M, Kvalsvig A, Lupton D, Oliver M, Tawfiq E, Ungrin M, Vipond J. Masks and respirators for prevention of respiratory infections: a state of the science review. Clin Microbiol Rev 2024; 37:e0012423. [PMID: 38775460 DOI: 10.1128/cmr.00124-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2024] Open
Abstract
SUMMARYThis narrative review and meta-analysis summarizes a broad evidence base on the benefits-and also the practicalities, disbenefits, harms and personal, sociocultural and environmental impacts-of masks and masking. Our synthesis of evidence from over 100 published reviews and selected primary studies, including re-analyzing contested meta-analyses of key clinical trials, produced seven key findings. First, there is strong and consistent evidence for airborne transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and other respiratory pathogens. Second, masks are, if correctly and consistently worn, effective in reducing transmission of respiratory diseases and show a dose-response effect. Third, respirators are significantly more effective than medical or cloth masks. Fourth, mask mandates are, overall, effective in reducing community transmission of respiratory pathogens. Fifth, masks are important sociocultural symbols; non-adherence to masking is sometimes linked to political and ideological beliefs and to widely circulated mis- or disinformation. Sixth, while there is much evidence that masks are not generally harmful to the general population, masking may be relatively contraindicated in individuals with certain medical conditions, who may require exemption. Furthermore, certain groups (notably D/deaf people) are disadvantaged when others are masked. Finally, there are risks to the environment from single-use masks and respirators. We propose an agenda for future research, including improved characterization of the situations in which masking should be recommended or mandated; attention to comfort and acceptability; generalized and disability-focused communication support in settings where masks are worn; and development and testing of novel materials and designs for improved filtration, breathability, and environmental impact.
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Affiliation(s)
- Trisha Greenhalgh
- Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, United Kingdom
| | - C Raina MacIntyre
- Biosecurity Program, The Kirby Institute, University of New South Wales, Sydney, Australia
| | - Michael G Baker
- Department of Public Health, University of Otago, Wellington, New Zealand
| | - Shovon Bhattacharjee
- Biosecurity Program, The Kirby Institute, University of New South Wales, Sydney, Australia
- School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney, Australia
| | - Abrar A Chughtai
- School of Population Health, University of New South Wales, Sydney, Australia
| | - David Fisman
- Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
| | - Mohana Kunasekaran
- Biosecurity Program, The Kirby Institute, University of New South Wales, Sydney, Australia
| | - Amanda Kvalsvig
- Department of Public Health, University of Otago, Wellington, New Zealand
| | - Deborah Lupton
- Centre for Social Research in Health and Social Policy Research Centre, Faculty of Arts, Design and Architecture, University of New South Wales, Sydney, Australia
| | - Matt Oliver
- Professional Standards Advocate, Edmonton, Canada
| | - Essa Tawfiq
- Biosecurity Program, The Kirby Institute, University of New South Wales, Sydney, Australia
| | - Mark Ungrin
- Faculty of Veterinary Medicine; Department of Biomedical Engineering, Schulich School of Engineering; Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
| | - Joe Vipond
- Department of Emergency Medicine, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
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2
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Kadokura K, Kato H, Yoshizumi K, Kamikuri M, Kamenosono A, Shinkawa N, Hamada Y, Kawamura H, Shimada T, Kuroda M, Sunagawa T. Rapid response to a COVID-19 outbreak at a nightclub in Kagoshima prefecture, Japan, in the early phase of the COVID-19 pandemic, June and July 2020: A descriptive epidemiological study. J Infect Chemother 2024:S1341-321X(24)00098-9. [PMID: 38521457 DOI: 10.1016/j.jiac.2024.03.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 02/23/2024] [Accepted: 03/20/2024] [Indexed: 03/25/2024]
Abstract
INTRODUCTION During COVID-19 pandemic in Japan, nightclubs were identified as high-risk locations for COVID-19 outbreaks, but an outbreak investigation in this setting is challenging because of the anonymous and opportunistic nature of interactions. METHODS The joint rapid response team collected epidemiological data, conducted descriptive epidemiology to determine the characteristics of cases associated with the nightclub, and implemented countermeasures. Polymerase chain reaction (PCR) tests were performed by the Local Institute of Public Health, Kagoshima University, and several commercial laboratories. RESULTS Between June 15 and July 20, 2020, 121 individuals tested positive for SARS-CoV-2 (59 confirmed and 62 asymptomatic) of whom 8 were nightclub staff who had no travel history of outside Kagoshima, 66 were guests, and 47 were subsequent contacts. The median age was 32 years (interquartile range: 24-43 years). One individual showed severe symptoms but there were no fatal. The epidemic curve showed one peak on June 30 and July 1 with a limited number of cases subsequently. Of the 121 cases, 116 and 5 were in individuals living in and outside Kagoshima Prefecture, respectively. Haplotype network analysis showed 5 genome-wide single-nucleotide variants between the isolates before and during this outbreak. CONCLUSIONS There is a possibility that unidentified guests from outside Kagoshima Prefecture could infect staff who could subsequently spread the virus to guests and other staff, who were mainly a younger population. The rapid outbreak response enabled onward transmission in the community to be minimized. This outbreak investigation could provide insights for effective responses to challenging situations in future pandemic.
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Affiliation(s)
- Keisuke Kadokura
- Field Epidemiology Training Program, National Institute of Infectious Diseases, Tokyo, Japan; Chiba Prefectural Institute of Public Health, Chiba, Japan
| | - Hirofumi Kato
- Center for Field Epidemic Intelligence, Research and Professional Development, National Institute of Infectious Diseases, Tokyo, Japan.
| | - Kayoko Yoshizumi
- Kagoshima City Public Health and Welfare Bureau, Kagoshima, Japan
| | - Miyuki Kamikuri
- Kagoshima City Public Health and Welfare Bureau, Kagoshima, Japan
| | - Akira Kamenosono
- Kagoshima Prefectural Health Promotion Division, Life, Health and Social Welfare Department, Kagoshima, Japan
| | - Naomi Shinkawa
- Department of Microbiology, Kagoshima Prefectural Institute for Environmental Research and Public Health, Kagoshima, Japan
| | - Yuka Hamada
- Department of Microbiology, Kagoshima Prefectural Institute for Environmental Research and Public Health, Kagoshima, Japan
| | - Hideki Kawamura
- Department of Infection Control and Prevention, Kagoshima University Hospital, Kagoshima, Japan
| | - Tomoe Shimada
- Center for Field Epidemic Intelligence, Research and Professional Development, National Institute of Infectious Diseases, Tokyo, Japan
| | - Makoto Kuroda
- Pathogen Genomics Center, National Institute of Infectious Diseases, Tokyo, Japan
| | - Tomimasa Sunagawa
- Center for Field Epidemic Intelligence, Research and Professional Development, National Institute of Infectious Diseases, Tokyo, Japan.
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3
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Atamer Balkan B, Chang Y, Sparnaaij M, Wouda B, Boschma D, Liu Y, Yuan Y, Daamen W, de Jong MCM, Teberg C, Schachtschneider K, Sikkema RS, van Veen L, Duives D, ten Bosch QA. The multi-dimensional challenges of controlling respiratory virus transmission in indoor spaces: Insights from the linkage of a microscopic pedestrian simulation and SARS-CoV-2 transmission model. PLoS Comput Biol 2024; 20:e1011956. [PMID: 38547311 PMCID: PMC11003685 DOI: 10.1371/journal.pcbi.1011956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 04/09/2024] [Accepted: 02/29/2024] [Indexed: 04/11/2024] Open
Abstract
SARS-CoV-2 transmission in indoor spaces, where most infection events occur, depends on the types and duration of human interactions, among others. Understanding how these human behaviours interface with virus characteristics to drive pathogen transmission and dictate the outcomes of non-pharmaceutical interventions is important for the informed and safe use of indoor spaces. To better understand these complex interactions, we developed the Pedestrian Dynamics-Virus Spread model (PeDViS), an individual-based model that combines pedestrian behaviour models with virus spread models incorporating direct and indirect transmission routes. We explored the relationships between virus exposure and the duration, distance, respiratory behaviour, and environment in which interactions between infected and uninfected individuals took place and compared this to benchmark 'at risk' interactions (1.5 metres for 15 minutes). When considering aerosol transmission, individuals adhering to distancing measures may be at risk due to the buildup of airborne virus in the environment when infected individuals spend prolonged time indoors. In our restaurant case, guests seated at tables near infected individuals were at limited risk of infection but could, particularly in poorly ventilated places, experience risks that surpass that of benchmark interactions. Combining interventions that target different transmission routes can aid in accumulating impact, for instance by combining ventilation with face masks. The impact of such combined interventions depends on the relative importance of transmission routes, which is hard to disentangle and highly context dependent. This uncertainty should be considered when assessing transmission risks upon different types of human interactions in indoor spaces. We illustrated the multi-dimensionality of indoor SARS-CoV-2 transmission that emerges from the interplay of human behaviour and the spread of respiratory viruses. A modelling strategy that incorporates this in risk assessments can help inform policy makers and citizens on the safe use of indoor spaces with varying inter-human interactions.
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Affiliation(s)
- Büsra Atamer Balkan
- Quantitative Veterinary Epidemiology, Wageningen University & Research, Wageningen, The Netherlands
| | - You Chang
- Quantitative Veterinary Epidemiology, Wageningen University & Research, Wageningen, The Netherlands
| | - Martijn Sparnaaij
- Department of Transport & Planning, Delft University of Technology, Delft, The Netherlands
| | - Berend Wouda
- Gamelab, Delft University of Technology, Delft, The Netherlands
| | - Doris Boschma
- Gamelab, Delft University of Technology, Delft, The Netherlands
| | - Yangfan Liu
- Quantitative Veterinary Epidemiology, Wageningen University & Research, Wageningen, The Netherlands
| | - Yufei Yuan
- Department of Transport & Planning, Delft University of Technology, Delft, The Netherlands
| | - Winnie Daamen
- Department of Transport & Planning, Delft University of Technology, Delft, The Netherlands
| | - Mart C. M. de Jong
- Quantitative Veterinary Epidemiology, Wageningen University & Research, Wageningen, The Netherlands
| | - Colin Teberg
- Steady State Scientific Computing, Chicago, Illinois, United States of America
| | | | | | - Linda van Veen
- Gamelab, Delft University of Technology, Delft, The Netherlands
| | - Dorine Duives
- Department of Transport & Planning, Delft University of Technology, Delft, The Netherlands
| | - Quirine A. ten Bosch
- Quantitative Veterinary Epidemiology, Wageningen University & Research, Wageningen, The Netherlands
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4
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Port JR, Morris DH, Riopelle JC, Yinda CK, Avanzato VA, Holbrook MG, Bushmaker T, Schulz JE, Saturday TA, Barbian K, Russell CA, Perry-Gottschalk R, Shaia C, Martens C, Lloyd-Smith JO, Fischer RJ, Munster VJ. Host and viral determinants of airborne transmission of SARS-CoV-2 in the Syrian hamster. eLife 2024; 12:RP87094. [PMID: 38416804 PMCID: PMC10942639 DOI: 10.7554/elife.87094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2024] Open
Abstract
It remains poorly understood how SARS-CoV-2 infection influences the physiological host factors important for aerosol transmission. We assessed breathing pattern, exhaled droplets, and infectious virus after infection with Alpha and Delta variants of concern (VOC) in the Syrian hamster. Both VOCs displayed a confined window of detectable airborne virus (24-48 hr), shorter than compared to oropharyngeal swabs. The loss of airborne shedding was linked to airway constriction resulting in a decrease of fine aerosols (1-10 µm) produced, which are suspected to be the major driver of airborne transmission. Male sex was associated with increased viral replication and virus shedding in the air. Next, we compared the transmission efficiency of both variants and found no significant differences. Transmission efficiency varied mostly among donors, 0-100% (including a superspreading event), and aerosol transmission over multiple chain links was representative of natural heterogeneity of exposure dose and downstream viral kinetics. Co-infection with VOCs only occurred when both viruses were shed by the same donor during an increased exposure timeframe (24-48 hr). This highlights that assessment of host and virus factors resulting in a differential exhaled particle profile is critical for understanding airborne transmission.
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Affiliation(s)
- Julia R Port
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of HealthHamiltonUnited States
| | - Dylan H Morris
- Department of Ecology and Evolutionary Biology, University of California, Los AngelesLos AngelesUnited States
| | - Jade C Riopelle
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of HealthHamiltonUnited States
| | - Claude Kwe Yinda
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of HealthHamiltonUnited States
| | - Victoria A Avanzato
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of HealthHamiltonUnited States
| | - Myndi G Holbrook
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of HealthHamiltonUnited States
| | - Trenton Bushmaker
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of HealthHamiltonUnited States
| | - Jonathan E Schulz
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of HealthHamiltonUnited States
| | - Taylor A Saturday
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of HealthHamiltonUnited States
| | - Kent Barbian
- Rocky Mountain Research and Technologies Branch, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of HealthHamiltonUnited States
| | - Colin A Russell
- Department of Medical Microbiology | Amsterdam University Medical Center, University of AmsterdamAmsterdamNetherlands
| | - Rose Perry-Gottschalk
- Rocky Mountain Visual and Medical Arts Unit, Research Technologies Branch, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of HealthHamiltonUnited States
| | - Carl Shaia
- Rocky Mountain Veterinary Branch, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of HealthHamiltonUnited States
| | - Craig Martens
- Rocky Mountain Research and Technologies Branch, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of HealthHamiltonUnited States
| | - James O Lloyd-Smith
- Department of Ecology and Evolutionary Biology, University of California, Los AngelesLos AngelesUnited States
| | - Robert J Fischer
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of HealthHamiltonUnited States
| | - Vincent J Munster
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of HealthHamiltonUnited States
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5
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Ambalavanan R, Snead RS, Marczika J, Malioukis A. Epidemiological contemplation for a currently pragmatic COVID-19 health passport: a perspective. Front Public Health 2024; 12:1347623. [PMID: 38414904 PMCID: PMC10896918 DOI: 10.3389/fpubh.2024.1347623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 01/23/2024] [Indexed: 02/29/2024] Open
Abstract
The coronavirus disease 2019 (COVID-19) has caused a global pandemic that has wreaked havoc on the lives of millions of people around the world. Confinement measures aim to reduce the epidemic's spread and minimize the burden of morbidity and mortality. In response to the challenges caused by the pandemic, digital health passports have been developed exponentially. We highlight the latent epidemiological barriers to health passports to achieve standardized digital care platforms. This review paper not only highlights the epidemiological barriers but also articulates the possible infrastructure required to make the International Standard for a multi-factor authenticated and validated health passport.
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Affiliation(s)
- Radha Ambalavanan
- Research Department, The Self Research Institute, Broken Arrow, OK, United States
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6
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Kuehl PJ, Dearing J, Werts A, Cox J, Irshad H, Barrett EG, Tucker SN, Langel SN. Design and validation of an exposure system for efficient inter-animal SARS-CoV-2 airborne transmission in Syrian hamsters. Microbiol Spectr 2023; 11:e0471722. [PMID: 37882564 PMCID: PMC10714807 DOI: 10.1128/spectrum.04717-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 09/18/2023] [Indexed: 10/27/2023] Open
Abstract
IMPORTANCE The main route of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission is airborne. However, there are few experimental systems that can assess the airborne transmission dynamics of SARS-CoV-2 in vivo. Here, we designed, built, and characterized a hamster transmission caging and exposure system that allows for efficient SARS-CoV-2 airborne transmission in Syrian hamsters without contributions from fomite or direct contact transmission. We successfully measured SARS-CoV-2 viral RNA in aerosols and demonstrated that SARS-CoV-2 is transmitted efficiently at either a 1:1 or 1:4 infected index to naïve recipient hamster ratio. This is meaningful as a 1:4 infected index to naïve hamster ratio would allow for simultaneous comparisons of various interventions in naïve animals to determine their susceptibility to infection by aerosol transmission of SARS-CoV-2. Our SARS-CoV-2 exposure system allows for testing viral airborne transmission dynamics and transmission-blocking therapeutic strategies against SARS-CoV-2 in Syrian hamsters.
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Affiliation(s)
- Philip J. Kuehl
- Lovelace Biomedical Research Institute, Albuquerque, New Mexico, USA
| | - Justin Dearing
- Lovelace Biomedical Research Institute, Albuquerque, New Mexico, USA
| | - Adam Werts
- Lovelace Biomedical Research Institute, Albuquerque, New Mexico, USA
| | - Jason Cox
- Lovelace Biomedical Research Institute, Albuquerque, New Mexico, USA
| | - Hammad Irshad
- Lovelace Biomedical Research Institute, Albuquerque, New Mexico, USA
| | - Edward G. Barrett
- Lovelace Biomedical Research Institute, Albuquerque, New Mexico, USA
| | | | - Stephanie N. Langel
- Department of Pathology, Center for Global Health and Diseases, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
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7
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Integration von SARS-CoV-2 als Erreger von Infektionen in der endemischen Situation in die Empfehlungen der KRINKO „Infektionsprävention im Rahmen der Pflege und Behandlung von Patienten mit übertragbaren Krankheiten“. Bundesgesundheitsblatt Gesundheitsforschung Gesundheitsschutz 2023; 66:1279-1301. [PMID: 37861707 DOI: 10.1007/s00103-023-03776-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2023]
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8
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Meehan MT, Hughes A, Ragonnet RR, Adekunle AI, Trauer JM, Jayasundara P, McBryde ES, Henderson AS. Replicating superspreader dynamics with compartmental models. Sci Rep 2023; 13:15319. [PMID: 37714942 PMCID: PMC10504364 DOI: 10.1038/s41598-023-42567-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 09/12/2023] [Indexed: 09/17/2023] Open
Abstract
Infectious disease outbreaks often exhibit superspreader dynamics, where most infected people generate no, or few secondary cases, and only a small fraction of individuals are responsible for a large proportion of transmission. Although capturing this heterogeneity is critical for estimating outbreak risk and the effectiveness of group-specific interventions, it is typically neglected in compartmental models of infectious disease transmission-which constitute the most common transmission dynamic modeling framework. In this study we propose different classes of compartmental epidemic models that incorporate transmission heterogeneity, fit them to a number of real outbreak datasets, and benchmark their performance against the canonical superspreader model (i.e., the negative binomial branching process model). We find that properly constructed compartmental models can capably reproduce observed superspreader dynamics and we provide the pathogen-specific parameter settings required to do so. As a consequence, we also show that compartmental models parameterized according to a binary clinical classification have limited support.
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Affiliation(s)
- Michael T Meehan
- Australian Institute of Tropical Health and Medicine, James Cook University, Townsville, 4811, Australia.
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, 4811, Australia.
| | - Angus Hughes
- School of Public Health and Preventive Medicine, Monash University, Melbourne, 3800, Australia
| | - Romain R Ragonnet
- School of Public Health and Preventive Medicine, Monash University, Melbourne, 3800, Australia
| | - Adeshina I Adekunle
- Defence Science and Technology Group, Department of Defence, Melbourne, 3207, Australia
| | - James M Trauer
- School of Public Health and Preventive Medicine, Monash University, Melbourne, 3800, Australia
| | - Pavithra Jayasundara
- School of Public Health and Preventive Medicine, Monash University, Melbourne, 3800, Australia
| | - Emma S McBryde
- Australian Institute of Tropical Health and Medicine, James Cook University, Townsville, 4811, Australia
| | - Alec S Henderson
- Australian Institute of Tropical Health and Medicine, James Cook University, Townsville, 4811, Australia
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9
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Yang J, Sun D, Xia T, Shi S, Suo J, Kuang H, Sun N, Hu H, Zheng Z, Zhou Y, Li X, Chen S, Huang H, Yan Z. Monitoring Prevalence and Persistence of Environmental Contamination by SARS-CoV-2 RNA in a Makeshift Hospital for Asymptomatic and Very Mild COVID-19 Patients. Int J Public Health 2023; 68:1605994. [PMID: 37767017 PMCID: PMC10520216 DOI: 10.3389/ijph.2023.1605994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Accepted: 08/29/2023] [Indexed: 09/29/2023] Open
Abstract
Objective: To investigate the details of environmental contamination status by SARS-CoV-2 in a makeshift COVID-19 hospital. Methods: Environmental samples were collected from a makeshift hospital. The extent of contamination was assessed by quantitative reverse transcription polymerase chain reaction (RT-qPCR) for SARS-CoV-2 RNA from various samples. Results: There was a wide range of total collected samples contaminated with SARS-CoV-2 RNA, ranging from 8.47% to 100%. Results revealed that 70.00% of sewage from the bathroom and 48.19% of air samples were positive. The highest rate of contamination was found from the no-touch surfaces (73.07%) and the lowest from frequently touched surfaces (33.40%). The most contaminated objects were the top surfaces of patient cubic partitions (100%). The median Ct values among strongly positive samples were 33.38 (IQR, 31.69-35.07) and 33.24 (IQR, 31.33-34.34) for ORF1ab and N genes, respectively. SARS-CoV-2 relic RNA can be detected on indoor surfaces for up to 20 days. Conclusion: The findings show a higher prevalence and persistence in detecting the presence of SARS-CoV-2 in the makeshift COVID-19 hospital setting. The contamination mode of droplet deposition may be more common than contaminated touches.
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Affiliation(s)
- Jinyan Yang
- Department of Disease Prevention and Control, Hainan Hospital of People’s Liberation Army of China General Hospital, Sanya, China
| | - Dan Sun
- Department of Disease Prevention and Control, Hainan Hospital of People’s Liberation Army of China General Hospital, Sanya, China
| | - Tingting Xia
- Department of Disease Prevention and Control, Hainan Hospital of People’s Liberation Army of China General Hospital, Sanya, China
| | - Shi Shi
- Department of Disease Prevention and Control, Hainan Hospital of People’s Liberation Army of China General Hospital, Sanya, China
| | - Jijiang Suo
- Department of Disease Prevention and Control, Hainan Hospital of People’s Liberation Army of China General Hospital, Sanya, China
| | - Huihui Kuang
- Department of Laboratory Medicine, Hainan Hospital of People’s Liberation Army of China General Hospital, Sanya, China
| | - Nana Sun
- Department of Laboratory Medicine, Hainan Hospital of People’s Liberation Army of China General Hospital, Sanya, China
| | - Hongyan Hu
- Department of Laboratory Medicine, Hainan Hospital of People’s Liberation Army of China General Hospital, Sanya, China
| | - Zhecheng Zheng
- Department of Health Economics Management, Hainan Hospital of People’s Liberation Army of China General Hospital, Sanya, China
| | - Yang Zhou
- Department of Health Economics Management, Hainan Hospital of People’s Liberation Army of China General Hospital, Sanya, China
| | - Xiaocui Li
- Department of Cardiology, Hainan Hospital of People’s Liberation Army of China General Hospital, Sanya, China
| | - Shaojuan Chen
- Department of Cardiology, Hainan Hospital of People’s Liberation Army of China General Hospital, Sanya, China
| | - Haiqiang Huang
- Department of Radiotherapy, Hainan Hospital of People’s Liberation Army of China General Hospital, Sanya, China
| | - Zhongqiang Yan
- Department of Disease Prevention and Control, The Second Medical Center of People’s Liberation Army of China General Hospital, Beijing, China
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10
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Molina Grané C, Mancuso P, Vicentini M, Venturelli F, Djuric O, Manica M, Guzzetta G, Marziano V, Zardini A, d'Andrea V, Trentini F, Bisaccia E, Larosa E, Cilloni S, Cassinadri MT, Pezzotti P, Ajelli M, Rossi PG, Merler S, Poletti P. SARS-CoV-2 transmission patterns in educational settings during the Alpha wave in Reggio-Emilia, Italy. Epidemics 2023; 44:100712. [PMID: 37567090 DOI: 10.1016/j.epidem.2023.100712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 07/17/2023] [Accepted: 07/31/2023] [Indexed: 08/13/2023] Open
Abstract
Different monitoring and control policies have been implemented in schools to minimize the spread of SARS-CoV-2. Transmission in schools has been hard to quantify due to the large proportion of asymptomatic carriers in young individuals. We applied a Bayesian approach to reconstruct the transmission chains between 284 SARS-CoV-2 infections ascertained during 87 school outbreak investigations conducted between March and April 2021 in Italy. Under the policy of reactive quarantines, we found that 42.5% (95%CrI: 29.5-54.3%) of infections among school attendees were caused by school contacts. The mean number of secondary cases infected at school by a positive individual during in-person education was estimated to be 0.33 (95%CrI: 0.23-0.43), with marked heterogeneity across individuals. Specifically, we estimated that only 26.0% (95%CrI: 17.6-34.1%) of students and school personnel who tested positive during in-person education caused at least one secondary infection at school. Positive individuals who attended school for at least 6 days before being isolated or quarantined infected on average 0.49 (95%CrI: 0.14-0.83) secondary cases. Our findings provide quantitative insights on the contribution of school transmission to the spread of SARS-CoV-2 in young individuals. Identifying positive cases within 5 days after exposure to their infector could reduce onward transmission at school by at least 30%.
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Affiliation(s)
- Carla Molina Grané
- Center for Health Emergencies, Bruno Kessler Foundation, Trento, Italy; Department of Mathematics, University of Trento, Trento, Italy
| | - Pamela Mancuso
- Epidemiology Unit, Azienda Unità Sanitaria Locale - IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | - Massimo Vicentini
- Epidemiology Unit, Azienda Unità Sanitaria Locale - IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | - Francesco Venturelli
- Epidemiology Unit, Azienda Unità Sanitaria Locale - IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | - Olivera Djuric
- Epidemiology Unit, Azienda Unità Sanitaria Locale - IRCCS di Reggio Emilia, Reggio Emilia, Italy; Department of Biomedical, Metabolic and Neural Sciences, Centre for Environmental, Nutritional and Genetic Epidemiology (CREAGEN), Public Health Unit, University of Modena and Reggio Emilia, Reggio Emilia, Italy
| | - Mattia Manica
- Center for Health Emergencies, Bruno Kessler Foundation, Trento, Italy
| | - Giorgio Guzzetta
- Center for Health Emergencies, Bruno Kessler Foundation, Trento, Italy
| | | | - Agnese Zardini
- Center for Health Emergencies, Bruno Kessler Foundation, Trento, Italy
| | - Valeria d'Andrea
- Center for Health Emergencies, Bruno Kessler Foundation, Trento, Italy
| | - Filippo Trentini
- Center for Health Emergencies, Bruno Kessler Foundation, Trento, Italy; Dondena Centre for Research on Social Dynamics and Public Policy, Bocconi University, Milan, Italy
| | - Eufemia Bisaccia
- Public Health Unit, Azienda Unità Sanitaria Locale - IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | - Elisabetta Larosa
- Public Health Unit, Azienda Unità Sanitaria Locale - IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | - Silvia Cilloni
- Public Health Unit, Azienda Unità Sanitaria Locale - IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | - Maria Teresa Cassinadri
- Public Health Unit, Azienda Unità Sanitaria Locale - IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | - Patrizio Pezzotti
- Department of Infectious Diseases, Istituto Superiore di Sanità, Rome, Italy
| | - Marco Ajelli
- Laboratory for Computational Epidemiology and Public Health, Department of Epidemiology and Biostatistics, Indiana University School of Public Health, Bloomington, IN, USA
| | - Paolo Giorgi Rossi
- Epidemiology Unit, Azienda Unità Sanitaria Locale - IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | - Stefano Merler
- Center for Health Emergencies, Bruno Kessler Foundation, Trento, Italy
| | - Piero Poletti
- Center for Health Emergencies, Bruno Kessler Foundation, Trento, Italy.
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11
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Anderson TL, Nande A, Merenstein C, Raynor B, Oommen A, Kelly BJ, Levy MZ, Hill AL. Quantifying individual-level heterogeneity in infectiousness and susceptibility through household studies. Epidemics 2023; 44:100710. [PMID: 37556994 PMCID: PMC10594662 DOI: 10.1016/j.epidem.2023.100710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 03/17/2023] [Accepted: 07/18/2023] [Indexed: 08/11/2023] Open
Abstract
The spread of SARS-CoV-2, like that of many other pathogens, is governed by heterogeneity. "Superspreading," or "over-dispersion," is an important factor in transmission, yet it is hard to quantify. Estimates from contact tracing data are prone to potential biases due to the increased likelihood of detecting large clusters of cases, and may reflect variation in contact behavior more than biological heterogeneity. In contrast, the average number of secondary infections per contact is routinely estimated from household surveys, and these studies can minimize biases by testing all members of a household. However, the models used to analyze household transmission data typically assume that infectiousness and susceptibility are the same for all individuals or vary only with predetermined traits such as age. Here we develop and apply a combined forward simulation and inference method to quantify the degree of inter-individual variation in both infectiousness and susceptibility from observations of the distribution of infections in household surveys. First, analyzing simulated data, we show our method can reliably ascertain the presence, type, and amount of these heterogeneities given data from a sufficiently large sample of households. We then analyze a collection of household studies of COVID-19 from diverse settings around the world, and find strong evidence for large heterogeneity in both the infectiousness and susceptibility of individuals. Our results also provide a framework to improve the design of studies to evaluate household interventions in the presence of realistic heterogeneity between individuals.
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Affiliation(s)
- Thayer L Anderson
- Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD 21218, United States of America
| | - Anjalika Nande
- Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD 21218, United States of America
| | - Carter Merenstein
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States of America
| | - Brinkley Raynor
- Department of Biostatistics, Epidemiology, & Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States of America
| | - Anisha Oommen
- Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD 21218, United States of America; Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218, United States of America
| | - Brendan J Kelly
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States of America; Department of Biostatistics, Epidemiology, & Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States of America; Division of Infectious Diseases, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States of America
| | - Michael Z Levy
- Department of Biostatistics, Epidemiology, & Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States of America
| | - Alison L Hill
- Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD 21218, United States of America; Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218, United States of America.
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12
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Boterman W. Population density and SARS-CoV-2 pandemic: Comparing the geography of different waves in the Netherlands. URBAN STUDIES (EDINBURGH, SCOTLAND) 2023; 60:1377-1402. [PMID: 37273494 PMCID: PMC10230295 DOI: 10.1177/00420980221087165] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The COVID-19 pandemic has boosted public and scholarly debate about the relationship between infectious disease and the urban. Cities are considered contagious because they are hubs in (inter)national networks and contain high densities of people. However, the role of the urban and population density in the spread of pathogens is complex and is mediated by the wider bio-social environment. This paper analyses the role of population density in the outbreak of COVID-19 in the densely and highly urbanised context of the Netherlands. It compares the geography of the different phases in the epidemic and assesses when and where density plays a role. Using municipal data on the rate of infections and hospitalisations, this paper reveals that spatial patterns differ substantially in time, which does not appear to be simple diffusion. Using panel regressions, it is demonstrated that population density plays a role in those stages in which containment and mitigation measures were least strict, while in periods of lockdown other factors such as household size are associated with higher infection rates. It concludes that lockdowns may have greater effect in urban areas as key urban elements are temporarily cancelled out.
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13
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Khawaja F, Srinivasan K, Spallone A, Feldman A, Cantu S, Ariza-Heredia E, Dvordak T, Alousi A, Ahmed S, George M, Frenzel E, Bhatti M, Chemaly RF. Nosocomial COVID-19 at a comprehensive cancer center during the first year of the pandemic: Lessons learned. Am J Infect Control 2023; 51:506-513. [PMID: 35901993 PMCID: PMC9310434 DOI: 10.1016/j.ajic.2022.07.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 07/19/2022] [Accepted: 07/20/2022] [Indexed: 12/15/2022]
Abstract
BACKGROUND The spread of coronavirus disease 2019 (COVID-19) in health care settings endangers patients with cancer. As knowledge of the transmission of COVID-19 emerged, strategies for preventing nosocomial COVID-19 were updated. We describe our early experience with nosocomial respiratory viral infections (RVIs) at a cancer center in the first year of the pandemic (March 2020-March 2021). METHODS Nosocomial RVIs were identified through our infection control prospective surveillance program, which conducted epidemiologic investigations of all microbiologically documented RVIs. Data was presented as frequencies and percentages or medians and ranges. RESULTS A total of 35 of 3944 (0.9%) documented RVIs were determined to have been nosocomial acquired. Majority of RVIs were due to SARS CoV-2 (13/35; 37%) or by rhinovirus/enterovirus (12/35; 34%). A cluster investigation of the first 3 patients with nosocomial COVID-19 determined that transmission most likely occurred from employees to patients. Five patients (38%) required mechanical ventilation and 4 (31%) died during the same hospital encounter. CONCLUSIONS Our investigation of the cluster led to enhancement of our infection control measures. The implications of COVID-19 vaccination on infection control policies is still unclear and further studies are needed to delineate its impact on the transmission of COVID-19 in a hospital setting.
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Affiliation(s)
- Fareed Khawaja
- Department of Infectious Diseases, Infection Control and Employee Health, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Krithika Srinivasan
- Department of Infectious Diseases, Infection Control and Employee Health, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Amy Spallone
- Department of Infectious Diseases, Infection Control and Employee Health, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Adina Feldman
- Department of Infectious Diseases, Infection Control and Employee Health, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Sherry Cantu
- Department of Infectious Diseases, Infection Control and Employee Health, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Ella Ariza-Heredia
- Department of Infectious Diseases, Infection Control and Employee Health, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Tanya Dvordak
- Department of Infectious Diseases, Infection Control and Employee Health, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Amin Alousi
- Department of Stem Cell Transplantation, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Sairah Ahmed
- Department of Lymphoma and Myeloma, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Marina George
- Office of Chief Operating Officer, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Elizabeth Frenzel
- Department of Infectious Diseases, Infection Control and Employee Health, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Micah Bhatti
- Department of Laboratory Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Roy F Chemaly
- Department of Infectious Diseases, Infection Control and Employee Health, The University of Texas MD Anderson Cancer Center, Houston, TX; Office of Chief Operating Officer, The University of Texas MD Anderson Cancer Center, Houston, TX.
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14
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Schijven JF, Wind M, Todt D, Howes J, Tamele B, Steinmann E. Risk assessment of banknotes as a fomite of SARS-CoV-2 in cash payment transactions. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2023; 43:700-708. [PMID: 35491413 PMCID: PMC9347741 DOI: 10.1111/risa.13935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The COVID 19 pandemic has triggered concerns and assumptions globally about transmission of the SARS-CoV-2 virus via cash transactions. This paper assesses the risk of contracting COVID-19 through exposure to SARS-CoV-2 via cash acting as a fomite in payment transactions. A quantitative microbial risk assessment was conducted for a scenario assuming an infectious person at the onset of symptoms, when virion concentrations in coughed droplets are at their highest. This person then contaminates a banknote by coughing on it and immediately hands it over to another person, who might then be infected by transferring the virions with a finger from the contaminated banknote to a facial mucous membrane. The scenario considered transfer efficiency of virions on the banknote to fingertips when droplets were still wet and after having dried up and subsequently being touched by finger printing or rubbing the object. Accounting for the likelihood of the scenario to occur by considering (1) a local prevalence of 100 COVID-19 cases/100,000 persons, (2) a maximum of about one-fifth of infected persons transmit high virus loads, and (3) the numbers of cash transactions/person/day, the risk of contracting COVID-19 via person-to-person cash transactions was estimated to be much lower than once per 39,000 days (107 years) for a single person. In the general populace, there will be a maximum of 2.6 expected cases/100,000 persons/day. The risk for a cashier at an average point of sale was estimated to be much less than once per 430 working days (21 months). The depicted scenario is a rare event, therefore, for a single person, the risk of contracting COVID-19 via person-to-person cash transactions is very low. At a point of sale, the risk to the cashier proportionally increases but it is still low.
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Affiliation(s)
- Jack F. Schijven
- Centre for Infectious Disease ControlNational Institute for Public Health and the Environment (RIVM)BilthovenThe Netherlands
- Department of Earth SciencesUtrecht UniversityUtrechtThe Netherlands
| | - Mark Wind
- Cash Policy DepartmentDe Nederlandsche BankAmsterdamThe Netherlands
| | - Daniel Todt
- Department of Molecular & Medical VirologyRuhr University BochumBochumGermany
- European Virus Bioinformatics Centre (EVBC)JenaGermany
| | - John Howes
- European Central Bank (ECB)Frankfurt am MainGermany
| | | | - Eike Steinmann
- Department of Molecular & Medical VirologyRuhr University BochumBochumGermany
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15
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Tsang TK, Huang X, Wang C, Chen S, Yang B, Cauchemez S, Cowling BJ. The effect of variation of individual infectiousness on SARS-CoV-2 transmission in households. eLife 2023; 12:82611. [PMID: 36880191 PMCID: PMC9991055 DOI: 10.7554/elife.82611] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 02/20/2023] [Indexed: 02/25/2023] Open
Abstract
Quantifying variation of individual infectiousness is critical to inform disease control. Previous studies reported substantial heterogeneity in transmission of many infectious diseases including SARS-CoV-2. However, those results are difficult to interpret since the number of contacts is rarely considered in such approaches. Here, we analyze data from 17 SARS-CoV-2 household transmission studies conducted in periods dominated by ancestral strains, in which the number of contacts was known. By fitting individual-based household transmission models to these data, accounting for number of contacts and baseline transmission probabilities, the pooled estimate suggests that the 20% most infectious cases have 3.1-fold (95% confidence interval: 2.2- to 4.2-fold) higher infectiousness than average cases, which is consistent with the observed heterogeneity in viral shedding. Household data can inform the estimation of transmission heterogeneity, which is important for epidemic management.
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Affiliation(s)
- Tim K Tsang
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong KongHong KongChina
- Laboratory of Data Discovery for HealthHong KongChina
| | - Xiaotong Huang
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong KongHong KongChina
| | - Can Wang
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong KongHong KongChina
| | - Sijie Chen
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong KongHong KongChina
| | - Bingyi Yang
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong KongHong KongChina
| | - Simon Cauchemez
- Mathematical Modelling of Infectious Diseases Unit, Institut PasteurParisFrance
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16
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Abstract
SARS-CoV-2 viral load and detection of infectious virus in the respiratory tract are the two key parameters for estimating infectiousness. As shedding of infectious virus is required for onward transmission, understanding shedding characteristics is relevant for public health interventions. Viral shedding is influenced by biological characteristics of the virus, host factors and pre-existing immunity (previous infection or vaccination) of the infected individual. Although the process of human-to-human transmission is multifactorial, viral load substantially contributed to human-to-human transmission, with higher viral load posing a greater risk for onward transmission. Emerging SARS-CoV-2 variants of concern have further complicated the picture of virus shedding. As underlying immunity in the population through previous infection, vaccination or a combination of both has rapidly increased on a global scale after almost 3 years of the pandemic, viral shedding patterns have become more distinct from those of ancestral SARS-CoV-2. Understanding the factors and mechanisms that influence infectious virus shedding and the period during which individuals infected with SARS-CoV-2 are contagious is crucial to guide public health measures and limit transmission. Furthermore, diagnostic tools to demonstrate the presence of infectious virus from routine diagnostic specimens are needed.
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Affiliation(s)
- Olha Puhach
- Department of Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Benjamin Meyer
- Centre for Vaccinology, Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland
| | - Isabella Eckerle
- Department of Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland.
- Geneva Centre for Emerging Viral Diseases, Geneva University Hospitals, Geneva, Switzerland.
- Division of Infectious Diseases, Geneva University Hospitals, Geneva, Switzerland.
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17
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Mezhibovsky E, Hoang SH, Szeto S, Roopchand DE. In silico analysis of dietary polyphenols and their gut microbial metabolites suggest inhibition of SARS-CoV-2 infection, replication, and host inflammatory mediators. J Biomol Struct Dyn 2023; 41:14339-14357. [PMID: 36803516 PMCID: PMC10439978 DOI: 10.1080/07391102.2023.2180669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 02/09/2023] [Indexed: 02/22/2023]
Abstract
The outcome of SARS-CoV-2 infection ranges from asymptomatic to severe COVID-19 and death resulting from an exaggerated immune response termed cytokine storm. Epidemiological data have associated consumption of a high-quality plant-based diet with decreased incidence and severity of COVID-19. Dietary polyphenols and their microbial metabolites (MMs) have anti-viral and anti-inflammatory activities. Autodock Vina and Yasara were used in molecular docking and dynamics studies to investigate potential interactions of 7 parent polyphenols (PPs) and 11 MMs with the α- and Omicron variants of the SARS-CoV-2 spike glycoprotein (SGP), papain-like pro-tease (PLpro) and 3 chymotrypsin-like protease (3CLpro), as well as host inflammatory mediators including complement component 5a (C5a), C5a receptor (C5aR), and C-C chemokine receptor type 5 (CCR5). PPs and MMs interacted to varying degrees with residues on target viral and host inflammatory proteins showing potential as competitive inhibitors. Based on these in silico findings, PPs and MMs may inhibit SARS-CoV-2 infection, replication, and/or modulate host immunity in the gut or periphery. Such inhibition may explain why people that consume a high-quality plant-based diet have less incidence and severity of COVID-19.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Esther Mezhibovsky
- Department of Food Science, Rutgers University, NJ Institute for Food, Nutrition and Health (Rutgers Center for Lipid Research and Center for Nutrition, Microbiome, and Health), 61 Dudley Rd., New Brunswick, NJ 08901 USA
- Department of Nutritional Sciences Graduate Program, Rutgers University
| | - Skyler H. Hoang
- Department of Food Science, Rutgers University, NJ Institute for Food, Nutrition and Health (Rutgers Center for Lipid Research and Center for Nutrition, Microbiome, and Health), 61 Dudley Rd., New Brunswick, NJ 08901 USA
| | - Samantha Szeto
- Department of Food Science, Rutgers University, NJ Institute for Food, Nutrition and Health (Rutgers Center for Lipid Research and Center for Nutrition, Microbiome, and Health), 61 Dudley Rd., New Brunswick, NJ 08901 USA
| | - Diana E. Roopchand
- Department of Food Science, Rutgers University, NJ Institute for Food, Nutrition and Health (Rutgers Center for Lipid Research and Center for Nutrition, Microbiome, and Health), 61 Dudley Rd., New Brunswick, NJ 08901 USA
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18
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Pan D, Williams CM, Decker J, Fletcher E, Sze S, Assadi S, Haigh R, Saleem B, Nazareth J, Garton NJ, Pareek M, Barer MR. Exhaled SARS-CoV-2 RNA viral load kinetics measured by facemask sampling associates with household transmission. Clin Microbiol Infect 2023; 29:254.e1-254.e6. [PMID: 35843566 PMCID: PMC9281452 DOI: 10.1016/j.cmi.2022.07.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 06/06/2022] [Accepted: 07/07/2022] [Indexed: 02/07/2023]
Abstract
OBJECTIVES No studies have examined longitudinal patterns of naturally exhaled SARS-CoV-2 RNA viral load (VL) during acute infection. We report this using facemask sampling (FMS) and assessed the relationship between emitted RNA VL and household transmission. METHODS Between December 2020 and February 2021, we recruited participants within 24 hours of a positive RT-qPCR on upper respiratory tract sampling (URTS) (day 0). Participants gave FMS (for 1 hour) and URTS (self-taken) on seven occasions up to day 21. Samples were analysed by RT-qPCR (from sampling matrix strips within the mask) and symptom diaries were recorded. Household transmission was assessed through reporting of positive URTS RT-qPCR in household contacts. RESULTS Analysis of 203 FMS and 190 URTS from 34 participants showed that RNA VL peaked within the first 5 days following sampling. Concomitant URTS, FMS RNA VL, and symptom scores, however, were poorly correlated, but a higher severity of reported symptoms was associated with FMS positivity up to day 5. Of 28 participants who had household contacts, 12 (43%) reported transmission. Frequency of household transmission was associated with the highest (peak) FMS RNA VL obtained (negative genome copies/strip: 0% household transmission; 1 to 1000 copies/strip: 20%; 1001 to 10 000 copies/strip: 57%; >10 000 copies/strip: 75%; p = 0.048; age adjusted OR of household transmission per log increase in copies/strip: 4.97; 95% CI, 1.20-20.55; p = 0.02) but not observed with peak URTS RNA VL. DISCUSSION Exhaled RNA VL measured by FMS is highest in early infection, can be positive in symptomatic patients with concomitantly negative URTS, and is strongly associated with household transmission.
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Affiliation(s)
- Daniel Pan
- Department of Respiratory Sciences, University of Leicester, Leicester, UK; Department of Infectious Diseases and HIV Medicine, University Hospitals of Leicester NHS Trust, Leicester, UK; Li Ka Shing Center for Health Information and Discovery, Oxford Big Data Institute, University of Oxford, UK.
| | - Caroline M Williams
- Department of Respiratory Sciences, University of Leicester, Leicester, UK; Department of Clinical Microbiology, University Hospitals of Leicester NHS Trust, Leicester, UK
| | - Jonathan Decker
- Department of Respiratory Sciences, University of Leicester, Leicester, UK
| | - Eve Fletcher
- Department of Respiratory Sciences, University of Leicester, Leicester, UK
| | - Shirley Sze
- Department of Cardiovascular Sciences, University Hospitals of Leicester NHS Trust, Leicester, UK
| | - Sara Assadi
- Department of Infectious Diseases and HIV Medicine, University Hospitals of Leicester NHS Trust, Leicester, UK
| | - Richard Haigh
- Department of Respiratory Sciences, University of Leicester, Leicester, UK
| | - Baber Saleem
- Department of Engineering, University of Leicester, Leicester, UK
| | - Joshua Nazareth
- Department of Respiratory Sciences, University of Leicester, Leicester, UK; Department of Infectious Diseases and HIV Medicine, University Hospitals of Leicester NHS Trust, Leicester, UK
| | - Natalie J Garton
- Department of Respiratory Sciences, University of Leicester, Leicester, UK
| | - Manish Pareek
- Department of Respiratory Sciences, University of Leicester, Leicester, UK; Department of Infectious Diseases and HIV Medicine, University Hospitals of Leicester NHS Trust, Leicester, UK
| | - Michael R Barer
- Department of Respiratory Sciences, University of Leicester, Leicester, UK; Department of Clinical Microbiology, University Hospitals of Leicester NHS Trust, Leicester, UK
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19
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Imamura T, Watanabe A, Serizawa Y, Nakashita M, Saito M, Okada M, Ogawa A, Tabei Y, Soumura Y, Nadaoka Y, Nakatsubo N, Chiba T, Sadamasu K, Yoshimura K, Noda Y, Iwashita Y, Ishimaru Y, Seki N, Otani K, Imamura T, Griffith MM, DeToy K, Suzuki M, Yoshida M, Tanaka A, Yauchi M, Shimada T, Oshitani H. Transmission of COVID-19 in Nightlife, Household, and Health Care Settings in Tokyo, Japan, in 2020. JAMA Netw Open 2023; 6:e230589. [PMID: 36826818 PMCID: PMC9958531 DOI: 10.1001/jamanetworkopen.2023.0589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/25/2023] Open
Abstract
IMPORTANCE There have been few studies on the heterogeneous interconnection of COVID-19 outbreaks occurring in different social settings using robust, surveillance epidemiological data. OBJECTIVES To describe the characteristics of COVID-19 transmission within different social settings and to evaluate settings associated with onward transmission to other settings. DESIGN, SETTING, AND PARTICIPANTS This is a case series study of laboratory-confirmed COVID-19 cases in Tokyo between January 23 and December 5, 2020, when vaccination was not yet implemented. Using epidemiological investigation data collected by public health centers, epidemiological links were identified and classified into 7 transmission settings: imported, nightlife, dining, workplace, household, health care, and other. MAIN OUTCOMES AND MEASURES The number of cases per setting and the likelihood of generating onward transmissions were compared between different transmission settings. RESULTS Of the 44 054 confirmed COVID-19 cases in this study, 25 241 (57.3%) were among male patients, and the median (IQR) age of patients was 36 (26-52) years. Transmission settings were identified in 13 122 cases, including 6768 household, 2733 health care, and 1174 nightlife cases. More than 6600 transmission settings were detected, and nightlife (72 of 380 [18.9%]; P < .001) and health care (119 [36.2%]; P < .001) settings were more likely to involve 5 or more cases than dining, workplace, household, and other settings. Nightlife cases appeared in the earlier phase of the epidemic, while household and health care cases appeared later. After adjustment for transmission setting, sex, age group, presence of symptoms, and wave, household and health care cases were less likely to generate onward transmission compared with nightlife cases (household: adjusted odds ratio, 0.03; 95% CI, 0.02-0.05; health care: adjusted odds ratio, 0.57; 95% CI, 0.41-0.79). Household settings were associated with intergenerational transmission, while nonhousehold settings mainly comprised transmission between the same age group. Among 30 932 cases without identified transmission settings, cases with a history of visiting nightlife establishments were more likely to generate onward transmission to nonhousehold settings (adjusted odds ratio, 5.30 [95% CI, 4.64-6.05]; P < .001) than those without such history. CONCLUSIONS AND RELEVANCE In this case series study, COVID-19 cases identified in nightlife settings were associated with a higher likelihood of spreading COVID-19 than household and health care cases. Surveillance and interventions targeting nightlife settings should be prioritized to disrupt COVID-19 transmission, especially in the early stage of an epidemic.
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Affiliation(s)
- Takeaki Imamura
- Department of Virology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | | | | | | | - Mayuko Saito
- Department of Virology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Mayu Okada
- Tokyo Metropolitan Institute of Public Health, Tokyo, Japan
| | - Asamoe Ogawa
- Tokyo Metropolitan Institute of Public Health, Tokyo, Japan
| | - Yukiko Tabei
- Tokyo Metropolitan Institute of Public Health, Tokyo, Japan
| | | | - Yoko Nadaoka
- Tokyo Metropolitan Institute of Public Health, Tokyo, Japan
| | - Naoki Nakatsubo
- Public Health and Disease Prevention Division, Suginami City Public Health Center, Tokyo, Japan
| | - Takashi Chiba
- Tokyo Metropolitan Institute of Public Health, Tokyo, Japan
| | - Kenji Sadamasu
- Tokyo Metropolitan Institute of Public Health, Tokyo, Japan
| | | | - Yoshihiro Noda
- Department of Plastic, Reconstructive and Aesthetic Surgery, Nippon Medical School, Tokyo, Japan
| | | | - Yuji Ishimaru
- Bureau of Social Welfare and Public Health, Tokyo Metropolitan Government, Tokyo, Japan
| | - Naomi Seki
- Ota City Public Health Center, Tokyo, Japan
| | - Kanako Otani
- National Institute of Infectious Diseases, Tokyo, Japan
| | | | - Matthew Myers Griffith
- National Centre for Epidemiology and Population Health, the Australian National University, Canberra, Australia
| | - Kelly DeToy
- Division of Global Disease Epidemiology and Control, Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Motoi Suzuki
- National Institute of Infectious Diseases, Tokyo, Japan
| | | | - Atsuko Tanaka
- Bureau of Social Welfare and Public Health, Tokyo Metropolitan Government, Tokyo, Japan
| | | | - Tomoe Shimada
- National Institute of Infectious Diseases, Tokyo, Japan
| | - Hitoshi Oshitani
- Department of Virology, Tohoku University Graduate School of Medicine, Sendai, Japan
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20
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Wang AB, Zhang X, Gao LJ, Zhang T, Xu HJ, Bi YJ. A Review of Filtration Performance of Protective Masks. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:2346. [PMID: 36767714 PMCID: PMC9915213 DOI: 10.3390/ijerph20032346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 01/20/2023] [Accepted: 01/25/2023] [Indexed: 06/18/2023]
Abstract
Masks are essential and effective small protective devices used to protect the general public against infections such as COVID-19. However, available systematic reviews and summaries on the filtration performance of masks are lacking. Therefore, in order to investigate the filtration performance of masks, filtration mechanisms, mask characteristics, and the relationships between influencing factors and protective performance were first analyzed through mask evaluations. The summary of filtration mechanisms and mask characteristics provides readers with a clear and easy-to-understand theoretical cognition. Then, a detailed analysis of influencing factors and the relationships between the influencing factors and filtration performance is presented in. The influence of the aerosol size and type on filtration performance is nonlinear and nonconstant, and filtration efficiency decreases with an increase in the gas flow rate; moreover, fitness plays a decisive role in the protective effects of masks. It is recommended that the public should wear surgical masks to prevent COVID-19 infection in low-risk and non-densely populated areas. Future research should focus on fitness tests, and the formulation of standards should also be accelerated. This paper provides a systematic review that will be helpful for the design of masks and public health in the future.
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Affiliation(s)
- Ao-Bing Wang
- Hebei Key Laboratory of Man-machine Environmental Thermal Control Technology and Equipment, Filtration Performance and Environmental Health of Protective Materials, Xingtai 054000, China
- Advanced Research Center of Thermal and New Energy Technologies, Hebei Vocational University of Technology and Engineering, Xingtai 054000, China
| | - Xin Zhang
- Hebei Key Laboratory of Man-machine Environmental Thermal Control Technology and Equipment, Filtration Performance and Environmental Health of Protective Materials, Xingtai 054000, China
- Advanced Research Center of Thermal and New Energy Technologies, Hebei Vocational University of Technology and Engineering, Xingtai 054000, China
| | - Li-Jun Gao
- Hebei Key Laboratory of Man-machine Environmental Thermal Control Technology and Equipment, Filtration Performance and Environmental Health of Protective Materials, Xingtai 054000, China
- Advanced Research Center of Thermal and New Energy Technologies, Hebei Vocational University of Technology and Engineering, Xingtai 054000, China
| | - Tao Zhang
- School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Hui-Juan Xu
- Hebei Key Laboratory of Man-machine Environmental Thermal Control Technology and Equipment, Filtration Performance and Environmental Health of Protective Materials, Xingtai 054000, China
- Advanced Research Center of Thermal and New Energy Technologies, Hebei Vocational University of Technology and Engineering, Xingtai 054000, China
| | - Yan-Jun Bi
- Hebei Key Laboratory of Man-machine Environmental Thermal Control Technology and Equipment, Filtration Performance and Environmental Health of Protective Materials, Xingtai 054000, China
- Advanced Research Center of Thermal and New Energy Technologies, Hebei Vocational University of Technology and Engineering, Xingtai 054000, China
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21
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Cox J, Christensen B, Burton N, Dunn KH, Finnegan M, Ruess A, Estill C. Transmission of SARS-CoV-2 in the workplace: Key findings from a rapid review of the literature. AEROSOL SCIENCE AND TECHNOLOGY : THE JOURNAL OF THE AMERICAN ASSOCIATION FOR AEROSOL RESEARCH 2023; 57:233-254. [PMID: 37213938 PMCID: PMC10193509 DOI: 10.1080/02786826.2023.2166394] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 12/27/2022] [Indexed: 05/23/2023]
Abstract
At the beginning of the COVID-19 pandemic, the primary route of transmission of the SARS-CoV-2 virus was not well understood. Research gathered from other respiratory infectious diseases, including other coronaviruses, was the basis for the initial perceptions for transmission of SARS-CoV-2. To better understand transmission of SARS-CoV-2, a rapid literature review was conducted from literature generated March 19, 2020, through September 23, 2021. 18,616 unique results were identified from literature databases and screened. Of these, 279 key articles were reviewed and abstracted covering critical topics such as environmental/workplace monitoring, sampling and analytical method evaluation, and the ability of the virus to remain intact and infectious during sampling. This paper describes the results of the rapid literature review, which evaluated pathways that contribute to transmission as well as the strengths and limitations of current sampling approaches. This review also evaluates how different factors, including environmental conditions and surface characteristics, could impact the transmission potential of SARS-CoV-2. A continual rapid review in the midst of a pandemic proved particularly useful for quickly understanding the transmission parameters of the virus and enabled us to comprehensively assess literature, respond to workplace questions, and evaluate our understanding as the science evolved. Air and surface sampling with the accompanying analytical methods were not generally effective in recovering SARS-CoV-2 viable virus or RNA in many likely contaminated environments. In light of these findings, the development of validated sampling and analysis methods is critical for determining worker exposure to SARS-CoV-2 and to assess the impact of mitigation efforts.
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Affiliation(s)
- Jennie Cox
- National Institute for Occupational Safety and Health, Cincinnati, OH, USA
| | - Brian Christensen
- National Institute for Occupational Safety and Health, Cincinnati, OH, USA
| | - Nancy Burton
- National Institute for Occupational Safety and Health, Cincinnati, OH, USA
| | - Kevin H. Dunn
- National Institute for Occupational Safety and Health, Cincinnati, OH, USA
| | | | - Ana Ruess
- Gryphon Scientific, Takoma Park, MD, USA
| | - Cherie Estill
- National Institute for Occupational Safety and Health, Cincinnati, OH, USA
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22
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Hughes DM, Cheyne CP, Ashton M, Coffey E, Crozier A, Semple MG, Buchan I, García-Fiñana M. Association of SARS-CoV-2 viral load distributions with individual demographics and suspected variant type: results from the Liverpool community testing pilot, England, 6 November 2020 to 8 September 2021. Euro Surveill 2023; 28:2200129. [PMID: 36700865 PMCID: PMC9881177 DOI: 10.2807/1560-7917.es.2023.28.4.2200129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
BackgroundThe PCR quantification cycle (Cq) is a proxy measure of the viral load of a SARS-CoV-2-infected individual.AimTo investigate if Cq values vary according to different population characteristics, in particular demographic ones, and within the COVID-19 pandemic context, notably the SARS-CoV-2 type/variant individuals get infected with.MethodsWe considered all positive PCR results from Cheshire and Merseyside, England, between 6 November 2020 and 8 September 2021. Cq distributions were inspected with Kernel density estimates. Multivariable quantile regression models assessed associations between people's features and Cq.ResultsWe report Cq values for 188,821 SARS-CoV-2 positive individuals. Median Cqs increased with decreasing age for suspected wild-type virus and Alpha variant infections, but less so, if not, for Delta. For example, compared to 30-39-year-olds (median age group), 5-11-year-olds exhibited 1.8 (95% CI: 1.5 to 2.1), 2.2 (95% CI: 1.8 to 2.6) and 0.8 (95% CI: 0.6 to 0.9) higher median Cqs for suspected wild-type, Alpha and Delta positives, respectively, in multivariable analysis. 12-18-year-olds also had higher Cqs for wild-type and Alpha positives, however, not for Delta. Overall, in univariable analysis, suspected Delta positives reported 2.8 lower median Cqs than wild-type positives (95% CI: 2.7 to 2.8; p < 0.001). Suspected Alpha positives had 1.5 (95% CI: 1.4 to 1.5; p < 0.001) lower median Cqs than wild type.ConclusionsWild-type- or Alpha-infected school-aged children (5-11-year-olds) might transmit less than adults (> 18 years old), but have greater mixing exposures. Smaller differences in viral loads with age occurred in suspected Delta infections. Suspected-Alpha- or Delta-infections involved higher viral loads than wild type, suggesting increased transmission risk. COVID-19 control strategies should consider age and dominant variant.
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Affiliation(s)
- David M Hughes
- Department of Health Data Science, Institute of Population Health, University of Liverpool, Liverpool, United Kingdom
| | - Christopher P Cheyne
- Department of Health Data Science, Institute of Population Health, University of Liverpool, Liverpool, United Kingdom
| | - Matthew Ashton
- Department of Public Health, Liverpool City Council, Liverpool, United Kingdom
| | - Emer Coffey
- Department of Public Health, Liverpool City Council, Liverpool, United Kingdom
| | - Alex Crozier
- Division of biosciences, University College London, London, United Kingdom
| | - Malcolm G Semple
- Health Protection Research Unity in Emerging and Zoonotic Infections, Institute of Infection, Veterinary and Ecological Science, University of Liverpool, United Kingdom
| | - Iain Buchan
- Department of Public Health, Policy and Systems, Institute of Population Health, University of Liverpool, Liverpool, United Kingdom
| | - Marta García-Fiñana
- Department of Health Data Science, Institute of Population Health, University of Liverpool, Liverpool, United Kingdom
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23
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Baskak D, Ozbey S, Yucesan M, Gul M. COVID-19 safe campus evaluation for universities by a hybrid interval type-2 fuzzy decision-making model. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:8133-8153. [PMID: 36056282 PMCID: PMC9438885 DOI: 10.1007/s11356-022-22796-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 08/26/2022] [Indexed: 06/15/2023]
Abstract
The fight against the COVID-19 pandemic, which has affected the whole world in recent years and has had devastating effects on all segments of society, has been one of the most important priorities. The Turkish Standards Institution has determined a checklist to contribute to developing safe and clean environments in higher education institutions in Turkey and to follow-up on infection control measures. However, this study is only a checklist that makes it necessary for decision-makers to make a subjective evaluation during the evaluation process, while the need to develop a more effective, systematic framework that takes into account the importance levels of multiple criteria has emerged. Therefore, this study applies the best-worst method under interval type-2 fuzzy set concept (IT2F-BWM) to determine the importance levels of criteria affecting the "COVID-19 safe campus" evaluation of universities in the context of global pandemic. A three-level hierarchy consisting of three main criteria, 11 sub-criteria, and 58 sub-criteria has been created for this aim. Considering the hierarchy, the most important sub-criterion was determined as periodic disinfection. The high contribution of the interval-valued type-2 fuzzy sets in expressing the uncertainty in the decision-makers' evaluations and the fact that BWM provides criterion weights with a mathematical optimization model that produces less pairwise comparisons and higher consistency are the main factors in choosing this approach. Simple additive weighting (SAW) has also been injected into the IT2F-BWM to determine the safety level of any university campus regarding COVID-19. Thus, decision-makers will be better prepared for the devastating effects of the pandemic by first improving the factors that are relatively important in the fight against the pandemic. In addition, a threshold value will be determined by considering all criteria, and it will prepare the ground for a road map for campuses. A case study is employed to apply the proposed model, and a comparison study is also presented with the Bayesian BWM to validate the results of the criteria weights.
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Affiliation(s)
- Dilber Baskak
- Faculty of Health Sciences, Department of Emergency Aid and Disaster Management, Munzur University, Tunceli, Turkey
| | - Sumeyye Ozbey
- Faculty of Health Sciences, Department of Emergency Aid and Disaster Management, Munzur University, Tunceli, Turkey
| | - Melih Yucesan
- Faculty of Health Sciences, Department of Emergency Aid and Disaster Management, Munzur University, Tunceli, Turkey
| | - Muhammet Gul
- School of Transportation and Logistics, Istanbul University, 34320 Avcılar-Istanbul, Turkey
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24
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Anderson TL, Nande A, Merenstein C, Raynor B, Oommen A, Kelly BJ, Levy MZ, Hill AL. Quantifying individual-level heterogeneity in infectiousness and susceptibility through household studies. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2022:2022.12.02.22281853. [PMID: 36523404 PMCID: PMC9753792 DOI: 10.1101/2022.12.02.22281853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The spread of SARS-CoV-2, like that of many other pathogens, is governed by heterogeneity. "Superspreading," or "over-dispersion," is an important factor in transmission, yet it is hard to quantify. Estimates from contact tracing data are prone to potential biases due to the increased likelihood of detecting large clusters of cases, and may reflect variation in contact behavior more than biological heterogeneity. In contrast, the average number of secondary infections per contact is routinely estimated from household surveys, and these studies can minimize biases by testing all members of a household. However, the models used to analyze household transmission data typically assume that infectiousness and susceptibility are the same for all individuals or vary only with predetermined traits such as age. Here we develop and apply a combined forward simulation and inference method to quantify the degree of inter-individual variation in both infectiousness and susceptibility from observations of the distribution of infections in household surveys. First, analyzing simulated data, we show our method can reliably ascertain the presence, type, and amount of these heterogeneities with data from a sufficiently large sample of households. We then analyze a collection of household studies of COVID-19 from diverse settings around the world, and find strong evidence for large heterogeneity in both the infectiousness and susceptibility of individuals. Our results also provide a framework to improve the design of studies to evaluate household interventions in the presence of realistic heterogeneity between individuals.
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Affiliation(s)
- Thayer L Anderson
- Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD 21218
| | - Anjalika Nande
- Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD 21218
| | - Carter Merenstein
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Brinkley Raynor
- Department of Biostatistics, Epidemiology, & Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Anisha Oommen
- Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD 21218
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218
| | - Brendan J Kelly
- Division of Infectious Diseases, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Michael Z Levy
- Department of Biostatistics, Epidemiology, & Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Alison L Hill
- Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD 21218
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218
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Transmission of SARS-CoV-2 by children to contacts in schools and households: a prospective cohort and environmental sampling study in London. THE LANCET. MICROBE 2022; 3:e814-e823. [PMID: 36029775 PMCID: PMC9401977 DOI: 10.1016/s2666-5247(22)00124-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 04/20/2022] [Accepted: 04/29/2022] [Indexed: 01/14/2023]
Abstract
BACKGROUND Assessing transmission of SARS-CoV-2 by children in schools is of crucial importance to inform public health action. We assessed frequency of acquisition of SARS-CoV-2 by contacts of pupils with COVID-19 in schools and households, and quantified SARS-CoV-2 shedding into air and onto fomites in both settings. METHODS We did a prospective cohort and environmental sampling study in London, UK in eight schools. Schools reporting new cases of SARS-CoV-2 infection to local health protection teams were invited to take part if a child index case had been attending school in the 48 h before a positive SARS-CoV-2 PCR test. At the time of the study, PCR testing was available to symptomatic individuals only. Children aged 2-14 years (extended to <18 years in November, 2020) with a new nose or throat swab SARS-CoV-2 positive PCR from an accredited laboratory were included. Incidents involving exposure to at least one index pupil with COVID-19 were identified (the prevailing variants were original, α, and δ). Weekly PCR testing for SARS-CoV-2 was done on immediate classroom contacts (the so-called bubble), non-bubble school contacts, and household contacts of index pupils. Testing was supported by genome sequencing and on-surface and air samples from school and home environments. FINDINGS Between October, 2020, and July, 2021 from the eight schools included, secondary transmission of SARS-CoV-2 was not detected in 28 bubble contacts, representing ten bubble classes (participation rate 8·8% [IQR 4·6-15·3]). Across eight non-bubble classes, 3 (2%) of 62 pupils tested positive, but these were unrelated to the original index case (participation rate 22·5% [9·7-32·3]). All three were asymptomatic and tested positive in one setting on the same day. In contrast, secondary transmission to previously negative household contacts from infected index pupils was found in six (17%) of 35 household contacts rising to 13 (28%) of 47 household contacts when considering all potential infections in household contacts. Environmental contamination with SARS-CoV-2 was rare in schools: fomite SARS-CoV-2 was identified in four (2%) of 189 samples in bubble classrooms, two (2%) of 127 samples in non-bubble classrooms, and five (4%) of 130 samples in washrooms. This contrasted with fomites in households, where SARS-CoV-2 was identified in 60 (24%) of 248 bedroom samples, 66 (27%) of 241 communal room samples, and 21 (11%) 188 bathroom samples. Air sampling identified SARS-CoV-2 RNA in just one (2%) of 68 of school air samples, compared with 21 (25%) of 85 air samples taken in homes. INTERPRETATION There was no evidence of large-scale SARS-CoV-2 transmission in schools with precautions in place. Low levels of environmental contamination in schools are consistent with low transmission frequency and suggest adequate cleaning and ventilation in schools during the period of study. The high frequency of secondary transmission in households associated with evident viral shedding throughout the home suggests a need to improve advice to households with infection in children to prevent onward community spread. The data suggest that SARS-CoV-2 transmission from children in any setting is very likely to occur when precautions are reduced. FUNDING UK Research and Innovation and UK Department of Health and Social Care, National Institute for Health and Care Research.
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Mache C, Schulze J, Holland G, Bourquain D, Gensch JM, Oh DY, Nitsche A, Dürrwald R, Laue M, Wolff T. SARS-CoV-2 Omicron variant is attenuated for replication in a polarized human lung epithelial cell model. Commun Biol 2022; 5:1138. [PMID: 36302956 PMCID: PMC9610361 DOI: 10.1038/s42003-022-04068-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 10/04/2022] [Indexed: 11/09/2022] Open
Abstract
SARS-CoV-2 and its emerging variants of concern remain a major threat for global health. Here we introduce an infection model based upon polarized human Alveolar Epithelial Lentivirus immortalized (hAELVi) cells grown at the air-liquid interface to estimate replication and epidemic potential of respiratory viruses in the human lower respiratory tract. hAELVI cultures are highly permissive for different human coronaviruses and seasonal influenza A virus and upregulate various mediators following virus infection. Our analysis revealed a significantly reduced capacity of SARS-CoV-2 Omicron BA.1 and BA.2 variants to propagate in this human model compared to earlier D614G and Delta variants, which extends early risk assessments from epidemiological and animal studies suggesting a reduced pathogenicity of Omicron.
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Affiliation(s)
- Christin Mache
- Influenza and other Respiratory Viruses (Unit 17), Department of Infectious Diseases, Robert Koch Institute, Seestraße 10, 13353, Berlin, Germany
| | - Jessica Schulze
- Influenza and other Respiratory Viruses (Unit 17), Department of Infectious Diseases, Robert Koch Institute, Seestraße 10, 13353, Berlin, Germany
| | - Gudrun Holland
- Advanced Light and Electron Microscopy (ZBS 4), Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Seestraße 10, 13353, Berlin, Germany
| | - Daniel Bourquain
- Highly Pathogenic Viruses (ZBS 1), Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Seestraße 10, 13353, Berlin, Germany
| | - Jean-Marc Gensch
- Influenza and other Respiratory Viruses (Unit 17), Department of Infectious Diseases, Robert Koch Institute, Seestraße 10, 13353, Berlin, Germany
| | - Djin-Ye Oh
- Influenza and other Respiratory Viruses (Unit 17), Department of Infectious Diseases, Robert Koch Institute, Seestraße 10, 13353, Berlin, Germany
| | - Andreas Nitsche
- Highly Pathogenic Viruses (ZBS 1), Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Seestraße 10, 13353, Berlin, Germany
| | - Ralf Dürrwald
- Influenza and other Respiratory Viruses (Unit 17), Department of Infectious Diseases, Robert Koch Institute, Seestraße 10, 13353, Berlin, Germany
| | - Michael Laue
- Advanced Light and Electron Microscopy (ZBS 4), Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Seestraße 10, 13353, Berlin, Germany
| | - Thorsten Wolff
- Influenza and other Respiratory Viruses (Unit 17), Department of Infectious Diseases, Robert Koch Institute, Seestraße 10, 13353, Berlin, Germany.
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27
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Raymenants J, Duthoo W, Stakenborg T, Verbruggen B, Verplanken J, Feys J, Van Duppen J, Hanifa R, Marchal E, Lambrechts A, Maes P, André E, Van den Wijngaert N, Peumans P. Exhaled breath SARS-CoV-2 shedding patterns across variants of concern. Int J Infect Dis 2022; 123:25-33. [PMID: 35932968 PMCID: PMC9349369 DOI: 10.1016/j.ijid.2022.07.069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 07/27/2022] [Accepted: 07/27/2022] [Indexed: 12/14/2022] Open
Abstract
OBJECTIVES We performed exhaled breath (EB) and nasopharyngeal (NP) quantitative polymerase chain reaction (qPCR) and NP rapid antigen testing (NP RAT) of SARS-CoV-2 infections with different variants. METHODS We included immuno-naïve alpha-infected (n = 11) and partly boosted omicron-infected patients (n = 8) as high-risk contacts. We compared peak NP and EB qPCR cycle time (ct) values between cohorts (Wilcoxon-Mann-Whitney test). Test positivity was compared for three infection phases using Cochran Q test. RESULTS Peak median NP ct was 11.5 (interquartile range [IQR] 10.1-12.1) for alpha and 12.2 (IQR 11.1-15.3) for omicron infections. Peak median EB ct was 25.2 (IQR 24.5-26.9) and 28.3 (IQR 26.4-30.8) for alpha and omicron infections, respectively. Distributions did not differ between cohorts for NP (P = 0.19) or EB (P = 0.09). SARS-CoV-2 shedding peaked on day 1 in EB (confidence interval [CI] 0.0 - 4.5) and day 3 in NP (CI 1.5 - 6.0). EB qPCR positivity equaled NP qPCR positivity on D0-D1 (P = 0.44) and D2-D6 (P = 1.0). It superseded NP RAT positivity on D0-D1 (P = 0.003) and D2-D6 (P = 0.008). It was inferior to both on D7-D10 (P < 0.001). CONCLUSION Peak EB and nasopharynx shedding were comparable across variants. EB qPCR positivity matched NP qPCR and superseded NP RAT in the first week of infection.
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Affiliation(s)
- Joren Raymenants
- Laboratory of Clinical Microbiology, Department of Microbiology, Immunology and Transplantation, KU Leuven, 3000, Leuven, Belgium; Department of general internal medicine, University Hospitals Leuven, 3000, Leuven, Belgium.
| | - Wout Duthoo
- Imec Solutions department, imec, 3001, Leuven, Belgium
| | - Tim Stakenborg
- Life Science Technologies department, imec, 3001, Leuven, Belgium
| | | | - Julien Verplanken
- Enabling Digital Transformations department, imec, 9000, Ghent, Belgium
| | - Jos Feys
- Department of Clinical and Epidemiological Virology (Rega Institute), 3000, Leuven, Belgium
| | - Joost Van Duppen
- Life Science Technologies department, imec, 3001, Leuven, Belgium
| | - Rabea Hanifa
- Life Science Technologies department, imec, 3001, Leuven, Belgium
| | | | | | | | - Emmanuel André
- Laboratory of Clinical Microbiology, Department of Microbiology, Immunology and Transplantation, KU Leuven, 3000, Leuven, Belgium; Department of laboratory medicine, University Hospitals Leuven, 3000, Leuven, Belgium
| | | | - Peter Peumans
- Life Science Technologies department, imec, 3001, Leuven, Belgium
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Li X, Liang W, Yu C, Meng Q, Zhang W, Wu X, Xue J, Deng S, Wang H. Potential therapeutic strategies for quercetin targeting critical pathological mechanisms associated with colon adenocarcinoma and COVID-19. Front Pharmacol 2022; 13:988153. [PMID: 36249762 PMCID: PMC9557079 DOI: 10.3389/fphar.2022.988153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 08/30/2022] [Indexed: 11/13/2022] Open
Abstract
Patients with colon adenocarcinoma (COAD) are at a higher probability of infection with COVID-19 than healthy individuals. However, there is no globally accepted treatment protocol for patients with COAD/COVID-19. Quercetin has been found to have significant antitumor, antiviral and anti-inflammatory effects in several studies. Therefore, this study sought to evaluate the potential of quercetin as the agent for COAD/COVID-19 and to explore its mechanisms. We used bioinformatics algorithms to obtain COAD/COVID-19-related genes (CCRG) from COAD-related transcriptome data and COVID-related transcriptome sequencing data, and used these genes to construct a COAD prognostic model. We intersected the CCRG with the therapeutic target genes of quercetin and obtained a total of 105 genes (potential target genes of quercetin for the treatment of COAD/COVID-19). By constructing a protein-protein interaction (PPI) network, we ascertained FOS, NFKB1, NFKB1A, JUNB, and JUN as possible core target genes of quercetin for the treatment of COAD/COVID-19. Bioinformatic analysis of these 105 genes revealed that the mechanisms for quercetin the treatment of COAD/COVID-19 may be associated with oxidative stress, apoptosis, anti-inflammatory, immune, anti-viral and multiple pathways containing IL-17, TNF, HIF-1. In this study, we constructed a prognostic model of COAD/COVID19 patients by using CCRG and elucidated for the first time the potential target genes and molecular mechanisms of quercetin for the treatment of COAD/COVID-19, which may benefit the clinical treatment of COAD/COVID-19 patients. However, no clinical trials have yet been conducted to further validate the findings, but this will be the future direction of our research.
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Affiliation(s)
- Xiushen Li
- Department of Obstetrics and Gynecology, Shenzhen University General Hospital, Shenzhen, China
- Guangdong Key Laboratory for Biomedical Measurements and Ultrasound Imaging, School of Biomedical Engineering, Shenzhen University Health Science Center, Shenzhen, China
- Shenzhen Key Laboratory, Shenzhen University General Hospital, Shenzhen, China
| | - Weizheng Liang
- Central Laboratory, The First Affiliated Hospital of Hebei North University, Zhangjiakou, China
| | - Chengwei Yu
- School of Future Technology, University of Chinese Academy of Sciences, Beijing, China
| | - Qingxue Meng
- Central Laboratory, The First Affiliated Hospital of Hebei North University, Zhangjiakou, China
| | - Weiwen Zhang
- Department of Obstetrics and Gynecology, Shenzhen University General Hospital, Shenzhen, China
| | - Xueliang Wu
- Department of General Surgery, The First Affiliated Hospital of Hebei North University, Zhangjiakou, China
| | - Jun Xue
- Central Laboratory, The First Affiliated Hospital of Hebei North University, Zhangjiakou, China
- Department of General Surgery, The First Affiliated Hospital of Hebei North University, Zhangjiakou, China
- *Correspondence: Jun Xue, ; Shoulong Deng, ; Hao Wang,
| | - Shoulong Deng
- National Health Commission of China (NHC) Key Laboratory of Human Disease Comparative Medicine, Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences and Comparative Medicine Center, Peking Union Medical College, Beijing, China
- *Correspondence: Jun Xue, ; Shoulong Deng, ; Hao Wang,
| | - Hao Wang
- Department of Obstetrics and Gynecology, Shenzhen University General Hospital, Shenzhen, China
- Guangdong Key Laboratory for Biomedical Measurements and Ultrasound Imaging, School of Biomedical Engineering, Shenzhen University Health Science Center, Shenzhen, China
- Shenzhen Key Laboratory, Shenzhen University General Hospital, Shenzhen, China
- *Correspondence: Jun Xue, ; Shoulong Deng, ; Hao Wang,
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Hurraß J, Golmohammadi R, Bujok S, Bork M, Thelen F, Wagner P, Exner D, Schönfeld C, Hornei B, Kampf G, Exner M. Explosive COVID-19 outbreak in a German nursing home and the possible role of the air ventilation system. J Hosp Infect 2022; 130:34-43. [PMID: 36179793 PMCID: PMC9513403 DOI: 10.1016/j.jhin.2022.09.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 08/26/2022] [Accepted: 09/01/2022] [Indexed: 11/17/2022]
Abstract
Background Most COVID-19 outbreaks in nursing homes are explained by transmission of SARS-CoV-2 from nurses or visitors. Methods and results We describe an outbreak with 64 of the 67 residents identified as COVID-19 cases within two weeks (34 in nursing block 1, 30 in nursing block 2), at least 32 of them had relevant symptoms of COVID-19. Thirteen of the residents’ deaths were associated with COVID-19. In addition, 27 of approximately 60 staff members were identified as COVID-19 cases, 23 of them had relevant symptoms. In none of the samples from residents or staff was a mutation of SARS-CoV-2 detected. Quarantine of the residents was already in force at the beginning of the outbreak. A common source among the staff was considered to be unlikely because the two nursing home blocks had no staff rotation and the staff had to wear FFP2 masks during contact with residents. Three months after the outbreak the RNA of SARS-CoV-2 was detected on 14 of 39 sampled indoor surfaces of the air ventilation system with Ct values between 34.9 and 41.9, but only at the air supply in the corridor (11 of 24 samples) and the air overflow in the door between the corridor and the residents’ rooms (three of 11 samples) but not at the air exhaust in the residents’ bathrooms. Conclusions The air ventilation system and an inversion weather situation three days before the first confirmed case may have enhanced viral spread inside the nursing home assuming that a common source with a high viral load had existed at the time of outbreak.
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Affiliation(s)
- Julia Hurraß
- Public Health Department Cologne, Department of Infection Control and Environmental Hygiene, Neumarkt 15-21, 50667 Köln, Germany.
| | - Roshanak Golmohammadi
- Public Health Department Cologne, Department of Infection Control and Environmental Hygiene, Neumarkt 15-21, 50667 Köln, Germany
| | - Steffen Bujok
- Public Health Department Cologne, Department of Infection Control and Environmental Hygiene, Neumarkt 15-21, 50667 Köln, Germany
| | - Manfred Bork
- Public Health Department Cologne, Department of Infection Control and Environmental Hygiene, Neumarkt 15-21, 50667 Köln, Germany
| | - Finn Thelen
- Public Health Department Cologne, Department of Infection Control and Environmental Hygiene, Neumarkt 15-21, 50667 Köln, Germany
| | - Pia Wagner
- Public Health Department Cologne, Department of Infection Control and Environmental Hygiene, Neumarkt 15-21, 50667 Köln, Germany
| | - Daniel Exner
- General, Visceral-, Thoracic and Vascular Surgery, University Hospital Bonn, Venusberg Campus 1, 53127 Bonn, Germany
| | - Christine Schönfeld
- EKO, Institute for Laboratory Medicine and Clinical Microbiology, Virchowstr. 20, 46047 Oberhausen, Germany
| | - Britt Hornei
- EKO, Institute for Laboratory Medicine and Clinical Microbiology, Virchowstr. 20, 46047 Oberhausen, Germany
| | - Günter Kampf
- University Medicine Greifswald, Ferdinand-Sauerbruch-Strasse, 17475 Greifswald, Germany
| | - Martin Exner
- Institute for Hygiene and Public Health, University Bonn, Venusberg Campus 1, 53127 Bonn, Germany
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Geng Y, Wang Y. Stability and transmissibility of SARS-CoV-2 in the environment. J Med Virol 2022; 95:e28103. [PMID: 36039831 PMCID: PMC9537778 DOI: 10.1002/jmv.28103] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 08/24/2022] [Accepted: 08/25/2022] [Indexed: 01/11/2023]
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus causing the ongoing global coronavirus disease 2019 (COVID-19) pandemic, is believed to be transmitted primarily through respiratory droplets and aerosols. However, reports are increasing regarding the contamination of environmental surfaces, shared objects, and cold-chain foods with SARS-CoV-2 RNA and the possibility of environmental fomite transmission of the virus raises much concern and debate. This study summarizes the current knowledge regarding potential mechanisms of environmental transmission of SARS-CoV-2, including the prevalence of surface contamination in various settings, the viability and stability of the virus on surfaces or fomites, as well as environmental factors affecting virus viability and survival such as temperature and relative humidity. Instances of fomite transmission, including cold-chain food transmission, and the importance of fomite transmission in epidemics, are discussed. The knowledge gaps regarding fomite transmission of SARS-CoV-2 are also briefly analyzed.
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Affiliation(s)
- Yansheng Geng
- Key Laboratory of Public Health Safety of Hebei Province, School of Public HealthHebei UniversityBaodingChina
| | - Youchun Wang
- Division of HIV/AIDS and Sex‐Transmitted Virus VaccinesNational Institutes for Food and Drug ControlBeijingChina
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Kuylen EJ, Torneri A, Willem L, Libin PJK, Abrams S, Coletti P, Franco N, Verelst F, Beutels P, Liesenborgs J, Hens N. Different forms of superspreading lead to different outcomes: Heterogeneity in infectiousness and contact behavior relevant for the case of SARS-CoV-2. PLoS Comput Biol 2022; 18:e1009980. [PMID: 35994497 PMCID: PMC9436127 DOI: 10.1371/journal.pcbi.1009980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 09/01/2022] [Accepted: 06/29/2022] [Indexed: 11/18/2022] Open
Abstract
Superspreading events play an important role in the spread of several pathogens, such as SARS-CoV-2. While the basic reproduction number of the original Wuhan SARS-CoV-2 is estimated to be about 3 for Belgium, there is substantial inter-individual variation in the number of secondary cases each infected individual causes—with most infectious individuals generating no or only a few secondary cases, while about 20% of infectious individuals is responsible for 80% of new infections. Multiple factors contribute to the occurrence of superspreading events: heterogeneity in infectiousness, individual variations in susceptibility, differences in contact behavior, and the environment in which transmission takes place. While superspreading has been included in several infectious disease transmission models, research into the effects of different forms of superspreading on the spread of pathogens remains limited. To disentangle the effects of infectiousness-related heterogeneity on the one hand and contact-related heterogeneity on the other, we implemented both forms of superspreading in an individual-based model describing the transmission and spread of SARS-CoV-2 in a synthetic Belgian population. We considered its impact on viral spread as well as on epidemic resurgence after a period of social distancing. We found that the effects of superspreading driven by heterogeneity in infectiousness are different from the effects of superspreading driven by heterogeneity in contact behavior. On the one hand, a higher level of infectiousness-related heterogeneity results in a lower risk of an outbreak persisting following the introduction of one infected individual into the population. Outbreaks that did persist led to fewer total cases and were slower, with a lower peak which occurred at a later point in time, and a lower herd immunity threshold. Finally, the risk of resurgence of an outbreak following a period of lockdown decreased. On the other hand, when contact-related heterogeneity was high, this also led to fewer cases in total during persistent outbreaks, but caused outbreaks to be more explosive in regard to other aspects (such as higher peaks which occurred earlier, and a higher herd immunity threshold). Finally, the risk of resurgence of an outbreak following a period of lockdown increased. We found that these effects were conserved when testing combinations of infectiousness-related and contact-related heterogeneity. To investigate the effect of different sources of superspreading on disease dynamics, we implemented superspreading driven by heterogeneity in infectiousness and heterogeneity in contact behavior into an individual-based model for the transmission of SARS-CoV-2 in the Belgian population. We compared the impact of both forms of superspreading in a scenario without interventions as well as in a scenario in which a period of strict social distancing (i.e. a lockdown) is followed by a period of partial release. We found that both forms of superspreading have very different effects. On the one hand, increasing the level of infectiousness-related heterogeneity led to less outbreaks being observed following the introduction of one infected individual in the population. Furthermore, final outbreak sizes decreased, and outbreaks became slower, with lower and later peaks, and a lower herd immunity threshold. Finally, the risk for resurgence of an outbreak following a period of lockdown also decreased. On the other hand, when contact-related heterogeneity was high, this also led to smaller final sizes, but caused outbreaks to be more explosive regarding other aspects (such as higher peaks that occurred earlier). The herd immunity threshold also increased, as did the risk of resurgence of outbreaks.
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Affiliation(s)
- Elise J. Kuylen
- Centre for Health Economic Research and Modeling Infectious Diseases, University of Antwerp, Antwerp, Belgium
- Data Science Institute, I-BioStat, Hasselt University, Hasselt, Belgium
- * E-mail:
| | - Andrea Torneri
- Centre for Health Economic Research and Modeling Infectious Diseases, University of Antwerp, Antwerp, Belgium
| | - Lander Willem
- Centre for Health Economic Research and Modeling Infectious Diseases, University of Antwerp, Antwerp, Belgium
| | - Pieter J. K. Libin
- Data Science Institute, I-BioStat, Hasselt University, Hasselt, Belgium
- Artificial Intelligence Lab, Vrije Universiteit Brussel, Brussels, Belgium
- Rega Institute for Medical Research, Clinical and Epidemiological Virology, University of Leuven, Leuven, Belgium
| | - Steven Abrams
- Data Science Institute, I-BioStat, Hasselt University, Hasselt, Belgium
- Global Health Institute, University of Antwerp, Antwerp, Belgium
| | - Pietro Coletti
- Data Science Institute, I-BioStat, Hasselt University, Hasselt, Belgium
| | - Nicolas Franco
- Data Science Institute, I-BioStat, Hasselt University, Hasselt, Belgium
- Namur Institute for Complex Systems, Department of Mathematics, University of Namur, Namur, Belgium
| | - Frederik Verelst
- Centre for Health Economic Research and Modeling Infectious Diseases, University of Antwerp, Antwerp, Belgium
| | - Philippe Beutels
- Centre for Health Economic Research and Modeling Infectious Diseases, University of Antwerp, Antwerp, Belgium
- School of Public Health and Community Medicine, The University of New South Wales, Sydney, NSW, Australia
| | - Jori Liesenborgs
- Expertise Centre for Digital Media, Hasselt University - transnational University Limburg, Hasselt, Belgium
| | - Niel Hens
- Centre for Health Economic Research and Modeling Infectious Diseases, University of Antwerp, Antwerp, Belgium
- Data Science Institute, I-BioStat, Hasselt University, Hasselt, Belgium
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Empirical evidence on the efficiency of backward contact tracing in COVID-19. Nat Commun 2022; 13:4750. [PMID: 35963872 PMCID: PMC9375086 DOI: 10.1038/s41467-022-32531-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 08/03/2022] [Indexed: 11/09/2022] Open
Abstract
Standard contact tracing practice for COVID-19 is to identify persons exposed to an infected person during the contagious period, assumed to start two days before symptom onset or diagnosis. In the first large cohort study on backward contact tracing for COVID-19, we extended the contact tracing window by 5 days, aiming to identify the source of the infection and persons infected by the same source. The risk of infection amongst these additional contacts was similar to contacts exposed during the standard tracing window and significantly higher than symptomatic individuals in a control group, leading to 42% more cases identified as direct contacts of an index case. Compared to standard practice, backward traced contacts required fewer tests and shorter quarantine. However, they were identified later in their infectious cycle if infected. Our results support implementing backward contact tracing when rigorous suppression of viral transmission is warranted.
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SARS-CoV-2 viral load is associated with risk of transmission to household and community contacts. BMC Infect Dis 2022; 22:672. [PMID: 35931971 PMCID: PMC9354300 DOI: 10.1186/s12879-022-07663-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 07/29/2022] [Indexed: 12/23/2022] Open
Abstract
Background Factors that lead to successful SARS-CoV-2 transmission are still not well described. We investigated the association between a case’s viral load and the risk of transmission to contacts in the context of other exposure-related factors. Methods Data were generated through routine testing and contact tracing at a large university. Case viral loads were obtained from cycle threshold values associated with a positive polymerase chain reaction test result from October 1, 2020 to April 15, 2021. Cases were included if they had at least one contact who tested 3–14 days after the exposure. Case-contact pairs were formed by linking index cases with contacts. Chi-square tests were used to evaluate differences in proportions of contacts testing positive. Generalized estimating equation models with a log link were used to evaluate whether viral load and other exposure-related factors were associated with a contact testing positive. Results Median viral load among the 212 cases included in the study was 5.6 (1.8–10.4) log10 RNA copies per mL of saliva. Among 365 contacts, 70 (19%) tested positive following their exposure; 36 (51%) were exposed to a case that was asymptomatic or pre-symptomatic on the day of exposure. The proportion of contacts that tested positive increased monotonically with index case viral load (12%, 23% and 25% corresponding to < 5, 5–8 and > 8 log10 copies per mL, respectively; X2 = 7.18, df = 2, p = 0.03). Adjusting for cough, time between test and exposure, and physical contact, the risk of transmission to a close contact was significantly associated with viral load (RR = 1.27, 95% CI 1.22–1.32). Conclusions Further research is needed to understand whether these relationships persist for newer variants. For those variants whose transmission advantage is mediated through a high viral load, public health measures could be scaled accordingly. Index cases with higher viral loads could be prioritized for contact tracing and recommendations to quarantine contacts could be made according to the likelihood of transmission based on risk factors such as viral load.
Supplementary Information The online version contains supplementary material available at 10.1186/s12879-022-07663-1.
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34
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Hall R, Pal D, Ariya PA. Novel Dynamic Technique, Nano-DIHM, for Rapid Detection of Oil, Heavy Metals, and Biological Spills in Aquatic Systems. Anal Chem 2022; 94:11390-11400. [PMID: 35929664 DOI: 10.1021/acs.analchem.2c02396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Numerous anthropogenic and natural particle contaminants exist in diverse aquatic systems, with widely unknown environmental fates. We coupled a flow tube with a digital in-line holographic microscopy (nano-DIHM) technique for aquatic matrices, for in situ real-time analysis of particle size, shape, and phase. Nano-DIHM enables 4D tracking of particles in water and their transformations in three-dimensional space. We demonstrate that nano-DIHM can be automated to detect and track oil spills/oil droplets in dynamic systems. We provide evidence that nano-DIHM can detect the MS2 bacteriophage as a representative biological-viral material and mercury-containing particles alongside other heavy metals as common toxic contaminants. Nano-DIHM shows the capability of observation of combined materials in water, characterizing the interactions of various particles in mixtures, and particles with different coatings in a suspension. The observed sizes of the particles and droplets ranged from ∼1 to 200 μm. We herein demonstrate the ability of nano-DIHM to characterize and distinguish particle-based contaminants in water and their interactions in both stationary and dynamic modes with a 62.5 millisecond time resolution. The fully automated software for dynamic and real-time detection of contaminants will be of global significance. A comparison is also made between nano-DIHM and established techniques such as S/TEM for their different capabilities. Nano-DIHM can provide a range of physicochemical information in stationary and dynamic modes, allowing life cycle analysis of diverse particle contaminants in different aquatic systems, and serve as an effective tool for rapid response for spills and remediation of natural waters.
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Affiliation(s)
- Ryan Hall
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montréal, Quebec H3A 2K6, Canada
| | - Devendra Pal
- Department of Atmospheric and Oceanic Sciences, McGill University, 805 Sherbrooke Street West, Montreal, Quebec H3A 0B9, Canada
| | - Parisa A Ariya
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montréal, Quebec H3A 2K6, Canada.,Department of Atmospheric and Oceanic Sciences, McGill University, 805 Sherbrooke Street West, Montreal, Quebec H3A 0B9, Canada
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35
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Iddon C, Jones B, Sharpe P, Cevik M, Fitzgerald S. A population framework for predicting the proportion of people infected by the far-field airborne transmission of SARS-CoV-2 indoors. BUILDING AND ENVIRONMENT 2022; 221:109309. [PMID: 35757305 PMCID: PMC9212805 DOI: 10.1016/j.buildenv.2022.109309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 06/09/2022] [Accepted: 06/14/2022] [Indexed: 06/15/2023]
Abstract
The number of occupants in a space influences the risk of far-field airborne transmission of SARS-CoV-2 because the likelihood of having infectious and susceptible people both correlate with the number of occupants. This paper explores the relationship between occupancy and the probability of infection, and how this affects an individual person and a population of people. Mass-balance and dose-response models determine far-field transmission risks for an individual person and a population of people after sub-dividing a large reference space into 10 identical comparator spaces. For a single infected person, the dose received by an individual person in the comparator space is 10 times higher because the equivalent ventilation rate per infected person is lower when the per capita ventilation rate is preserved. However, accounting for population dispersion, such as the community prevalence of the virus, the probability of an infected person being present and uncertainty in their viral load, shows the transmission probability increases with occupancy and the reference space has a higher transmission risk. Also, far-field transmission is likely to be a rare event that requires a high emission rate, and there are a set of Goldilocks conditions that are just right when equivalent ventilation is effective at mitigating against transmission. These conditions depend on the viral load, because when they are very high or low, equivalent ventilation has little effect on transmission risk. Nevertheless, resilient buildings should deliver the equivalent ventilation rate required by standards as minimum.
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Affiliation(s)
- Christopher Iddon
- Department of Architecture and Built Environment, University of Nottingham, Nottingham, UK
| | - Benjamin Jones
- Department of Architecture and Built Environment, University of Nottingham, Nottingham, UK
| | - Patrick Sharpe
- Department of Architecture and Built Environment, University of Nottingham, Nottingham, UK
| | - Muge Cevik
- Department of Infection and Global Health, School of Medicine, University of St Andrews, St Andrews, UK
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Jimenez JL, Marr LC, Randall K, Ewing ET, Tufekci Z, Greenhalgh T, Tellier R, Tang JW, Li Y, Morawska L, Mesiano‐Crookston J, Fisman D, Hegarty O, Dancer SJ, Bluyssen PM, Buonanno G, Loomans MGLC, Bahnfleth WP, Yao M, Sekhar C, Wargocki P, Melikov AK, Prather KA. What were the historical reasons for the resistance to recognizing airborne transmission during the COVID-19 pandemic? INDOOR AIR 2022; 32:e13070. [PMID: 36040283 PMCID: PMC9538841 DOI: 10.1111/ina.13070] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 05/25/2022] [Accepted: 05/30/2022] [Indexed: 05/05/2023]
Abstract
The question of whether SARS-CoV-2 is mainly transmitted by droplets or aerosols has been highly controversial. We sought to explain this controversy through a historical analysis of transmission research in other diseases. For most of human history, the dominant paradigm was that many diseases were carried by the air, often over long distances and in a phantasmagorical way. This miasmatic paradigm was challenged in the mid to late 19th century with the rise of germ theory, and as diseases such as cholera, puerperal fever, and malaria were found to actually transmit in other ways. Motivated by his views on the importance of contact/droplet infection, and the resistance he encountered from the remaining influence of miasma theory, prominent public health official Charles Chapin in 1910 helped initiate a successful paradigm shift, deeming airborne transmission most unlikely. This new paradigm became dominant. However, the lack of understanding of aerosols led to systematic errors in the interpretation of research evidence on transmission pathways. For the next five decades, airborne transmission was considered of negligible or minor importance for all major respiratory diseases, until a demonstration of airborne transmission of tuberculosis (which had been mistakenly thought to be transmitted by droplets) in 1962. The contact/droplet paradigm remained dominant, and only a few diseases were widely accepted as airborne before COVID-19: those that were clearly transmitted to people not in the same room. The acceleration of interdisciplinary research inspired by the COVID-19 pandemic has shown that airborne transmission is a major mode of transmission for this disease, and is likely to be significant for many respiratory infectious diseases.
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Affiliation(s)
- Jose L. Jimenez
- Department of Chemistry and Cooperative Institute for Research in Environmental SciencesUniversity of ColoradoBoulderColoradoUSA
| | - Linsey C. Marr
- Department of Civil and Environmental EngineeringVirginia TechBlacksburgVirginiaUSA
| | | | | | - Zeynep Tufekci
- School of JournalismColumbia UniversityNew YorkNew YorkUSA
| | - Trish Greenhalgh
- Department of Primary Care Health SciencesMedical Sciences DivisionUniversity of OxfordOxfordUK
| | | | - Julian W. Tang
- Department of Respiratory SciencesUniversity of LeicesterLeicesterUK
| | - Yuguo Li
- Department of Mechanical EngineeringUniversity of Hong KongHong KongChina
| | - Lidia Morawska
- International Laboratory for Air Quality and HeathQueensland University of TechnologyBrisbaneQueenslandAustralia
| | | | - David Fisman
- Dalla Lana School of Public HealthUniversity of TorontoTorontoOntarioCanada
| | - Orla Hegarty
- School of Architecture, Planning & Environmental PolicyUniversity College DublinDublinIreland
| | - Stephanie J. Dancer
- Department of MicrobiologyHairmyres Hospital, Glasgow, and Edinburgh Napier UniversityGlasgowUK
| | - Philomena M. Bluyssen
- Faculty of Architecture and the Built EnvironmentDelft University of TechnologyDelftThe Netherlands
| | - Giorgio Buonanno
- Department of Civil and Mechanical EngineeringUniversity of Cassino and Southern LazioCassinoItaly
| | - Marcel G. L. C. Loomans
- Department of the Built EnvironmentEindhoven University of Technology (TU/e)EindhovenThe Netherlands
| | - William P. Bahnfleth
- Department of Architectural EngineeringThe Pennsylvania State UniversityUniversity ParkPennsylvaniaUSA
| | - Maosheng Yao
- College of Environmental Sciences and EngineeringPeking UniversityBeijingChina
| | - Chandra Sekhar
- Department of the Built EnvironmentNational University of SingaporeSingaporeSingapore
| | - Pawel Wargocki
- Department of Civil EngineeringTechnical University of DenmarkLyngbyDenmark
| | - Arsen K. Melikov
- Department of Civil EngineeringTechnical University of DenmarkLyngbyDenmark
| | - Kimberly A. Prather
- Scripps Institution of OceanographyUniversity of California San DiegoLa JollaCaliforniaUSA
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Molecular detection of SARS-COV-2 in exhaled breath at the point-of-need. Biosens Bioelectron 2022; 217:114663. [PMID: 36150327 PMCID: PMC9424122 DOI: 10.1016/j.bios.2022.114663] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 08/17/2022] [Accepted: 08/24/2022] [Indexed: 12/19/2022]
Abstract
The SARS-CoV-2 pandemic has highlighted the need for improved technologies to help control the spread of contagious pathogens. While rapid point-of-need testing plays a key role in strategies to rapidly identify and isolate infectious patients, current test approaches have significant shortcomings related to assay limitations and sample type. Direct quantification of viral shedding in exhaled particles may offer a better rapid testing approach, since SARS-CoV-2 is believed to spread mainly by aerosols. It assesses contagiousness directly, the sample is easy and comfortable to obtain, sampling can be standardized, and the limited sample volume lends itself to a fast and sensitive analysis. In view of these benefits, we developed and tested an approach where exhaled particles are efficiently sampled using inertial impaction in a micromachined silicon chip, followed by an RT-qPCR molecular assay to detect SARS-CoV-2 shedding. Our portable, silicon impactor allowed for the efficient capture (>85%) of respiratory particles down to 300 nm without the need for additional equipment. We demonstrate using both conventional off-chip and in-situ PCR directly on the silicon chip that sampling subjects’ breath in less than a minute yields sufficient viral RNA to detect infections as early as standard sampling methods. A longitudinal study revealed clear differences in the temporal dynamics of viral load for nasopharyngeal swab, saliva, breath, and antigen tests. Overall, after an infection, the breath-based test remains positive during the first week but is the first to consistently report a negative result, putatively signalling the end of contagiousness and further emphasizing the potential of this tool to help manage the spread of airborne respiratory infections.
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Nielsen BF, Eilersen A, Simonsen L, Sneppen K. Lockdowns exert selection pressure on overdispersion of SARS-CoV-2 variants. Epidemics 2022; 40:100613. [PMID: 35939969 PMCID: PMC9338171 DOI: 10.1016/j.epidem.2022.100613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 06/23/2022] [Accepted: 07/20/2022] [Indexed: 11/22/2022] Open
Abstract
The SARS-CoV-2 ancestral strain has caused pronounced superspreading events, reflecting a disease characterized by overdispersion, where about 10% of infected people cause 80% of infections. New variants of the disease have different person-to-person variability in viral load, suggesting for example that the Alpha (B.1.1.7) variant is more infectious but relatively less prone to superspreading. Meanwhile, non-pharmaceutical mitigation of the pandemic has focused on limiting social contacts (lockdowns, regulations on gatherings) and decreasing transmission risk through mask wearing and social distancing. Using a mathematical model, we show that the competitive advantage of disease variants may heavily depend on the restrictions imposed. In particular, we find that lockdowns exert an evolutionary pressure which favours variants with lower levels of overdispersion. Our results suggest that overdispersion is an evolutionarily unstable trait, with a tendency for more homogeneously spreading variants to eventually dominate. Novel variants of SARS-CoV-2 appear to be less prone to superspreading. A new model shows that it is advantageous for the pathogen to spread homogeneously. Interventions exert a selective pressure towards developing homogeneous transmission. The results have implications for the assessment of novel variants. Adds to understanding of how behaviour and interventions shape pathogen evolution.
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Hybrid measurement of respiratory aerosol reveals a dominant coarse fraction resulting from speech that remains airborne for minutes. Proc Natl Acad Sci U S A 2022; 119:e2203086119. [PMID: 35727979 PMCID: PMC9245670 DOI: 10.1073/pnas.2203086119] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Respiratory droplets are widely recognized as the primary vehicle in viral respiratory disease transmission. Accurate information on their number and size distributions is important for appropriate mitigation strategies, for quantitative modeling of airborne disease transmission, and for evaluating the relative importance of droplets originating from saliva versus airway lining fluid. A straightforward experimental setup using inexpensive, readily available components is developed for simultaneous characterization of larger particles by video analysis of laser light scattering and monitoring of smaller sizes by an optical particle counter. Measurements indicate that in a healthy volunteer, the airborne mass of speech aerosol far exceeds that generated by breathing, even when accounting for faster sedimentation of the larger particles. Accurate measurements of the size and quantity of aerosols generated by various human activities in different environments are required for efficacious mitigation strategies and accurate modeling of respiratory disease transmission. Previous studies of speech droplets, using standard aerosol instrumentation, reported very few particles larger than 5 μm. This starkly contrasts with the abundance of such particles seen in both historical slide deposition measurements and more recent light scattering observations. We have reconciled this discrepancy by developing an alternative experimental approach that addresses complications arising from nucleated condensation. Measurements reveal that a large volume fraction of speech-generated aerosol has diameters in the 5- to 20-μm range, making them sufficiently small to remain airborne for minutes, not hours. This coarse aerosol is too large to penetrate the lower respiratory tract directly, and its relevance to disease transmission is consistent with the vast majority of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections initiating in the upper respiratory tract. Our measurements suggest that in the absence of symptoms such as coughing or sneezing, the importance of speech-generated aerosol in the transmission of respiratory diseases is far greater than generally recognized.
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Prentiss M, Chu A, Berggren KK. Finding the infectious dose for COVID-19 by applying an airborne-transmission model to superspreader events. PLoS One 2022; 17:e0265816. [PMID: 35679278 PMCID: PMC9182663 DOI: 10.1371/journal.pone.0265816] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 03/08/2022] [Indexed: 12/19/2022] Open
Abstract
We probed the transmission of COVID-19 by applying an airborne transmission model to five well-documented case studies—a Washington state church choir, a Korean call center, a Korean exercise class, and two different Chinese bus trips. For all events the likely index patients were pre-symptomatic or mildly symptomatic, which is when infective patients are most likely to interact with large groups of people. Applying the model to those events yields results that suggest the following: (1) transmission was airborne; (2) superspreading events do not require an index patient with an unusually high viral load; (3) the viral loads for all of the index patients were of the same order of magnitude and consistent with experimentally measured values for patients at the onset of symptoms, even though viral loads across the population vary by a factor of >108. In particular we used a Wells-Riley exposure model to calculate q, the total average number of infectious quanta inhaled by a person at the event. Given the q value for each event, the simple airborne transmission model was used to determined Sq, the rate at which the index patient exhaled infectious quanta and N0, the characteristic number of COVID-19 virions needed to induce infection. Despite the uncertainties in the values of some parameters of the superspreading events, all five events yielded (N0∼300–2,000 virions), which is similar to published values for influenza. Finally, this work describes the conditions under which similar methods can provide actionable information on the transmission of other viruses.
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Affiliation(s)
- Mara Prentiss
- Department of Physics, Harvard University, Cambridge, MA, United States of America
- * E-mail:
| | - Arthur Chu
- QVT Family Office, New York, NY, United States of America
| | - Karl K. Berggren
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, United States of America
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Bauer K, Hardege R, Neumann S, Schwarze R, Fuchs M, Heinrich Pieper L. How Safe is Singing Under Pandemic Conditions? - CO 2-Measurements as Simple Method for Risk Estimation During Choir Rehearsals. J Voice 2022:S0892-1997(22)00136-9. [PMID: 35667988 DOI: 10.1016/j.jvoice.2022.05.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 05/02/2022] [Accepted: 05/02/2022] [Indexed: 11/16/2022]
Abstract
OBJECTIVES The SARS-CoV-2 pandemic has forced choirs to pause or at least to restrict rehearsals and concerts. Nevertheless, an uncertainty about the risks of infection while singing remains, especially with regard to distances, duration of singing, number of singers and their positions in the room, size of the room as well as ventilation strategies. Based on the assumption that CO2 is a suitable indicator for the exhaled aerosols in a room, it is the aim of this study to deduce recommendations for a choir rehearsal with a minimum risk of infection. METHODS During two choir rehearsals in a typical, nonventilated classroom, we installed 30 CO2 sensors, which allow spatial and temporal evaluation of the CO2 dispersion during singing. Various singing and ventilation phases were applied and the rates of CO2 increase during singing as well as its decrease during ventilation phases were evaluated and compared for different scenarios. RESULTS The measurements reveal a linear relation between the duration of singing, size of the room and number of persons. For our size of the room of 200 m3 the average CO2 increase is 1.83 ppm/min per person. Masks or pure breathing without singing do - in contrast to aerosol dispersion - not influence the rate of CO2 increase. CO2 disperses fast and homogeneously on horizontal planes. However, a vertical layering with a maximum CO2 concentration is observed near the ceiling. Shock ventilation shows the largest CO2 decrease within the first 5 min, after 10 min of ventilation the outside base concentration of 400 ppm is reached again. CONCLUSION The evaluated relations allow to calculate safe singing times for a defined number of singers and size of the room until a critical threshold of 800 ppm is reached. Furthermore, in order to monitor the actual CO2 concentration during choir rehearsal, just one CO2 sensor is representative for the air quality and CO2 concentration of the whole room and thus considered sufficient. For an early warning, it should be installed near the ceiling. Direct singing into a sensor should be avoided. A ventilation time of just 5 min is recommended which represents a compromise between strong CO2 reduction and still sufficient room temperature during winter time.
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Affiliation(s)
- Katrin Bauer
- Institute of Mechanics and Fluid Dynamics, TU Bergakademie Freiberg, Freiberg 09599, Germany.
| | - Robert Hardege
- Institute of Mechanics and Fluid Dynamics, TU Bergakademie Freiberg, Freiberg 09599, Germany
| | - Sebastian Neumann
- Institute of Mechanics and Fluid Dynamics, TU Bergakademie Freiberg, Freiberg 09599, Germany
| | - Rüdiger Schwarze
- Institute of Mechanics and Fluid Dynamics, TU Bergakademie Freiberg, Freiberg 09599, Germany
| | - Michael Fuchs
- Division of Phoniatrics and Audiology, University of Leipzig, Liebigstrasse 10-14, Leipzig 04103, Germany; Institute for Musicians' Medicine, University of Leipzig, Liebigstrasse 10-14, Leipzig 04103, Germany
| | - Lennart Heinrich Pieper
- Division of Phoniatrics and Audiology, University of Leipzig, Liebigstrasse 10-14, Leipzig 04103, Germany; Institute for Musicians' Medicine, University of Leipzig, Liebigstrasse 10-14, Leipzig 04103, Germany
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42
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Berrig C, Andreasen V, Frost Nielsen B. Heterogeneity in testing for infectious diseases. ROYAL SOCIETY OPEN SCIENCE 2022; 9:220129. [PMID: 35600424 PMCID: PMC9114977 DOI: 10.1098/rsos.220129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 04/28/2022] [Indexed: 05/03/2023]
Abstract
Testing strategies have varied widely between nation states during the COVID-19 pandemic, in intensity as well as methodology. Some countries have mainly performed diagnostic testing while others have opted for mass-screening for the presence of SARS-CoV-2 as well. COVID passport solutions have been introduced, in which access to several aspects of public life requires either testing, proof of vaccination or a combination thereof. This creates a coupling between personal activity levels and testing behaviour which, as we show in a mathematical model, leverages heterogeneous behaviours in a population and turns this heterogeneity from a disadvantage to an advantage for epidemic control.
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Affiliation(s)
- Christian Berrig
- Department of Science and Environment, Roskilde University, Universitetsvej 1, 4000 Roskilde, Denmark
| | - Viggo Andreasen
- Department of Science and Environment, Roskilde University, Universitetsvej 1, 4000 Roskilde, Denmark
| | - Bjarke Frost Nielsen
- Department of Science and Environment, Roskilde University, Universitetsvej 1, 4000 Roskilde, Denmark
- Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark
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43
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Schimmoller BJ, Trovão NS, Isbell M, Goel C, Heck BF, Archer TC, Cardinal KD, Naik NB, Dutta S, Daniel AR, Beheshti A. Covid-19 Exposure Assessment Tool (CEAT): Easy-to-use tool to quantify exposure based on airflow, group behavior, and infection prevalence in the community.. [PMID: 35291295 PMCID: PMC8923112 DOI: 10.1101/2022.03.02.22271806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The COVID-19 Exposure Assessment Tool (CEAT) allows users to compare respiratory relative risk to SARS-CoV-2 for various scenarios, providing understanding of how combinations of protective measures affect exposure, dose, and risk. CEAT incorporates mechanistic, stochastic and epidemiological factors including the: 1) emission rate of virus, 2) viral aerosol degradation and removal, 3) duration of activity/exposure, 4) inhalation rates, 5) ventilation rates (indoors/outdoors), 6) volume of indoor space, 7) filtration, 8) mask use and effectiveness, 9) distance between people, 10) group size, 11) current infection rates by variant, 12) prevalence of infection and immunity in the community, 13) vaccination rates of the community, and 14) implementation of COVID-19 testing procedures. Demonstration of CEAT, from published studies of COVID-19 transmission events, shows the model accurately predicts transmission. We also show how health and safety professionals at NASA Ames Research Center used CEAT to manage potential risks posed by SARS-CoV-2 exposures. Given its accuracy and flexibility, the wide use of CEAT will have a long lasting beneficial impact in managing both the current COVID-19 pandemic as well as a variety of other scenarios.
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44
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Mahmud MS, Kamrujjaman M, Adan MMIY, Hossain MA, Rahman MM, Islam MS, Mohebujjaman M, Molla MM. Vaccine efficacy and SARS-CoV-2 control in California and U.S. during the session 2020-2026: A modeling study. Infect Dis Model 2022; 7:62-81. [PMID: 34869959 PMCID: PMC8627016 DOI: 10.1016/j.idm.2021.11.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 11/01/2021] [Accepted: 11/09/2021] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Besides maintaining health precautions, vaccination has been the only prevention from SARS-CoV-2, though no clinically proved 100% effective vaccine has been developed till date. At this stage, to withhold the debris of this pandemic-experts need to know the impact of the vaccine efficacy rates, the threshold level of vaccine effectiveness and how long this pandemic may extent with vaccines that have different efficacy rates. In this article, a mathematical model study has been done on the importance of vaccination and vaccine efficiency rate during an ongoing pandemic. METHODS We simulated a five compartment mathematical model to analyze the pandemic scenario in both California, and whole U.S. We considered four vaccines, Pfizer (95%), Moderna (94%), AstraZeneca (79%), and Johnson & Johnson (72%), which are being used rigorously to control the SARS-CoV-2 pandemic, in addition with two special cases: a vaccine with 100% efficacy rate and no vaccine under use. SARS-CoV-2 related data of California, and U.S. were used in this study. FINDINGS Both the infection and death rates are very high in California. Our model suggests that the pandemic situation in California will be under control in the last quartile of the year 2023 if vaccination program is continued with the Pfizer vaccine. During this time, six waves may happen from the beginning of the immunization where the case fatality and recovery rates will be 1.697% and 98.30%, respectively. However, according to the considered model, this period might be extended to the mid of 2024 when vaccines with lower efficacy rates are used. On the other hand, the daily cases and deaths in the U.S. will be under control at the end of 2026 with multiple waves. Although the number of susceptible people will fall down to none in the beginning of 2027, there is less chance to stop the vaccination program if vaccinated with a vaccine other than a 100% effective vaccine or Pfizer, and at that case vaccination program must run till the mid of 2028. According to this study, the unconfirmed-infectious and infected cases will be under control at the end of 2027 and at the mid of 2028, respectively. INTERPRETATION The more effective a vaccine is, the less people suffer from this malign infection. Vaccines which are less than 90% effective do not have notable contribution to control the pandemic besides hard immunity. Furthermore, specific groups of people are getting prioritized initially, mass vaccination and quick responses are required to control the spread of this disease.
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Affiliation(s)
- Md Shahriar Mahmud
- Department of Computer Science and Engineering, State University of Bangladesh, Dhaka, 1205, Bangladesh
| | - Md Kamrujjaman
- Department of Mathematics, University of Dhaka, Dhaka, 1000, Bangladesh
- Department of Mathematics and Statistics, University of Calgary, Calgary, AB, Canada
| | | | - Md Alamgir Hossain
- Computational Biology Research Lab (CBRL), Department of Pharmacy, Jagannath University, Dhaka, 1100, Bangladesh
| | - Md Mizanur Rahman
- Hitotsubashi Institute for Advanced Study, Hitotsubashi University, Naka Kunitachi, Tokyo, 186-8601, Japan
| | - Md Shahidul Islam
- Department of Mathematics, University of Dhaka, Dhaka, 1000, Bangladesh
| | - Muhammad Mohebujjaman
- Department of Mathematics and Physics, Texas A&M International University, Laredo, TX, 78 041, USA
| | - Md Mamun Molla
- Department of Mathematics & Physics, North South University, Dhaka, 1229, Bangladesh
- Center for Applied Scientific Computing (CASC), North South University, Dhaka, 1229, Bangladesh
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45
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Abstract
Aerosol transmission has been officially recognized by the world health authority resulting from its overwhelming experimental and epidemiological evidences. Despite substantial progress, few additional actions were taken to prevent aerosol transmission, and many key scientific questions still await urgent investigations. The grand challenge, the effective control of aerosol transmission of COVID-19, remains unsolved. A better understanding of the viral shedding into the air has been developed, but its temporal pattern is largely unknown. Sampling tools, as one of the critical elements for studying SARS-CoV-2 aerosol, are not readily available around the world. Many of them are less capable of preserving the viability of SARS-CoV-2, thus offering no clues about viral aerosol infectivity. As evidenced, the viability of SARS-CoV-2 is also directly impacted by temperature, humidity, sunlight, and air pollutants. For SARS-CoV-2 aerosol detection, liquid samplers, together with real-time polymerase chain reaction (RT-PCR), are currently used in certain enclosed or semi-enclosed environments. Sensitive and rapid COVID-19 screening technologies are in great need. Among others, the breath-borne-based method emerges with global attention due to its advantages in sample collection and early disease detection. To collectively confront these challenges, scientists from different fields around the world need to fight together for the welfare of mankind. This review summarized the current understanding of the aerosol transmission of SARS-CoV-2 and identified the key knowledge gaps with a to-do list. This review also serves as a call for efforts to develop technologies to better protect the people in a forthcoming reopening world.
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46
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Why Does the Severity of COVID-19 Differ With Age?: Understanding the Mechanisms Underlying the Age Gradient in Outcome Following SARS-CoV-2 Infection. Pediatr Infect Dis J 2022; 41:e36-e45. [PMID: 34966142 PMCID: PMC8740029 DOI: 10.1097/inf.0000000000003413] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Although there are many hypotheses for the age-related difference in the severity of COVID-19, differences in innate, adaptive and heterologous immunity, together with differences in endothelial and clotting function, are the most likely mechanisms underlying the marked age gradient. Children have a faster and stronger innate immune response to SARS-CoV-2, especially in the nasal mucosa, which rapidly controls the virus. In contrast, adults can have an overactive, dysregulated and less effective innate response that leads to uncontrolled pro-inflammatory cytokine production and tissue injury. More recent exposure to other viruses and routine vaccines in children might be associated with protective cross-reactive antibodies and T cells against SARS-CoV-2. There is less evidence to support other mechanisms that have been proposed to explain the age-related difference in outcome following SARS-CoV-2 infection, including pre-existing immunity from exposure to common circulating coronaviruses, differences in the distribution and expression of the entry receptors ACE2 and TMPRSS2, and difference in viral load.
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47
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Cheng Q, Spear RC. Exploring the Local Determinants of SARS-CoV-2 Transmission and Control via an Exposure-Based Model. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:1801-1810. [PMID: 35015513 DOI: 10.1021/acs.est.1c05633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
A simulation model was developed aimed at assisting local public health authorities in exploring strategies for the suppression of SARS-CoV-2 transmission. A mechanistic modeling framework is utilized based on the daily airborne exposure of individuals defined in terms of inhaled viruses. Comparison of model outputs and observed data confirms that the model can generate realistic patterns of secondary cases. In the example investigated, the highest risk of being newly infected was among young adults, males, and people living in large households. Among risky occupations are food preparation and serving, personal care and service, sales, and production-related occupations. Results also show a pattern consistent with superspreading with 70% of initial cases who do not transmit at all while 13.4% of primary cases contribute 80% of secondary cases. The impacts of school closure and masking on the synthetic population are very small, but for students, school closure resulted in more time at home and increased secondary cases among them by over 25%. Requiring masks at schools decreased the case count by 80%. We conclude that the simulator can be useful in exploring local intervention scenarios and provides output useful in assessing the confidence that might be placed on its predictions.
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Affiliation(s)
- Qu Cheng
- Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, California 94720, United States
| | - Robert C Spear
- Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, California 94720, United States
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48
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Coldrick S, Kelsey A, Ivings MJ, Foat TG, Parker ST, Noakes CJ, Bennett A, Rickard H, Moore G. Modeling and experimental study of dispersion and deposition of respiratory emissions with implications for disease transmission. INDOOR AIR 2022; 32:e13000. [PMID: 35225395 PMCID: PMC9111502 DOI: 10.1111/ina.13000] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 01/05/2022] [Accepted: 01/29/2022] [Indexed: 05/16/2023]
Abstract
The ability to model the dispersion of pathogens in exhaled breath is important for characterizing transmission of the SARS-CoV-2 virus and other respiratory pathogens. A Computational Fluid Dynamics (CFD) model of droplet and aerosol emission during exhalations has been developed and for the first time compared directly with experimental data for the dispersion of respiratory and oral bacteria from ten subjects coughing, speaking, and singing in a small unventilated room. The modeled exhalations consist of a warm, humid, gaseous carrier flow and droplets represented by a discrete Lagrangian particle phase which incorporates saliva composition. The simulations and experiments both showed greater deposition of bacteria within 1 m of the subject, and the potential for a substantial number of bacteria to remain airborne, with no clear difference in airborne concentration of small bioaerosols (<10 μm diameter) between 1 and 2 m. The agreement between the model and the experimental data for bacterial deposition directly in front of the subjects was encouraging given the uncertainties in model input parameters and the inherent variability within and between subjects. The ability to predict airborne microbial dispersion and deposition gives confidence in the ability to model the consequences of an exhalation and hence the airborne transmission of respiratory pathogens such as SARS-CoV-2.
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Affiliation(s)
| | | | | | | | | | - Catherine J. Noakes
- Leeds Institute for Fluid DynamicsSchool of Civil EngineeringUniversity of LeedsLeedsUK
| | | | | | - Ginny Moore
- National Infection Service, UKHSASalisburyUK
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49
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Peng Z, Rojas ALP, Kropff E, Bahnfleth W, Buonanno G, Dancer SJ, Kurnitski J, Li Y, Loomans MGLC, Marr LC, Morawska L, Nazaroff W, Noakes C, Querol X, Sekhar C, Tellier R, Greenhalgh T, Bourouiba L, Boerstra A, Tang JW, Miller SL, Jimenez JL. Practical Indicators for Risk of Airborne Transmission in Shared Indoor Environments and Their Application to COVID-19 Outbreaks. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022. [PMID: 34985868 DOI: 10.1101/2021.04.21.21255898] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Some infectious diseases, including COVID-19, can undergo airborne transmission. This may happen at close proximity, but as time indoors increases, infections can occur in shared room air despite distancing. We propose two indicators of infection risk for this situation, that is, relative risk parameter (Hr) and risk parameter (H). They combine the key factors that control airborne disease transmission indoors: virus-containing aerosol generation rate, breathing flow rate, masking and its quality, ventilation and aerosol-removal rates, number of occupants, and duration of exposure. COVID-19 outbreaks show a clear trend that is consistent with airborne infection and enable recommendations to minimize transmission risk. Transmission in typical prepandemic indoor spaces is highly sensitive to mitigation efforts. Previous outbreaks of measles, influenza, and tuberculosis were also assessed. Measles outbreaks occur at much lower risk parameter values than COVID-19, while tuberculosis outbreaks are observed at higher risk parameter values. Because both diseases are accepted as airborne, the fact that COVID-19 is less contagious than measles does not rule out airborne transmission. It is important that future outbreak reports include information on masking, ventilation and aerosol-removal rates, number of occupants, and duration of exposure, to investigate airborne transmission.
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Affiliation(s)
- Z Peng
- Dept. of Chemistry and CIRES, University of Colorado, Boulder, Colorado 80309, United States
| | - A L Pineda Rojas
- CIMA, UMI-IFAECI/CNRS, FCEyN, Universidad de Buenos Aires─UBA/CONICET, Buenos Aires C1428EGA, Argentina
| | - E Kropff
- Leloir Institute─IIBBA/CONICET, CBA, Buenos Aires C1405BWE, Argentina
| | - W Bahnfleth
- Dept. of Architectural Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - G Buonanno
- Dept. of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Cassino 03043, Italy
| | - S J Dancer
- Dept. of Microbiology, NHS Lanarkshire, Glasgow, Scotland G75 8RG, U.K
- School of Applied Sciences, Edinburgh Napier University, Edinburgh, Scotland EH11 4BN, U.K
| | - J Kurnitski
- REHVA Technology and Research Committee, Tallinn University of Technology, Tallinn 19086, Estonia
| | - Y Li
- Dept. of Mechanical Engineering, The University of Hong Kong, Hong Kong 999077, China
| | - M G L C Loomans
- Dept. of the Built Environment, Eindhoven University of Technology, Eindhoven 5612 AZ, The Netherlands
| | - L C Marr
- Dept. of Civil and Environmental Engineering, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - L Morawska
- International Laboratory for Air Quality and Health, Queensland University of Technology, Brisbane, Queensland 4001, Australia
| | - W Nazaroff
- Dept. of Civil and Environmental Engineering, University of California, Berkeley, California 94720, United States
| | - C Noakes
- School of Civil Engineering, University of Leeds, Leeds LS2 9JT, U.K
| | - X Querol
- Institute of Environmental Assessment and Water Research, IDAEA, Spanish Research Council, CSIC, Barcelona 08034, Spain
| | - C Sekhar
- Dept. of the Built Environment, National University of Singapore , 117566 Singapore
| | - R Tellier
- Dept. of Medicine, McGill University and McGill University Health Centre, Montreal, Québec H4A 3J1, Canada
| | - T Greenhalgh
- Nuffield Dept. of Primary Care Health Sciences, University of Oxford, Oxford OX2 6GG, U.K
| | - L Bourouiba
- The Fluid Dynamics of Disease Transmission Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - A Boerstra
- REHVA (Federation of European Heating, Ventilation and Air Conditioning Associations), BBA Binnenmilieu, The Hague 2501 CJ, The Netherlands
| | - J W Tang
- Dept. of Respiratory Sciences, University of Leicester, Leicester LE1 7RH, U.K
| | - S L Miller
- Dept. of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309, United States
| | - J L Jimenez
- Dept. of Chemistry and CIRES, University of Colorado, Boulder, Colorado 80309, United States
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50
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Peng Z, Rojas ALP, Kropff E, Bahnfleth W, Buonanno G, Dancer SJ, Kurnitski J, Li Y, Loomans MGLC, Marr LC, Morawska L, Nazaroff W, Noakes C, Querol X, Sekhar C, Tellier R, Greenhalgh T, Bourouiba L, Boerstra A, Tang JW, Miller SL, Jimenez JL. Practical Indicators for Risk of Airborne Transmission in Shared Indoor Environments and Their Application to COVID-19 Outbreaks. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:1125-1137. [PMID: 34985868 DOI: 10.1021/acs.est.1c06531] [Citation(s) in RCA: 60] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Some infectious diseases, including COVID-19, can undergo airborne transmission. This may happen at close proximity, but as time indoors increases, infections can occur in shared room air despite distancing. We propose two indicators of infection risk for this situation, that is, relative risk parameter (Hr) and risk parameter (H). They combine the key factors that control airborne disease transmission indoors: virus-containing aerosol generation rate, breathing flow rate, masking and its quality, ventilation and aerosol-removal rates, number of occupants, and duration of exposure. COVID-19 outbreaks show a clear trend that is consistent with airborne infection and enable recommendations to minimize transmission risk. Transmission in typical prepandemic indoor spaces is highly sensitive to mitigation efforts. Previous outbreaks of measles, influenza, and tuberculosis were also assessed. Measles outbreaks occur at much lower risk parameter values than COVID-19, while tuberculosis outbreaks are observed at higher risk parameter values. Because both diseases are accepted as airborne, the fact that COVID-19 is less contagious than measles does not rule out airborne transmission. It is important that future outbreak reports include information on masking, ventilation and aerosol-removal rates, number of occupants, and duration of exposure, to investigate airborne transmission.
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Affiliation(s)
- Z Peng
- Dept. of Chemistry and CIRES, University of Colorado, Boulder, Colorado 80309, United States
| | - A L Pineda Rojas
- CIMA, UMI-IFAECI/CNRS, FCEyN, Universidad de Buenos Aires─UBA/CONICET, Buenos Aires C1428EGA, Argentina
| | - E Kropff
- Leloir Institute─IIBBA/CONICET, CBA, Buenos Aires C1405BWE, Argentina
| | - W Bahnfleth
- Dept. of Architectural Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - G Buonanno
- Dept. of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Cassino 03043, Italy
| | - S J Dancer
- Dept. of Microbiology, NHS Lanarkshire, Glasgow, Scotland G75 8RG, U.K
- School of Applied Sciences, Edinburgh Napier University, Edinburgh, Scotland EH11 4BN, U.K
| | - J Kurnitski
- REHVA Technology and Research Committee, Tallinn University of Technology, Tallinn 19086, Estonia
| | - Y Li
- Dept. of Mechanical Engineering, The University of Hong Kong, Hong Kong 999077, China
| | - M G L C Loomans
- Dept. of the Built Environment, Eindhoven University of Technology, Eindhoven 5612 AZ, The Netherlands
| | - L C Marr
- Dept. of Civil and Environmental Engineering, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - L Morawska
- International Laboratory for Air Quality and Health, Queensland University of Technology, Brisbane, Queensland 4001, Australia
| | - W Nazaroff
- Dept. of Civil and Environmental Engineering, University of California, Berkeley, California 94720, United States
| | - C Noakes
- School of Civil Engineering, University of Leeds, Leeds LS2 9JT, U.K
| | - X Querol
- Institute of Environmental Assessment and Water Research, IDAEA, Spanish Research Council, CSIC, Barcelona 08034, Spain
| | - C Sekhar
- Dept. of the Built Environment, National University of Singapore , 117566 Singapore
| | - R Tellier
- Dept. of Medicine, McGill University and McGill University Health Centre, Montreal, Québec H4A 3J1, Canada
| | - T Greenhalgh
- Nuffield Dept. of Primary Care Health Sciences, University of Oxford, Oxford OX2 6GG, U.K
| | - L Bourouiba
- The Fluid Dynamics of Disease Transmission Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - A Boerstra
- REHVA (Federation of European Heating, Ventilation and Air Conditioning Associations), BBA Binnenmilieu, The Hague 2501 CJ, The Netherlands
| | - J W Tang
- Dept. of Respiratory Sciences, University of Leicester, Leicester LE1 7RH, U.K
| | - S L Miller
- Dept. of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309, United States
| | - J L Jimenez
- Dept. of Chemistry and CIRES, University of Colorado, Boulder, Colorado 80309, United States
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