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Fung T, Goh J, Chisholm RA. Long-term effects of non-pharmaceutical interventions on total disease burden in parsimonious epidemiological models. J Theor Biol 2024; 587:111817. [PMID: 38599566 DOI: 10.1016/j.jtbi.2024.111817] [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: 09/28/2023] [Revised: 03/28/2024] [Accepted: 04/03/2024] [Indexed: 04/12/2024]
Abstract
The recent global COVID-19 pandemic resulted in governments enacting non-pharmaceutical interventions (NPIs) targeted at reducing transmission of SARS-CoV-2. But the NPIs also affected the transmission of viruses causing non-target seasonal respiratory diseases, including influenza and respiratory syncytial virus (RSV). In many countries, the NPIs were found to reduce cases of such seasonal respiratory diseases, but there is also evidence that subsequent relaxation of NPIs led to outbreaks of these diseases that were larger than pre-pandemic ones, due to the accumulation of susceptible individuals prior to relaxation. Therefore, the net long-term effects of NPIs on the total disease burden of non-target diseases remain unclear. Knowledge of this is important for infectious disease management and maintenance of public health. In this study, we shed light on this issue for the simplified scenario of a set of NPIs that prevent or reduce transmission of a seasonal respiratory disease for about a year and are then removed, using mathematical analyses and numerical simulations of a suite of four epidemiological models with varying complexity and generality. The model parameters were estimated using empirical data pertaining to seasonal respiratory diseases and covered a wide range. Our results showed that NPIs reduced the total disease burden of a non-target seasonal respiratory disease in the long-term. Expressed as a percentage of population size, the reduction was greater for larger values of the basic reproduction number and the immunity loss rate, reflecting larger outbreaks and hence more infections averted by imposition of NPIs. Our study provides a foundation for exploring the effects of NPIs on total disease burden in more-complex scenarios.
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Affiliation(s)
- Tak Fung
- Department of Biological Sciences, Faculty of Science, National University of Singapore, 14 Science Drive 4, Singapore 117558, Singapore.
| | - Jonah Goh
- Department of Biological Sciences, Faculty of Science, National University of Singapore, 14 Science Drive 4, Singapore 117558, Singapore.
| | - Ryan A Chisholm
- Department of Biological Sciences, Faculty of Science, National University of Singapore, 14 Science Drive 4, Singapore 117558, Singapore.
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Giannini F, Hogan AB, Sarna M, Glass K, Moore HC. Modelling respiratory syncytial virus age-specific risk of hospitalisation in term and preterm infants. BMC Infect Dis 2024; 24:510. [PMID: 38773455 PMCID: PMC11110433 DOI: 10.1186/s12879-024-09400-2] [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: 12/12/2023] [Accepted: 05/13/2024] [Indexed: 05/23/2024] Open
Abstract
BACKGROUND Respiratory syncytial virus (RSV) is the most common cause of acute lower respiratory infections in children worldwide. The highest incidence of severe disease is in the first 6 months of life, with infants born preterm at greatest risk for severe RSV infections. The licensure of new RSV therapeutics (a long-acting monoclonal antibody and a maternal vaccine) in Europe, USA, UK and most recently in Australia, has driven the need for strategic decision making on the implementation of RSV immunisation programs. Data driven approaches, considering the local RSV epidemiology, are critical to advise on the optimal use of these therapeutics for effective RSV control. METHODS We developed a dynamic compartmental model of RSV transmission fitted to individually-linked population-based laboratory, perinatal and hospitalisation data for 2000-2012 from metropolitan Western Australia (WA), stratified by age and prior exposure. We account for the differential risk of RSV-hospitalisation in full-term and preterm infants (defined as < 37 weeks gestation). We formulated a function relating age, RSV exposure history, and preterm status to the risk of RSV-hospitalisation given infection. RESULTS The age-to-risk function shows that risk of hospitalisation, given RSV infection, declines quickly in the first 12 months of life for all infants and is 2.6 times higher in preterm compared with term infants. The hospitalisation risk, given infection, declines to < 10% of the risk at birth by age 7 months for term infants and by 9 months for preterm infants. CONCLUSIONS The dynamic model, using the age-to-risk function, characterises RSV epidemiology for metropolitan WA and can now be extended to predict the impact of prevention measures. The stratification of the model by preterm status will enable the comparative assessment of potential strategies in the extended model that target this RSV risk group relative to all-population approaches. Furthermore, the age-to-risk function developed in this work has wider relevance to the epidemiological characterisation of RSV.
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Affiliation(s)
- Fiona Giannini
- Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, University of Western Australia, 15 Hospital Ave, Nedlands, WA, 6009, Australia.
| | - Alexandra B Hogan
- School of Population Health, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - Mohinder Sarna
- Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, University of Western Australia, 15 Hospital Ave, Nedlands, WA, 6009, Australia
- School of Population Health, Curtin University, Perth, WA, 6002, Australia
| | - Kathryn Glass
- Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, University of Western Australia, 15 Hospital Ave, Nedlands, WA, 6009, Australia
- National Centre for Epidemiology and Population Health, The Australian National University, 62 Mills Rd, Acton ACT, 2601, Australia
| | - Hannah C Moore
- Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, University of Western Australia, 15 Hospital Ave, Nedlands, WA, 6009, Australia
- School of Population Health, Curtin University, Perth, WA, 6002, Australia
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Minney‐Smith CA, Foley DA, Sikazwe CT, Levy A, Smith DW. The seasonality of respiratory syncytial virus in Western Australia prior to implementation of SARS‐CoV‐2 non‐pharmaceutical interventions. Influenza Other Respir Viruses 2023; 17:e13117. [PMID: 36970572 PMCID: PMC10035409 DOI: 10.1111/irv.13117] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 01/27/2023] [Accepted: 02/14/2023] [Indexed: 03/11/2023] Open
Abstract
Background Respiratory syncytial virus (RSV) seasonality is dependent on the local climate. We assessed the stability of RSV seasonality prior to the SARS-CoV-2 pandemic in Western Australia (WA), a state spanning temperate and tropical regions. Method RSV laboratory testing data were collected from January 2012 to December 2019. WA was divided into three regions determined by population density and climate: Metropolitan, Northern and Southern. Season threshold was calculated per region at 1.2% annual cases, with onset the first of ≥2 weeks above this threshold and offset as the last week before ≥2 weeks below. Results The detection rate of RSV in WA was 6.3/10,000. The Northern region had the highest detection rate (15/10,000), more than 2.5 times the Metropolitan region (detection rate ratio 2.7; 95% CI, 2.6-2.9). Test percentage positive was similar in the Metropolitan (8.6%) and Southern (8.7%) regions, with the lowest in the Northern region (8.1%). RSV seasons in the Metropolitan and Southern regions occurred annually, with a single peak and had consistent timing and intensity. The Northern tropical region did not experience a distinct season. Proportion of RSV A to RSV B in the Northern region differed from the Metropolitan region in 5 of the 8 years studied. Conclusions Detection rate of RSV in WA is high, especially in the Northern region, where climate, an expanded at-risk population and increased testing may have contributed to greater numbers. Before the SARS-CoV-2 pandemic, RSV seasonality in WA was consistent in timing and intensity for the Metropolitan and Southern regions.
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Affiliation(s)
- Cara A. Minney‐Smith
- Department of Microbiology PathWest Laboratory Medicine WA Nedlands Western Australia Australia
| | - David A. Foley
- Department of Microbiology PathWest Laboratory Medicine WA Nedlands Western Australia Australia
- Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute University of Western Australia Perth Western Australia Australia
- School of Medicine University of Western Australia Perth Western Australia Australia
| | - Chisha T. Sikazwe
- Department of Microbiology PathWest Laboratory Medicine WA Nedlands Western Australia Australia
- Infection, and Immunity, Biomedical Sciences University of Western Australia Perth Western Australia Australia
| | - Avram Levy
- Department of Microbiology PathWest Laboratory Medicine WA Nedlands Western Australia Australia
- Infection, and Immunity, Biomedical Sciences University of Western Australia Perth Western Australia Australia
| | - David W. Smith
- Department of Microbiology PathWest Laboratory Medicine WA Nedlands Western Australia Australia
- School of Medicine University of Western Australia Perth Western Australia Australia
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Ratti C, Greca AD, Bertoncelli D, Rubini M, Tchana B. Prophylaxis protects infants with congenital heart disease from severe forms of RSV infection: an Italian observational retrospective study : Palivizumab prophylaxis in children with congenital heart disease. Ital J Pediatr 2023; 49:4. [PMID: 36631870 PMCID: PMC9835345 DOI: 10.1186/s13052-022-01399-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 12/19/2022] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND In children with congenital heart disease (CHD) respiratory syncytial virus (RSV) infection may have a severe course, with increased risk of morbidity and mortality, requiring hospital admission and intensive care. The aim of the present study was to evaluate the effect of prophylaxis with palivizumab in preventing RSV-associated hospitalization in infants with CHD. METHODS We carried out an observational, retrospective study in a paediatric cardiology division at a secondary-care centre in Italy, extracting from the database children with CHD who, from November 2004 to March 2022, matched the criteria for palivizumab prophylaxis, to evaluate the hospitalization rate in CHD patients with and without palivizumab prophylaxis and their RSV-related hospitalization characteristics compared with a group of children without CHD and no other underlying clinical conditions (control group, CG), hospitalized for RSV infection. RESULTS One hundred twenty-eight children with CHD were enrolled in the study, mainly (71.9%) with increased pulmonary flow, and received palivizumab prophylaxis. Twenty-seven received hospital care for bronchiolitis. Almost all CHD patients hospitalized for bronchiolitis (26 out of 27) received partial prophylaxis (≤ 3 doses). CHD patients with bronchiolitis stay longer in the hospital than control (14.4 ± 21.7 days vs 6.2 ± 2.3 days) some of which require intensive care (n = 4). CONCLUSIONS Our study provides evidence of the efficacy of palivizumab in protecting patients with hemodynamically significant CHD under the age of 2 years from RSV disease and its life-threatening complications. Reducing hospitalisation rate, morbidity, and mortality in this category of patients, passive immune prophylaxis with palivizumab may impact healthcare resource availability and utilisation.
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Affiliation(s)
- Chiara Ratti
- grid.411482.aPediatric Cardiology Unit, General and University Hospital of Parma, Parma, Italy
| | - Anna della Greca
- grid.411482.aPediatric Cardiology Unit, General and University Hospital of Parma, Parma, Italy
| | - Deborah Bertoncelli
- grid.411482.aPediatric Cardiology Unit, General and University Hospital of Parma, Parma, Italy
| | - Monica Rubini
- grid.411482.aGeneral and Emergency Pediatric Unit, General and University Hospital of Parma, Parma, Italy
| | - Bertrand Tchana
- grid.411482.aPediatric Cardiology Unit, General and University Hospital of Parma, Parma, Italy
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Determinants of RSV epidemiology following suppression through pandemic contact restrictions. Epidemics 2022; 40:100614. [PMID: 35901639 PMCID: PMC9301974 DOI: 10.1016/j.epidem.2022.100614] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 06/26/2022] [Accepted: 07/20/2022] [Indexed: 01/21/2023] Open
Abstract
INTRODUCTION COVID-19 related non-pharmaceutical interventions (NPIs) led to a suppression of RSV circulation in winter 2020/21 in the UK and an off-season resurgence in Summer 2021. We explore how the parameters of RSV epidemiology shape the size and dynamics of post-suppression resurgence and what we can learn about them from the resurgence patterns observed so far. METHODS We developed an age-structured dynamic transmission model of RSV and sampled the parameters governing RSV seasonality, infection susceptibility and post-infection immunity, retaining simulations fitting the UK's pre-pandemic epidemiology by a set of global criteria consistent with likelihood calculations. From Spring 2020 to Summer 2021 we assumed a reduced contact frequency, returning to pre-pandemic levels from Spring 2021. We simulated transmission forwards until 2023 and evaluated the impact of the sampled parameters on the projected trajectories of RSV hospitalisations and compared these to the observed resurgence. RESULTS Simulations replicated an out-of-season resurgence of RSV in 2021. If unmitigated, paediatric RSV hospitalisation incidence in the 2021/22 season was projected to increase by 30-60% compared to pre-pandemic levels. The increase was larger if infection risk was primarily determined by immunity acquired from previous exposure rather than age-dependent factors, exceeding 90 % and 130 % in 1-2 and 2-5 year old children, respectively. Analysing the simulations replicating the observed early outbreak in 2021 in addition to pre-pandemic RSV data, we found they were characterised by weaker seasonal forcing, stronger age-dependence of infection susceptibility and higher baseline transmissibility. CONCLUSION COVID-19 mitigation measures in the UK stopped RSV circulation in the 2020/21 season and generated immunity debt leading to an early off-season RSV epidemic in 2021. A stronger dependence of infection susceptibility on immunity from previous exposure increases the size of the resurgent season. The early onset of the RSV resurgence in 2021, its marginally increased size relative to previous seasons and its decline by January 2022 suggest a stronger dependence of infection susceptibility on age-related factors, as well as a weaker effect of seasonality and a higher baseline transmissibility. The pattern of resurgence has been complicated by contact levels still not back to pre-pandemic levels. Further fitting of RSV resurgence in multiple countries incorporating data on contact patterns will be needed to further narrow down these parameters and to better predict the pathogen's future trajectory, planning for a potential expansion of new immunisation products against RSV in the coming years.
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Mathematical Modeling: Global Stability Analysis of Super Spreading Transmission of Respiratory Syncytial Virus (RSV) Disease. COMPUTATION 2022. [DOI: 10.3390/computation10070120] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In this paper, a model for the transmission of respiratory syncytial virus (RSV) in a constant human population in which there exist super spreading infected individuals (who infect many people during a single encounter) is considered. It has been observed in the epidemiological data for the diseases caused by this virus that there are cases where some individuals are super-spreaders of the virus. We formulate a simply SEIrIsR (susceptible–exposed–regular infected–super-spreading infected–recovered) mathematical model to describe the dynamics of the transmission of this disease. The proposed model is analyzed using the standard stability method by using Routh-Hurwitz criteria. We obtain the basic reproductive number (R0) using the next generation method. We establish that when R0<1, the disease-free state is locally asymptotically stable and the disease endemic state is unstable. The reverse is true when R0>1, the disease endemic state becomes the locally asymptotically stable state and the disease-free state becomes unstable. It is also established that the two equilibrium states are globally asymptotically stable. The numerical simulations show how the dynamics of the disease change as values of the parameters in the SEIrIsR are varied.
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Waterlow NR, Toizumi M, van Leeuwen E, Thi Nguyen HA, Myint-Yoshida L, Eggo RM, Flasche S. Evidence for influenza and RSV interaction from 10 years of enhanced surveillance in Nha Trang, Vietnam, a modelling study. PLoS Comput Biol 2022; 18:e1010234. [PMID: 35749561 PMCID: PMC9262224 DOI: 10.1371/journal.pcbi.1010234] [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: 11/04/2021] [Revised: 07/07/2022] [Accepted: 05/20/2022] [Indexed: 11/19/2022] Open
Abstract
Influenza and Respiratory Syncytial Virus (RSV) interact within their host posing the concern for impacts on heterologous viruses following vaccination. We aimed to estimate the population level impact of their interaction. We developed a dynamic age-stratified two-pathogen mathematical model that includes pathogen interaction through competition for infection and enhanced severity of dual infections. We used parallel tempering to fit its parameters to 11 years of enhanced hospital-based surveillance for acute respiratory illnesses (ARI) in children under 5 years old in Nha Trang, Vietnam. The data supported either a 41% (95%CrI: 36–54) reduction in susceptibility following infection and for 10.0 days (95%CrI 7.1–12.8) thereafter, or no change in susceptibility following infection. We estimate that co-infection increased the probability for an infection in <2y old children to be reported 7.2 fold (95%CrI 5.0–11.4); or 16.6 fold (95%CrI 14.5–18.4) in the moderate or low interaction scenarios. Absence of either pathogen was not to the detriment of the other. We find stronger evidence for severity enhancing than for acquisition limiting interaction. In this setting vaccination against either pathogen is unlikely to have a major detrimental effect on the burden of disease caused by the other. Influenza and Respiratory Syncytial Virus (RSV) cause large burdens of disease. Instead of acting independently, there may be short term cross-protection between them. The evidence of this to date comes from ecological studies which are unable to test the mechanism, or biological studies that are unable to determine the population level impacts of such cross-protection. We create a mathematical model that simulates the circulation of these two viruses, and allows for cross-protection between them. We then fit this model to hospital reported cases of confirmed infection from Nha Trang, Vietnam in order to estimate whether any cross-protection exists in this setting. We show that there are two possibilities—either no interaction or moderate interaction that can result in the observed circulation patterns. However, we further show that co-infection results in an increased reporting rate, presumably due to increased severity.
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Affiliation(s)
- Naomi R. Waterlow
- Centre for Mathematical Modelling of Infectious Disease, London School of Hygiene and Tropical Medicine, London, United Kingdom
- * E-mail:
| | - Michiko Toizumi
- Department of Pediatric Infectious Diseases, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
| | - Edwin van Leeuwen
- Centre for Mathematical Modelling of Infectious Disease, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Statistics, Modelling and Economics Department, UKHSA, London, United Kingdom
| | | | - Lay Myint-Yoshida
- Department of Pediatric Infectious Diseases, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
| | - Rosalind M. Eggo
- Centre for Mathematical Modelling of Infectious Disease, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Stefan Flasche
- Centre for Mathematical Modelling of Infectious Disease, London School of Hygiene and Tropical Medicine, London, United Kingdom
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8
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Mathematical Modeling to Study Optimal Allocation of Vaccines against COVID-19 Using an Age-Structured Population. AXIOMS 2022. [DOI: 10.3390/axioms11030109] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Vaccination against the coronavirus disease 2019 (COVID-19) started in early December of 2020 in the USA. The efficacy of the vaccines vary depending on the SARS-CoV-2 variant. Some countries have been able to deploy strong vaccination programs, and large proportions of their populations have been fully vaccinated. In other countries, low proportions of their populations have been vaccinated, due to different factors. For instance, countries such as Afghanistan, Cameroon, Ghana, Haiti and Syria have less than 10% of their populations fully vaccinated at this time. Implementing an optimal vaccination program is a very complex process due to a variety of variables that affect the programs. Besides, science, policy and ethics are all involved in the determination of the main objectives of the vaccination program. We present two nonlinear mathematical models that allow us to gain insight into the optimal vaccination strategy under different situations, taking into account the case fatality rate and age-structure of the population. We study scenarios with different availabilities and efficacies of the vaccines. The results of this study show that for most scenarios, the optimal allocation of vaccines is to first give the doses to people in the 55+ age group. However, in some situations the optimal strategy is to first allocate vaccines to the 15–54 age group. This situation occurs whenever the SARS-CoV-2 transmission rate is relatively high and the people in the 55+ age group have a transmission rate 50% or less that of those in the 15–54 age group. This study and similar ones can provide scientific recommendations for countries where the proportion of vaccinated individuals is relatively small or for future pandemics.
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Use of mathematical modelling to assess respiratory syncytial virus epidemiology and interventions: a literature review. J Math Biol 2022; 84:26. [PMID: 35218424 PMCID: PMC8882104 DOI: 10.1007/s00285-021-01706-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 09/10/2021] [Accepted: 12/01/2021] [Indexed: 11/17/2022]
Abstract
Respiratory syncytial virus (RSV) is a leading cause of acute lower respiratory tract infection worldwide, resulting in approximately sixty thousand annual hospitalizations of< 5-year-olds in the United States alone and three million annual hospitalizations globally. The development of over 40 vaccines and immunoprophylactic interventions targeting RSV has the potential to significantly reduce the disease burden from RSV infection in the near future. In the context of RSV, a highly contagious pathogen, dynamic transmission models (DTMs) are valuable tools in the evaluation and comparison of the effectiveness of different interventions. This review, the first of its kind for RSV DTMs, provides a valuable foundation for future modelling efforts and highlights important gaps in our understanding of RSV epidemics. Specifically, we have searched the literature using Web of Science, Scopus, Embase, and PubMed to identify all published manuscripts reporting the development of DTMs focused on the population transmission of RSV. We reviewed the resulting studies and summarized the structure, parameterization, and results of the models developed therein. We anticipate that future RSV DTMs, combined with cost-effectiveness evaluations, will play a significant role in shaping decision making in the development and implementation of intervention programs.
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Abstract
The first round of vaccination against coronavirus disease 2019 (COVID-19) began in early December of 2020 in a few countries. There are several vaccines, and each has a different efficacy and mechanism of action. Several countries, for example, the United Kingdom and the USA, have been able to develop consistent vaccination programs where a great percentage of the population has been vaccinated (May 2021). However, in other countries, a low percentage of the population has been vaccinated due to constraints related to vaccine supply and distribution capacity. Countries such as the USA and the UK have implemented different vaccination strategies, and some scholars have been debating the optimal strategy for vaccine campaigns. This problem is complex due to the great number of variables that affect the relevant outcomes. In this article, we study the impact of different vaccination regimens on main health outcomes such as deaths, hospitalizations, and the number of infected. We develop a mathematical model of COVID-19 transmission to focus on this important health policy issue. Thus, we are able to identify the optimal strategy regarding vaccination campaigns. We find that for vaccines with high efficacy (>70%) after the first dose, the optimal strategy is to delay inoculation with the second dose. On the other hand, for a low first dose vaccine efficacy, it is better to use the standard vaccination regimen of 4 weeks between doses. Thus, under the delayed second dose option, a campaign focus on generating a certain immunity in as great a number of people as fast as possible is preferable to having an almost perfect immunity in fewer people first. Therefore, based on these results, we suggest that the UK implemented a better vaccination campaign than that in the USA with regard to time between doses. The results presented here provide scientific guidelines for other countries where vaccination campaigns are just starting, or the percentage of vaccinated people is small.
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Affiliation(s)
- Gilberto Gonzalez-Parra
- Department of Mathematics, New Mexico Tech, New Mexico Institute of Mining and Technology, Socorro, NM 87801, USA
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11
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A Multivariate Age-Structured Stochastic Model with Immunization Strategies to Describe Bronchiolitis Dynamics. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18147607. [PMID: 34300058 PMCID: PMC8305028 DOI: 10.3390/ijerph18147607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 07/12/2021] [Accepted: 07/14/2021] [Indexed: 11/24/2022]
Abstract
Bronchiolitis has a high morbidity in children under 2 years old. Respiratory syncytial virus (RSV) is the most common pathogen causing the disease. At present, there is only a costly humanized monoclonal RSV-specific antibody to prevent RSV. However, different immunization strategies are being developed. Hence, evaluation and comparison of their impact is important for policymakers. The analysis of the disease with a Bayesian stochastic compartmental model provided an improved and more natural description of its dynamics. However, the consideration of different age groups is still needed, since disease transmission greatly varies with age. In this work, we propose a multivariate age-structured stochastic model to understand bronchiolitis dynamics in children younger than 2 years of age considering high-quality data from the Valencia health system integrated database. Our modeling approach combines ideas from compartmental models and Bayesian hierarchical Poisson models in a novel way. Finally, we develop an extension of the model that simulates the effect of potential newborn immunization scenarios on the burden of disease. We provide an app tool that estimates the expected reduction in bronchiolitis episodes for a range of different values of uptake and effectiveness.
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12
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Waterlow NR, Flasche S, Minter A, Eggo RM. Competition between RSV and influenza: Limits of modelling inference from surveillance data. Epidemics 2021; 35:100460. [PMID: 33838587 PMCID: PMC8193815 DOI: 10.1016/j.epidem.2021.100460] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 03/24/2021] [Accepted: 03/24/2021] [Indexed: 10/28/2022] Open
Abstract
Respiratory Syncytial Virus (RSV) and Influenza cause a large burden of disease. Evidence of their interaction via temporary cross-protection implies that prevention of one could inadvertently lead to an increase in the burden of the other. However, evidence for the public health impact of such interaction is sparse and largely derives from ecological analyses of peak shifts in surveillance data. To test the robustness of estimates of interaction parameters between RSV and Influenza from surveillance data we conducted a simulation and back-inference study. We developed a two-pathogen interaction model, parameterised to simulate RSV and Influenza epidemiology in the UK. Using the infection model in combination with a surveillance-like stochastic observation process we generated a range of possible RSV and Influenza trajectories and then used Markov Chain Monte Carlo (MCMC) methods to back-infer parameters including those describing competition. We find that in most scenarios both the strength and duration of RSV and Influenza interaction could be estimated from the simulated surveillance data reasonably well. However, the robustness of inference declined towards the extremes of the plausible parameter ranges, with misleading results. It was for instance not possible to tell the difference between low/moderate interaction and no interaction. In conclusion, our results illustrate that in a plausible parameter range, the strength of RSV and Influenza interaction can be estimated from a single season of high-quality surveillance data but also highlights the importance to test parameter identifiability a priori in such situations.
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Affiliation(s)
- Naomi R Waterlow
- Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, UK.
| | - Stefan Flasche
- Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, UK
| | - Amanda Minter
- Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, UK
| | - Rosalind M Eggo
- Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, UK
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13
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To T, Zhang K, Maguire B, Terebessy E, Fong I, Parikh S, Zhu J, Su Y. UV, ozone, and COVID-19 transmission in Ontario, Canada using generalised linear models. ENVIRONMENTAL RESEARCH 2021; 194:110645. [PMID: 33359457 PMCID: PMC7787508 DOI: 10.1016/j.envres.2020.110645] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 12/16/2020] [Accepted: 12/17/2020] [Indexed: 05/20/2023]
Abstract
BACKGROUND Quantifying the impact of environmental factors on COVID-19 transmission is crucial in preventing more cases. Ultraviolet (UV) radiation and ozone (O3) have reported antimicrobial properties but few studies have examined associations with community infectivity of COVID-19. Research suggests UV light can be preventative while the effect of O3 is contested. We sought to determine the relationship between UV, O3, and COVID-19 incidence in Ontario, Canada. METHODS In our time series analyses, we calculated daily incidence rates and reproductive number (Rt) from 34,975 cases between January and June 2020 across 34 Ontario Public Health Units. We used generalised linear models, adjusting for potential confounders, to calculate point estimates (PE) and 95% confidence intervals (CI) for UV and O3. Analyses were further stratified by age groups and outbreaks at institutions versus community. RESULTS We found that 1-week averaged UV was significantly associated with a 13% decrease (95% CI: 0.80-0.96) in overall COVID-19 Rt, per unit increase. A negative association with UV was also significant among community outbreaks (PE: 0.88, 95% CI: 0.81-0.96) but not institutional outbreaks (PE: 0.94, 95% CI: 0.85-1.03). A positive association of O3 with COVID-19 incidence is strongly suggested among institutional outbreak cases (PE: 1.06, 95% CI: 1.00-1.13). CONCLUSION Our study found evidence to support the hypothesis that higher UV reduced transmission of COVID-19 and some evidence that ground-level O3 positively influenced COVID-19 transmission. Setting of infection should be strongly considered as a factor in future research. UV and O3 may explain some of COVID-19's seasonal behaviour.
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Affiliation(s)
- Teresa To
- Child Health Evaluative Sciences, Research Institute, The Hospital for Sick Children, Toronto, ON, Canada; Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada.
| | - Kimball Zhang
- Child Health Evaluative Sciences, Research Institute, The Hospital for Sick Children, Toronto, ON, Canada
| | - Bryan Maguire
- Biostatistics, Design and Analysis, Research Institute, The Hospital for Sick Children, Toronto, ON, Canada
| | - Emilie Terebessy
- Child Health Evaluative Sciences, Research Institute, The Hospital for Sick Children, Toronto, ON, Canada
| | - Ivy Fong
- Child Health Evaluative Sciences, Research Institute, The Hospital for Sick Children, Toronto, ON, Canada
| | - Supriya Parikh
- Biostatistics, Design and Analysis, Research Institute, The Hospital for Sick Children, Toronto, ON, Canada
| | - Jingqin Zhu
- Child Health Evaluative Sciences, Research Institute, The Hospital for Sick Children, Toronto, ON, Canada
| | - Yushan Su
- Air Monitoring and Modelling Section, Ontario Ministry of the Environment, Conservation and Parks, Toronto, ON, Canada
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14
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Brand SP, Munywoki P, Walumbe D, Keeling MJ, Nokes DJ. Reducing respiratory syncytial virus (RSV) hospitalization in a lower-income country by vaccinating mothers-to-be and their households. eLife 2020; 9:47003. [PMID: 32216871 PMCID: PMC7556875 DOI: 10.7554/elife.47003] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 03/26/2020] [Indexed: 01/15/2023] Open
Abstract
Respiratory syncytial virus is the leading cause of lower respiratory tract infection among infants. RSV is a priority for vaccine development. In this study, we investigate the potential effectiveness of a two-vaccine strategy aimed at mothers-to-be, thereby boosting maternally acquired antibodies of infants, and their household cohabitants, further cocooning infants against infection. We use a dynamic RSV transmission model which captures transmission both within households and communities, adapted to the changing demographics and RSV seasonality of a low-income country. Model parameters were inferred from past RSV hospitalisations, and forecasts made over a 10-year horizon. We find that a 50% reduction in RSV hospitalisations is possible if the maternal vaccine effectiveness can achieve 75 days of additional protection for newborns combined with a 75% coverage of their birth household co-inhabitants (~7.5% population coverage).
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Affiliation(s)
- Samuel Pc Brand
- Zeeman Institute of Systems Biology and Infectious Disease Research (SBIDER), University of Warwick, Warwick, United Kingdom.,School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Patrick Munywoki
- Epidemiology and Demography Department, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - David Walumbe
- Epidemiology and Demography Department, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Matthew J Keeling
- Zeeman Institute of Systems Biology and Infectious Disease Research (SBIDER), University of Warwick, Warwick, United Kingdom.,School of Life Sciences, University of Warwick, Coventry, United Kingdom.,Mathematics Institute, University of Warwick, Coventry, United Kingdom
| | - David James Nokes
- Zeeman Institute of Systems Biology and Infectious Disease Research (SBIDER), University of Warwick, Warwick, United Kingdom.,School of Life Sciences, University of Warwick, Coventry, United Kingdom.,Epidemiology and Demography Department, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
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15
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Comparative Therapeutic Potential of ALX-0171 and Palivizumab against Respiratory Syncytial Virus Clinical Isolate Infection of Well-Differentiated Primary Pediatric Bronchial Epithelial Cell Cultures. Antimicrob Agents Chemother 2020; 64:AAC.02034-19. [PMID: 31767728 DOI: 10.1128/aac.02034-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 11/20/2019] [Indexed: 01/09/2023] Open
Abstract
Respiratory syncytial virus (RSV) causes severe lower respiratory tract infections in young infants. There are no RSV-specific treatments available. Ablynx has been developing an anti-RSV F-specific nanobody, ALX-0171. To characterize the therapeutic potential of ALX-0171, we exploited our well-differentiated primary pediatric bronchial epithelial cell (WD-PBEC)/RSV infection model, which replicates several hallmarks of RSV disease in vivo Using 2 clinical isolates (BT2a and Memphis 37), we compared the therapeutic potential of ALX-0171 with that of palivizumab, which is currently prescribed for RSV prophylaxis in high-risk infants. ALX-0171 treatment (900 nM) at 24 h postinfection reduced apically released RSV titers to near or below the limit of detection within 24 h for both strains. Progressively lower doses resulted in concomitantly diminished RSV neutralization. ALX-0171 was approximately 3-fold more potent in this therapeutic RSV/WD-PBEC model than palivizumab (mean 50% inhibitory concentration [IC50] = 346.9 to 363.6 nM and 1,048 to 1,090 nM for ALX-0171 and palivizumab, respectively), irrespective of the clinical isolate. The number of viral genomic copies (GC) was determined by quantitative reverse transcription-PCR (RT-qPCR), and the therapeutic effect of ALX-0171 treatment at 300 and 900 nM was found to be considerably lower and the number of GCs reduced only moderately (0.62 to 1.28 log10 copies/ml). Similar findings were evident for palivizumab. Therefore, ALX-0171 was very potent at neutralizing RSV released from apical surfaces but had only a limited impact on virus replication. The data indicate a clear disparity between viable virus neutralization and GC viral load, the latter of which does not discriminate between viable and neutralized RSV. This report validates the RSV/WD-PBEC model for the preclinical evaluation of RSV antivirals.
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16
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Ali A, Lopardo G, Scarpellini B, Stein RT, Ribeiro D. Systematic review on respiratory syncytial virus epidemiology in adults and the elderly in Latin America. Int J Infect Dis 2020; 90:170-180. [PMID: 31669592 PMCID: PMC7110494 DOI: 10.1016/j.ijid.2019.10.025] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 10/17/2019] [Accepted: 10/18/2019] [Indexed: 12/31/2022] Open
Abstract
OBJECTIVES The present study provides a comprehensive review of the recently published data on RSV epidemiology in adults and the elderly in Latin America. METHODS A systematic literature search was carried out in Medline, Scielo, Lilacs, and Cochrane Library. The search strategy aimed at retrieving studies focusing on RSV prevalence, burden, risk factors, and the routine clinical practice in the prevention and management of RSV infections in Latin American countries. Only articles published between January 2011 and December 2017 were considered. RESULTS Eighteen studies were included. Percentages of RSV detection varied highly across included studies for adult subjects with respiratory infections (0% to 77.9%), influenza-like illness (1.0% to 16.4%) and community-acquired pneumonia (1.3% to 13.5%). Considerable percentages of hospitalization were reported for RSV-infected adults with influenza-like illness (40.9% and 69.9%) and community-acquired pneumonia (91.7%). CONCLUSIONS Recent RSV data regarding adult populations in Latin America are scarce. RSV was documented as a cause of illness in adults and the elderly, being identified in patients with acute respiratory infections, influenza-like illness and community-acquired pneumonia. The studies suggest that RSV infections may be a significant cause of hospitalization in adult populations in Latin America, including younger adults.
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Affiliation(s)
- Abraham Ali
- Fundación Neumológica Colombiana, Carrera 13B # 161- 85 Piso 2, Postal Code 110131, Bogotá, Colombia.
| | - Gustavo Lopardo
- Department of Infectious Diseases at FUNCEI and Hospital Bernardo Houssay, French 3085, (1425) Buenos Aires, Argentina.
| | - Bruno Scarpellini
- Real World Evidence Department, Medical Affairs Latin America, Janssen Cilag Farmacêutica, Avenida Presidente Juscelino Kubitschek, 2041 - Vila Nova Conceição, 04543-011, São Paulo, Brazil.
| | - Renato T. Stein
- Pontifícia Universidade Católica do RGS (PUCRS), ReSViNET Executive Committee member, Centro Clinico PUCRS, Av. Ipiranga, 6690, conj.420. Porto Alegre, RS, CEP 90610-000, Brazil
| | - Diogo Ribeiro
- CTI Clinical Trial & Consulting Services, Rua Tierno Galvan, Torre 3, Piso 16, 1070-274 Lisboa, Portugal.
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17
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Baker RE, Mahmud AS, Wagner CE, Yang W, Pitzer VE, Viboud C, Vecchi GA, Metcalf CJE, Grenfell BT. Epidemic dynamics of respiratory syncytial virus in current and future climates. Nat Commun 2019; 10:5512. [PMID: 31797866 PMCID: PMC6892805 DOI: 10.1038/s41467-019-13562-y] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 11/14/2019] [Indexed: 12/14/2022] Open
Abstract
A key question for infectious disease dynamics is the impact of the climate on future burden. Here, we evaluate the climate drivers of respiratory syncytial virus (RSV), an important determinant of disease in young children. We combine a dataset of county-level observations from the US with state-level observations from Mexico, spanning much of the global range of climatological conditions. Using a combination of nonlinear epidemic models with statistical techniques, we find consistent patterns of climate drivers at a continental scale explaining latitudinal differences in the dynamics and timing of local epidemics. Strikingly, estimated effects of precipitation and humidity on transmission mirror prior results for influenza. We couple our model with projections for future climate, to show that temperature-driven increases to humidity may lead to a northward shift in the dynamic patterns observed and that the likelihood of severe outbreaks of RSV hinges on projections for extreme rainfall.
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Affiliation(s)
- Rachel E Baker
- Princeton Environmental Institute, Princeton University, Princeton, NJ, USA.
| | - Ayesha S Mahmud
- Planetary Health Alliance, Harvard University, Cambridge, MA, USA.,Department of Demography, University of California, Berkeley, Berkeley, CA, USA
| | - Caroline E Wagner
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA
| | - Wenchang Yang
- Department of Geosciences, Princeton University, Princeton, NJ, USA
| | - Virginia E Pitzer
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA
| | - Cecile Viboud
- Division of International Epidemiology and Population Studies, Fogarty International Center, National Institutes of Health, Bethesda, MD, USA
| | - Gabriel A Vecchi
- Princeton Environmental Institute, Princeton University, Princeton, NJ, USA.,Department of Geosciences, Princeton University, Princeton, NJ, USA
| | - C Jessica E Metcalf
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA.,Woodrow Wilson School of Public and International Affairs, Princeton University, Princeton, NJ, USA
| | - Bryan T Grenfell
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA.,Division of International Epidemiology and Population Studies, Fogarty International Center, National Institutes of Health, Bethesda, MD, USA.,Woodrow Wilson School of Public and International Affairs, Princeton University, Princeton, NJ, USA
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18
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Mahikul W, J. White L, Poovorawan K, Soonthornworasiri N, Sukontamarn P, Chanthavilay P, F. Medley G, Pan-ngum W. Modeling household dynamics on Respiratory Syncytial Virus (RSV). PLoS One 2019; 14:e0219323. [PMID: 31287832 PMCID: PMC6615606 DOI: 10.1371/journal.pone.0219323] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Accepted: 06/20/2019] [Indexed: 11/19/2022] Open
Abstract
Respiratory Syncytial Virus (RSV) is the most common cause of respiratory tract infection in infants and children and shows increasing trend among elderly people worldwide. In many developing country settings, population and household structures have gone through some significant changes in the past decades, namely fewer births, more elderly population, and smaller household size but more RSV high-risk individuals. These dynamics have been captured in a mathematical model with RSV transmission dynamics to predict the disease burden on the detailed population for future targeted interventions. The population and disease dynamics model was constructed and tested against the hospitalization data for Acute Lower Respiratory Tract Infection due to RSV in rural Thai settings between 2005 and 2011. The proportion of extended families is predicted to increase by about 10% from 2005 to 2020, especially for those with elderly population, while the classic nuclear family type (with adults and children) will decline by about 10%. For RSV, infections from extended family type (approximately 60% of all household types) have majorly contributed to the force of infection (FOI). While the model predicted the increase of FOI from the extended family by 15% from 2005 to 2020, the FOI contributed by other household types would be either stable or decrease in the same time period. RSV incidence rate is predominantly high among babies (92.2%) and has been predicted to decrease slightly over time (from 940 to 864 cases per 100,000 population by 2020), while the incidence rates among children and elderly people may remain steadily low over the same period. However, the estimated incidence rates among elderly people were twice than those in children. The model predicts that approximately 60% of FOI for RSV will come from members of the extended family type. The incidence rate of RSV among children and elderly in extended families was about 20 times lower than that in infants and the trend is steady. Targeted intervention strategies, such as health education in some specific groups and targeted vaccination, may be considered, with the focus on extended family type. Target interventions on babies can lessen the transmission to children and elderly especially when transmission within households of extended family type is high.
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Affiliation(s)
- Wiriya Mahikul
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Lisa J. White
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Kittiyod Poovorawan
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | | | | | - Phetsavanh Chanthavilay
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Institute of Research and Education Development, UHS, Vientiane, Lao PDR
| | - Graham F. Medley
- Centre for Mathematical Modelling of Infectious Disease & Department of Global Health and Development, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Wirichada Pan-ngum
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
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19
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Vliora C, Papadakis V, Doganis D, Tourkantoni N, Paisiou A, Kottaridi C, Kourlamba G, Zaoutis T, Kosmidis H, Kattamis A, Polychronopoulou S, Goussetis E, Giannouli G, Syridou G, Priftis K, Papaevangelou V. A prospective study on the epidemiology and clinical significance of viral respiratory infections among pediatric oncology patients. Pediatr Hematol Oncol 2019; 36:173-186. [PMID: 31215284 DOI: 10.1080/08880018.2019.1613462] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Respiratory infections in oncology are both common and potentially severe. However, there is still a gap in the literature, regarding the epidemiology of viral respiratory infections in children with cancer. We prospectively enrolled 224 patients, from September 2012 to August 2015. The cohort included children with hematologic or solid malignancies receiving chemotherapy, or undergoing hemopoietic stem cell transplantation, outpatients/inpatients exhibiting signs/symptoms of febrile/afebrile upper/lower respiratory infection. Viral infection was diagnosed by detection of ≥1 viruses from a sample at time of enrollment, using the CLART® PneumoVir kit (GENOMICA, Spain). Α detailed questionnaire including demographics and medical history was also completed. Samples were processed in batches, results were communicated as soon as they became available. Children recruited in whom no virus was detected composed the no virus detected group. Viral prevalence was 38.4% in children presenting with respiratory illness. A single virus was found in 30.4%, with RSV being the most frequent. Viral coinfections were detected in 8%. Children with viral infection were more likely to be febrile upon enrollment and to present with lower respiratory signs/symptoms. They had longer duration of illness and they were more likely to receive antibiotics/antifungals. Only 22% of children with influenza received oseltamivir. Mortality was low (2.7%), however, pediatric intensive care unit (PICU) admission and death were correlated with virus detection. In our study mortality was low and PICU admission was related to virus identification. Further research is needed to clarify whether antibiotics in virus-proven infection are of value and underline the importance of oseltamivir's timely administration in influenza.
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Affiliation(s)
- Christianna Vliora
- a Third Department of Pediatrics , National and Kapodistrian University of Athens, "ATTIKON" University Hospital , Athens , Greece
| | - Vassilios Papadakis
- b Department of Pediatric Hematology-Oncology , Athens , Greece , "Aghia Sofia" Children's Hospital
| | - Dimitrios Doganis
- c Oncology Department , " P&A Kyriakou" Children's Hospital , Athens , Greece
| | - Natalia Tourkantoni
- d Hematology-Oncology Unit, First Department of Pediatrics , National and Kapodistrian University of Athens, "Aghia Sofia" Children's Hospital , Athens , Greece
| | - Anna Paisiou
- e Stem Cell Transplant Unit , Aghia Sofia Children's Hospital , Athens , Greece
| | | | - Georgia Kourlamba
- g The Stavros Niarchos Foundation-Collaborative Center for Clinical Epidemiology and Outcomes Research (CLEO), First and Second Departments of Pediatrics, National and Kapodistrian University of Athens , Athens , Greece
| | - Theoklis Zaoutis
- g The Stavros Niarchos Foundation-Collaborative Center for Clinical Epidemiology and Outcomes Research (CLEO), First and Second Departments of Pediatrics, National and Kapodistrian University of Athens , Athens , Greece
| | - Helen Kosmidis
- c Oncology Department , " P&A Kyriakou" Children's Hospital , Athens , Greece
| | - Antonis Kattamis
- d Hematology-Oncology Unit, First Department of Pediatrics , National and Kapodistrian University of Athens, "Aghia Sofia" Children's Hospital , Athens , Greece
| | - Sophia Polychronopoulou
- b Department of Pediatric Hematology-Oncology , Athens , Greece , "Aghia Sofia" Children's Hospital
| | - Evgenios Goussetis
- e Stem Cell Transplant Unit , Aghia Sofia Children's Hospital , Athens , Greece
| | - Georgia Giannouli
- a Third Department of Pediatrics , National and Kapodistrian University of Athens, "ATTIKON" University Hospital , Athens , Greece
| | - Garyfallia Syridou
- a Third Department of Pediatrics , National and Kapodistrian University of Athens, "ATTIKON" University Hospital , Athens , Greece
| | - Kostas Priftis
- a Third Department of Pediatrics , National and Kapodistrian University of Athens, "ATTIKON" University Hospital , Athens , Greece
| | - Vassiliki Papaevangelou
- a Third Department of Pediatrics , National and Kapodistrian University of Athens, "ATTIKON" University Hospital , Athens , Greece
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20
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Yamagami H, Kimura H, Hashimoto T, Kusakawa I, Kusuda S. Detection of the Onset of the Epidemic Period of Respiratory Syncytial Virus Infection in Japan. Front Public Health 2019; 7:39. [PMID: 30931290 PMCID: PMC6425940 DOI: 10.3389/fpubh.2019.00039] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 02/14/2019] [Indexed: 11/13/2022] Open
Abstract
Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract infection in young children worldwide. An annual epidemic of RSV infection generally begins around autumn, reaching a peak at the end of year in Japan, but in 2017 it started in early July and peaked in September. As the onset timing of RSV season varies, it is important to detect the beginning of an epidemic, to enable the implementation of preventive measures. However, there are currently no specified criteria or methods to determine the onset of RSV season in a timely manner. Therefore, we developed a model to detect the epidemic onset, based on data from the Infectious Diseases Weekly Report from 2012 to 2017. The 47 prefectures of Japan span 11 climate zones, which affect the timing of epidemic onset. Therefore, the onset of RSV season was assessed separately in each prefecture. Non-linear regression analysis was performed to generate a mathematical model of the annual epidemic cycle for each prefecture. A search index was used to determine the onset of RSV season, which was estimated using the number of RSV reports per week within an epidemic period (RSV-reports/w) and the number of reported cases included within an epidemic period relative to the total number of RSV reports (capture rate). A number of RSV-reports/w, which was used as a threshold (a number at onset line) to determine the condition of the onset of RSV season, was then estimated based on the search index. The mean number at the onset of RSV season for 47 prefectures was 29.7 reports/week (median 21.0, range 6.0-121.0 reports/ week). The model also showed that the onset of RSV season in 2017 was more than 1 month earlier than the previous year. In conclusion, the model detected epidemic cycles and their onset conditions in all prefectures, despite the 11 climate zones of Japan. The results are expected to contribute to infant medical care by allowing medical personnel to take preventive measures promptly at the beginning of the epidemic RSV season.
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Affiliation(s)
| | - Hirokazu Kimura
- Department of Health Science, Gunma Paz University Graduate School of Health Science, Gunma, Japan
| | | | - Isao Kusakawa
- Department of Pediatrics, St. Luke's International Hospital, Tokyo, Japan
| | - Satoshi Kusuda
- Department of Pediatrics, Faculty of Medicine, Kyorin University, Tokyo, Japan
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21
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Olawoyin O, Kribs C. Invasion reproductive numbers for discrete-time models. Infect Dis Model 2019; 4:44-72. [PMID: 31016273 PMCID: PMC6468161 DOI: 10.1016/j.idm.2019.03.002] [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: 10/25/2018] [Revised: 03/16/2019] [Accepted: 03/29/2019] [Indexed: 12/02/2022] Open
Abstract
Although invasion reproductive numbers (IRNs) are utilized frequently in continuous-time models with multiple interacting pathogens, they are yet to be explored in discrete-time systems. Here, we extend the concept of IRNs to discrete-time models by showing how to calculate them for a set of two-pathogen SIS models with coinfection. In our exploration, we address how sequencing events impacts the basic reproductive number (BRN) and IRN. As an illustrative example, our models are applied to rhinovirus and respiratory syncytial virus co-circulation. Results show that while the BRN is unaffected by variations in the order of events, the IRN differs. Furthermore, our models predict copersistence of multiple pathogen strains under cross-immunity, which is atypical of analogous continuous-time models. This investigation shows that sequencing events has important consequences for the IRN and can drastically alter competition dynamics.
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22
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Reuter SE, Evans AM, Ward MB. Reducing Palivizumab Dose Requirements Through Rational Dose Regimen Design. CPT-PHARMACOMETRICS & SYSTEMS PHARMACOLOGY 2018; 8:26-33. [PMID: 30426719 PMCID: PMC6363066 DOI: 10.1002/psp4.12364] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 10/09/2018] [Indexed: 02/02/2023]
Abstract
Palivizumab for respiratory syncytial virus (RSV) immunoprophylaxis in premature infants poses a significant economic challenge. Although standard dosing of palivizumab results in unnecessary drug accumulation without additional clinical benefit, some clinicians have moved outside of evidence‐based practice by implementing untested dose modifications, potentially jeopardizing efficacy. Using an industry‐developed population pharmacokinetic model, this study evaluated the previously published alternate dosing regimens and developed a revised regimen that minimizes palivizumab dose requirements while maintaining established therapeutic concentrations. All published dose modifications resulted in unacceptably high proportions of infants not attaining minimum protective concentrations, compromising efficacy. Through intelligent dose regimen design, a clinically practical palivizumab regimen was devised that reduces drug use by 25%, while enabling a greater proportion of infants attaining early season target concentrations, particularly those at greatest risk of the consequences of RSV infection. This novel regimen has the potential to substantially change clinical practice and increase drug availability.
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Affiliation(s)
- Stephanie E Reuter
- School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - Allan M Evans
- School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - Michael B Ward
- School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia, Australia
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23
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Santos DADS, Azevedo PVD, Olinda RAD, Santos CACD, Souza AD, Sette DM, Souza PMD. The relationship of climate variables in the prevalence of acute respiratory infection in children under two years old in Rondonópolis-MT, Brazil. CIENCIA & SAUDE COLETIVA 2017; 22:3711-3722. [PMID: 29211176 DOI: 10.1590/1413-812320172211.28322015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 04/04/2016] [Indexed: 11/21/2022] Open
Abstract
It is estimated that approximately 30% of childhood diseases can be attributed to environmental factors and 40% involve children under the age of five years old, representing about 10% of world population. This study aimed to analyze the relationship of climate variables in the prevalence of acute respiratory infection (ARI) in children under two years old, in Rondonopolis-MT, from 1999 to 2014. It was used a cross-sectional study with a quantitative and a descriptive approach with meteorological teaching and research data from the database from the health information system. For statistical analysis, it adjusted the negative binomial model belonging to the class of generalized linear models, adopting a significance level of 5%, based on the statistical platform R. The average number of cases of ARI decreases at approximately by 7.9% per degree centigrade increase above the average air temperature and decrease about 1.65% per 1% increase over the average air relative humidity. Already, the rainfall not associated with these cases. It is the interdisciplinary team refocus practical actions to assist in the control and reduction of ARI significant numbers in primary health care, related climate issues in children.
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Affiliation(s)
- Débora Aparecida da Silva Santos
- Curso de Enfermagem, Instituto de Ciências Exatas e Naturais, Universidade Federal de Mato Grosso, Campus Universitário de Rondonópolis. Rodovia Rondonópolis-Guiratinga Km 06, BR 364. 78700-000 Rondonópolis MT Brasil.
| | | | | | | | - Amaury de Souza
- Departamento de Física, Centro de Ciências Exatas e Tecnologia, Universidade Federal de Mato Grosso do Sul. Campo Grande MS Brasil
| | - Denise Maria Sette
- Universidade Federal de Mato Grosso, Campus Universitário de Rondonópolis. Rondonópolis MT Brasil
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24
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Anderson AJ, Snelling TL, Moore HC, Blyth CC. Advances in Vaccines to Prevent Viral Respiratory Illnesses in Children. Paediatr Drugs 2017; 19:523-531. [PMID: 28808938 DOI: 10.1007/s40272-017-0257-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Childhood vaccination has played a critical role in the reduction of morbidity and mortality from communicable diseases, including specific respiratory pathogens. Acute lower respiratory infection (ALRI) of both bacterial and viral aetiology continues to impact global child health. Key bacterial pathogens including Streptococcus pneumoniae and Haemophilus influenza type b are specifically targeted with current vaccination programmes, while at present there are less effective strategies for the prevention of viral disease. Influenza vaccines, including both live attenuated intranasal vaccines and inactivated influenza vaccines, are limited by seasonal strain variation and unsustained immunity. Research into the development of a universal influenza vaccine is ongoing; potential targets are the conserved regions of the virus such as the M2e antigen and hemagglutinin stalk. Respiratory syncytial virus (RSV) and parainfluenza virus 3 (PIV3) are the viral pathogens most commonly causing ALRI in children, particularly the infant population. Currently, no vaccine exists for either virus. Over the last decade, promising advances have been made. Protection of neonates via maternal RSV immunisation is being assessed in a phase III clinical trial, with many other candidates for RSV and PIV3 at less advanced stages of development.
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Affiliation(s)
- Aleisha J Anderson
- Department of Infectious Diseases, Princess Margaret Hospital, Roberts Rd, Subiaco, WA, Australia
| | - Tom L Snelling
- Department of Infectious Diseases, Princess Margaret Hospital, Roberts Rd, Subiaco, WA, Australia.,Wesfarmers Centre for Vaccines and Infectious Diseases, Telethon Kids Institute, Roberts Rd, Subiaco, WA, Australia
| | - Hannah C Moore
- Wesfarmers Centre for Vaccines and Infectious Diseases, Telethon Kids Institute, Roberts Rd, Subiaco, WA, Australia
| | - Christopher C Blyth
- Department of Infectious Diseases, Princess Margaret Hospital, Roberts Rd, Subiaco, WA, Australia. .,Wesfarmers Centre for Vaccines and Infectious Diseases, Telethon Kids Institute, Roberts Rd, Subiaco, WA, Australia. .,Discipline of Paediatrics, School of Medicine, Princess Margaret Hospital, University of Western Australia, Roberts Rd, Subiaco, WA, Australia. .,PathWest Laboratory Medicine WA, Department of Microbiology, QEII Medical Centre, Nedlands, WA, Australia.
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25
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Hogan AB, Campbell PT, Blyth CC, Lim FJ, Fathima P, Davis S, Moore HC, Glass K. Potential impact of a maternal vaccine for RSV: A mathematical modelling study. Vaccine 2017; 35:6172-6179. [PMID: 28967522 DOI: 10.1016/j.vaccine.2017.09.043] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 08/14/2017] [Accepted: 09/13/2017] [Indexed: 11/16/2022]
Abstract
Respiratory syncytial virus (RSV) is a major cause of respiratory morbidity and one of the main causes of hospitalisation in young children. While there is currently no licensed vaccine for RSV, a vaccine candidate for pregnant women is undergoing phase 3 trials. We developed a compartmental age-structured model for RSV transmission, validated using linked laboratory-confirmed RSV hospitalisation records for metropolitan Western Australia. We adapted the model to incorporate a maternal RSV vaccine, and estimated the expected reduction in RSV hospitalisations arising from such a program. The introduction of a vaccine was estimated to reduce RSV hospitalisations in Western Australia by 6-37% for 0-2month old children, and 30-46% for 3-5month old children, for a range of vaccine effectiveness levels. Our model shows that, provided a vaccine is demonstrated to extend protection against RSV disease beyond the first three months of life, a policy using a maternal RSV vaccine could be effective in reducing RSV hospitalisations in children up to six months of age, meeting the objective of a maternal vaccine in delaying an infant's first RSV infection to an age at which severe disease is less likely.
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Affiliation(s)
- Alexandra B Hogan
- Research School of Population Health, The Australian National University, 62 Mills Rd, The Australian National University, Acton ACT 2601, Australia.
| | - Patricia T Campbell
- Doherty Epidemiology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Level 5, 792 Elizabeth St, Melbourne, Victoria 3000, Australia; Infection and Immunity, Murdoch Childrens Research Institute, Royal Children's Hospital, Flemington Rd, Parkville 3052, Victoria, Australia
| | - Christopher C Blyth
- School of Medicine, University of Western Australia, Princess Margaret Hospital for Children, Roberts Rd, Subiaco, Perth, WA 6008, Australia; Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, The University of Western Australia, 100 Roberts Rd, Subiaco, Perth, WA 6008, Australia; Department of Infectious Disease and PathWest Department of Microbiology, Princess Margaret Hospital for Children, Roberts Rd, Subiaco, WA 6008, Australia
| | - Faye J Lim
- Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, The University of Western Australia, 100 Roberts Rd, Subiaco, Perth, WA 6008, Australia
| | - Parveen Fathima
- Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, The University of Western Australia, 100 Roberts Rd, Subiaco, Perth, WA 6008, Australia
| | - Stephanie Davis
- Research School of Population Health, The Australian National University, 62 Mills Rd, The Australian National University, Acton ACT 2601, Australia
| | - Hannah C Moore
- Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, The University of Western Australia, 100 Roberts Rd, Subiaco, Perth, WA 6008, Australia
| | - Kathryn Glass
- Research School of Population Health, The Australian National University, 62 Mills Rd, The Australian National University, Acton ACT 2601, Australia
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26
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Smith RJ, Hogan AB, Mercer GN. Unexpected Infection Spikes in a Model of Respiratory Syncytial Virus Vaccination. Vaccines (Basel) 2017; 5:vaccines5020012. [PMID: 28524109 PMCID: PMC5492009 DOI: 10.3390/vaccines5020012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 02/06/2017] [Accepted: 05/15/2017] [Indexed: 12/04/2022] Open
Abstract
Respiratory Syncytial Virus (RSV) is an acute respiratory infection that infects millions of children and infants worldwide. Recent research has shown promise for the development of a vaccine, with a range of vaccine types now in clinical trials or preclinical development. We extend an existing mathematical model with seasonal transmission to include vaccination. We model vaccination both as a continuous process, applying the vaccine during pregnancy, and as a discrete one, using impulsive differential equations, applying pulse vaccination. We develop conditions for the stability of the disease-free equilibrium and show that this equilibrium can be destabilised under certain extreme conditions, even with 100% coverage using an (unrealistic) vaccine. Using impulsive differential equations and introducing a new quantity, the impulsive reproduction number, we showed that eradication could be acheived with 75% coverage, while 50% coverage resulted in low-level oscillations. A vaccine that targets RSV infection has the potential to significantly reduce the overall prevalence of the disease, but appropriate coverage is critical.
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Affiliation(s)
- Robert J Smith
- Department of Mathematics and Faculty of Medicine, The University of Ottawa, 585 King Edward Ave, Ottawa, ON K1N 6N5, Canada.
| | - Alexandra B Hogan
- Department of Infectious Disease Epidemiology, Imperial College London, St Mary's Campus, London W2 1PG, UK and Research School of Population Health, The Australian National University, Canberra 2601, Australia.
| | - Geoffry N Mercer
- Research School of Population Health, The Australian National University, Canberra 2601, Australia.
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27
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Cangiano G, Nenna R, Frassanito A, Evangelisti M, Nicolai A, Scagnolari C, Pierangeli A, Antonelli G, Papoff P, Petrarca L, Capocaccia P, Moretti C, Midulla F. Bronchiolitis: Analysis of 10 consecutive epidemic seasons. Pediatr Pulmonol 2016; 51:1330-1335. [PMID: 27228123 PMCID: PMC7167938 DOI: 10.1002/ppul.23476] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 04/12/2016] [Accepted: 04/18/2016] [Indexed: 11/12/2022]
Abstract
Bronchiolitis is the leading cause of hospitalization in infants under 12 months. Our aims were to analyze epidemiological characteristics of infants with bronchiolitis over 10 consecutive seasons and to evaluate whether there are any clinical differences between infants hospitalized for bronchiolitis during epidemic peak months and infants in non-peak months. We enrolled consecutive enrolled 723 previously healthy term infants hospitalized at the Paediatric Emergency Department, "Sapienza" University of Rome over the period 2004-2014. Fourteen respiratory viruses were detected from nasopharyngeal aspirates by molecular methods. Clinical and demographic data were extracted from clinical charts. Viruses were detected in 351 infants (48.5%): RSV in 234 (32.4%), RV in 44 (6.1%), hBoV in 11 (1.5%), hMPV in 12 (1.6%), co-infections in 39 (5.4%), and other viruses in 11 (1.5%). Analyzing the 10 epidemic seasons, we found higher incidence for bronchiolitis every 4 years with a peak during the months December-January. Infants hospitalized during peak months had lower family history for asthma (P = 0.003), more smoking mothers during pregnancy (P = 0.036), were slightly higher breastfed (0.056), had lower number of blood eosinophils (P = 0.015) and had a higher clinical severity score (P = 0.017). RSV was detected mostly during peak months, while RV was equally distributed during the seasons. We found some variations in bronchiolitis incidence during epidemics, and discriminative characteristics in infants hospitalized for bronchiolitis during peak months and in non-peak months, that might reflect two different populations of children. Pediatr Pulmonol. 2016;51:1330-1335. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Giulia Cangiano
- Department of Pediatrics and Infantile Neuropsychiatry“Sapienza” University of RomeV.le Regina Elena 324Rome 00161Italy
| | - Raffaella Nenna
- Department of Pediatrics and Infantile Neuropsychiatry“Sapienza” University of RomeV.le Regina Elena 324Rome 00161Italy
| | - Antonella Frassanito
- Department of Pediatrics and Infantile Neuropsychiatry“Sapienza” University of RomeV.le Regina Elena 324Rome 00161Italy
| | - Melania Evangelisti
- Department of Pediatrics and Infantile Neuropsychiatry“Sapienza” University of RomeV.le Regina Elena 324Rome 00161Italy
| | - Ambra Nicolai
- Department of Pediatrics and Infantile Neuropsychiatry“Sapienza” University of RomeV.le Regina Elena 324Rome 00161Italy
| | - Carolina Scagnolari
- Department of Molecular MedicineVirology Laboratory, “Sapienza” University of RomeRomeItaly
| | - Alessandra Pierangeli
- Department of Molecular MedicineVirology Laboratory, “Sapienza” University of RomeRomeItaly
| | - Guido Antonelli
- Department of Molecular MedicineVirology Laboratory, “Sapienza” University of RomeRomeItaly
| | - Paola Papoff
- Department of Pediatrics and Infantile Neuropsychiatry“Sapienza” University of RomeV.le Regina Elena 324Rome 00161Italy
| | - Laura Petrarca
- Department of Pediatrics and Infantile Neuropsychiatry“Sapienza” University of RomeV.le Regina Elena 324Rome 00161Italy
| | - Paolo Capocaccia
- Department of Pediatrics and Infantile Neuropsychiatry“Sapienza” University of RomeV.le Regina Elena 324Rome 00161Italy
| | - Corrado Moretti
- Department of Pediatrics and Infantile Neuropsychiatry“Sapienza” University of RomeV.le Regina Elena 324Rome 00161Italy
| | - Fabio Midulla
- Department of Pediatrics and Infantile Neuropsychiatry“Sapienza” University of RomeV.le Regina Elena 324Rome 00161Italy
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28
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Characterizing the risk of respiratory syncytial virus in infants with older siblings: a population-based birth cohort study. Epidemiol Infect 2016; 145:266-271. [PMID: 27821195 DOI: 10.1017/s0950268816002545] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
From a population-based birth cohort of 245 249 children born in Western Australia during 1996-2005, we used linkage of laboratory and birth record datasets to obtain data including all respiratory syncytial virus (RSV) detections during infancy from a subcohort of 87 981 singleton children born in the Perth metropolitan area from 2000 to 2004. Using log binomial regression, we found that the risk of infant RSV detection increases with the number of older siblings, with those having ⩾3 older siblings experiencing almost three times the risk (relative risk 2·83, 95% confidence interval 2·46-3·26) of firstborn children. We estimate that 45% of the RSV detections in our subcohort were attributable to infection from an older sibling. The sibling effect was significantly higher for those infants who were younger during the season of peak risk (winter) than those who were older. Although older siblings were present in our cohort, they had very few RSV detections which could be temporally linked to an infant's infection. We conclude that RSV infection in older children leads to less severe symptoms but is nevertheless an important source of infant infection. Our results lend support to a vaccination strategy which includes family members in order to provide maximum protection for newborn babies.
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Bouzas ML, Oliveira JR, Fukutani KF, Borges IC, Barral A, Van der Gucht W, Wollants E, Van Ranst M, de Oliveira CI, Van Weyenbergh J, Nascimento-Carvalho CM. Respiratory syncytial virus a and b display different temporal patterns in a 4-year prospective cross-sectional study among children with acute respiratory infection in a tropical city. Medicine (Baltimore) 2016; 95:e5142. [PMID: 27741144 PMCID: PMC5072971 DOI: 10.1097/md.0000000000005142] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Respiratory syncytial virus (RSV) is one of the most common etiological agents of childhood respiratory infections globally. Information on seasonality of different antigenic groups is scarce. We aimed to describe the frequency, seasonality, and age of children infected by RSV antigenic groups A (RSVA) and B (RSVB) among children with ARI in a 4-year period.Children (6-23 months old) with respiratory infection for ≤7 days were enrolled in a prospective cross-sectional study, from September, 2009 to October, 2013, in Salvador, in a tropical region of Brazil. Upon recruitment, demographic, clinical data, and nasopharyngeal aspirates (NPA) were collected. A multiplex quantitative real-time polymerase chain reaction (RT-PCR) with a group-specific primer and probeset for RSVA and RSVB was used. Seasonal distribution of infection by RSV different antigenic groups was evaluated by Prais-Wisten regression.Of 560 cases, the mean age was 11.4 ± 4.5 months and there were 287 (51.3%) girls. Overall, RSV was detected in 139 (24.8%; 95% CI: 21.4%-28.5%) cases, RSVA in 74 (13.2%; 95% CI: 10.6%-16.2%) cases, and RSVB in 67 (12.0%; 95% CI: 9.5%-14.9%) cases. Two (0.4%; 95% CI: 0.06%-1.2%) cases had coinfection. RSVA frequency was 9.6%, 18.4%, 21.6%, and 3.1% in 2010, 2011, 2012, and 2013, respectively. RSVB frequency was 19.2%, 0.7%, 1.4%, and 35.4% in the same years. RSVA was more frequently found from August to January than February to July (18.2% vs. 6.4%, P < 0.001). RSVB was more frequently found (P < 0.001) between March and June (36.0%) than July to October (1.0%) or November to February (1.6%). RSVB infection showed seasonal distribution and positive association with humidity (P = 0.02) whereas RSVA did not. RSVA was more common among children ≥1-year-old (17.8% vs. 1.8%; P = 0.02), as opposed to RSVB (11.5% vs. 12.2%; P = 0.8).One quarter of patients had RSV infection. RSVA compromised more frequently children aged ≥1 year. RSVA predominated in 2011 and 2012 whereas RSVB predominated in 2010 and 2013. In regard to months, RSVA was more frequent from August to January whereas RSVB was more often detected between March and June. Markedly different monthly as well as yearly patterns for RSVA and RSVB reveal independent RSV antigenic groups' epidemics.
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Affiliation(s)
- Maiara L Bouzas
- Postgraduate Program in Health Sciences, Federal University of Bahia School of Medicine, Salvador, Bahia, Brazil Centro de Pesquisas Gonçalo Moniz (CPqGM), Fundação Oswaldo Cruz (FIOCRUZ), Salvador, Bahia, Brazil Department of Pathology, Federal University of Bahia School of Medicine, Salvador, Bahia, Brazil Department of Microbiology and Immunology, Laboratory for Clinical and Epidemiological Virology, Rega Institute for Medical Research, KU, Leuven, Belgium Department of Pediatrics, Federal University of Bahia School of Medicine, Salvador, Bahia, Brazil
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30
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Hogan AB, Glass K, Moore HC, Anderssen RS. Exploring the dynamics of respiratory syncytial virus (RSV) transmission in children. Theor Popul Biol 2016; 110:78-85. [PMID: 27155294 DOI: 10.1016/j.tpb.2016.04.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 04/12/2016] [Accepted: 04/18/2016] [Indexed: 10/21/2022]
Abstract
Respiratory syncytial virus (RSV) is the main cause of lower respiratory tract infections in children. Whilst highly seasonal, RSV dynamics can have either one-year (annual) or two-year (biennial) cycles. Furthermore, some countries show a 'delayed biennial' pattern, where the epidemic peak in low incidence years is delayed. We develop a compartmental model for RSV infection, driven by a seasonal forcing function, and conduct parameter space and bifurcation analyses to document parameter ranges that give rise to these different seasonal patterns. The model is sensitive to the birth rate, transmission rate, and seasonality parameters, and can replicate RSV dynamics observed in different countries. The seasonality parameter must exceed a threshold for the model to produce biennial cycles. Intermediate values of the birth rate produce the greatest delay in these biennial cycles, while the model reverts to annual cycles if the duration of immunity is too short. Finally, the existence of period doubling and period halving bifurcations suggests robust model dynamics, in agreement with the known regularity of RSV outbreaks. These findings help explain observed RSV data, such as regular biennial dynamics in Western Australia, and delayed biennial dynamics in Finland. From a public health perspective, our findings provide insight into the drivers of RSV transmission, and a foundation for exploring RSV interventions.
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Affiliation(s)
- Alexandra B Hogan
- National Centre for Epidemiology and Population Health, Building 62, Corner Mills and Eggleston Roads, The Australian National University, Canberra ACT 2601, Australia.
| | - Kathryn Glass
- National Centre for Epidemiology and Population Health, Building 62, Corner Mills and Eggleston Roads, The Australian National University, Canberra ACT 2601, Australia
| | - Hannah C Moore
- Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, The University of Western Australia, Western Australia, Australia
| | - Robert S Anderssen
- CSIRO Data61; Mathematical Sciences Institute, The Australian National University; Mathematics and Statistics, La Trobe University, Australia
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31
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Zhang M, Zhai R, Liu J, Guang H, Li B, Zhang S. Seasonal Variation of Blood Calcium Levels in Children Aged 1-10. J Clin Lab Anal 2016; 30:741-4. [PMID: 27061272 DOI: 10.1002/jcla.21931] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 11/22/2015] [Accepted: 12/08/2015] [Indexed: 11/05/2022] Open
Abstract
BACKGROUND In this study, the associations of seasons with blood calcium levels in children aged 1-10 have not been evaluated. METHODS In 2012-2014, whole blood samples were collected from 2,562 children and calcium concentrations were determined by flame atomic absorption spectrometry. The associations of seasons with calcium levels were analyzed by multivariable regression. RESULTS The mean value of calcium concentrations was 1.61 ± 0.13 mmol/l and the overall deficiency was 29.3%. Overall, compared to those in winter, children in spring and summer had significant lower calcium concentrations that decreased by 1.2% (β = -0.012; 95% CI: -0.021, -0.002) and 1.4% (β = -0.014; 95% CI: -0.023, -0.005), respectively; and corresponding higher calcium deficiencies than those in spring, summer, and autumn with odds ratios (OR) were 1.93 (95% CI: 1.39, 2.66), 1.65 (95% CI: 1.21, 2.24), and 1.57 (95% CI: 1.14, 2.15), respectively. Moreover, this seasonality was more significant in girls in whom calcium concentration in summer decreased by 1.9% (β = -0.019; 95% CI: -0.036, -0.003) and OR for calcium deficiencies in summer was 2.46 (1.38-4.41), compared to the girls in winter. CONCLUSIONS The seasons have significant association with blood calcium levels, especially in girls. However, the impact of this seasonality on children's health is still unknown.
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Affiliation(s)
- Meichun Zhang
- Clinical Laboratory Center, Lu'an People's Hospital, The Lu'an Affiliated Hospital of Anhui Medical University, Lu'an, People's Republic of China.
| | - Rongrong Zhai
- Clinical Laboratory Center, Lu'an People's Hospital, The Lu'an Affiliated Hospital of Anhui Medical University, Lu'an, People's Republic of China
| | - Jie Liu
- Clinical Laboratory Center, Lu'an People's Hospital, The Lu'an Affiliated Hospital of Anhui Medical University, Lu'an, People's Republic of China
| | - Hui Guang
- Clinical Laboratory Center, Lu'an People's Hospital, The Lu'an Affiliated Hospital of Anhui Medical University, Lu'an, People's Republic of China
| | - Benzhong Li
- Clinical Laboratory Center, Lu'an People's Hospital, The Lu'an Affiliated Hospital of Anhui Medical University, Lu'an, People's Republic of China
| | - Songtao Zhang
- Clinical Laboratory Center, Lu'an People's Hospital, The Lu'an Affiliated Hospital of Anhui Medical University, Lu'an, People's Republic of China
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32
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Broadbent L, Groves H, Shields MD, Power UF. Respiratory syncytial virus, an ongoing medical dilemma: an expert commentary on respiratory syncytial virus prophylactic and therapeutic pharmaceuticals currently in clinical trials. Influenza Other Respir Viruses 2016; 9:169-78. [PMID: 25847510 PMCID: PMC4474493 DOI: 10.1111/irv.12313] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/25/2015] [Indexed: 12/30/2022] Open
Abstract
As the most important viral cause of severe respiratory disease in infants and increasing recognition as important in the elderly and immunocompromised, respiratory syncytial virus (RSV) is responsible for a massive health burden worldwide. Prophylactic antibodies were successfully developed against RSV. However, their use is restricted to a small group of infants considered at high risk of severe RSV disease. There is still no specific therapeutics or vaccines to combat RSV. As such, it remains a major unmet medical need for most individuals. The World Health Organisations International Clinical Trials Registry Platform (WHO ICTRP) and PubMed were used to identify and review all RSV vaccine, prophylactic and therapeutic candidates currently in clinical trials. This review presents an expert commentary on all RSV-specific prophylactic and therapeutic candidates that have entered clinical trials since 2008.
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Affiliation(s)
- Lindsay Broadbent
- Centre for Infection & Immunity, School of Medicine, Dentistry & Biomedical Sciences, Queen's University Belfast, Belfast, UK
| | - Helen Groves
- Centre for Infection & Immunity, School of Medicine, Dentistry & Biomedical Sciences, Queen's University Belfast, Belfast, UK
| | - Michael D Shields
- Centre for Infection & Immunity, School of Medicine, Dentistry & Biomedical Sciences, Queen's University Belfast, Belfast, UK.,The Royal Belfast Hospital for Sick Children, Belfast, UK
| | - Ultan F Power
- Centre for Infection & Immunity, School of Medicine, Dentistry & Biomedical Sciences, Queen's University Belfast, Belfast, UK
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