1
|
Unwin HJT, Cori A, Imai N, Gaythorpe KAM, Bhatia S, Cattarino L, Donnelly CA, Ferguson NM, Baguelin M. Using next generation matrices to estimate the proportion of infections that are not detected in an outbreak. Epidemics 2022; 41:100637. [PMID: 36219929 DOI: 10.1016/j.epidem.2022.100637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 09/17/2022] [Accepted: 10/03/2022] [Indexed: 12/29/2022] Open
Abstract
Contact tracing, where exposed individuals are followed up to break ongoing transmission chains, is a key pillar of outbreak response for infectious disease outbreaks. Unfortunately, these systems are not fully effective, and infections can still go undetected as people may not remember all their contacts or contacts may not be traced successfully. A large proportion of undetected infections suggests poor contact tracing and surveillance systems, which could be a potential area of improvement for a disease response. In this paper, we present a method for estimating the proportion of infections that are not detected during an outbreak. Our method uses next generation matrices that are parameterized by linked contact tracing data and case line-lists. We validate the method using simulated data from an individual-based model and then investigate two case studies: the proportion of undetected infections in the SARS-CoV-2 outbreak in New Zealand during 2020 and the Ebola epidemic in Guinea during 2014. We estimate that only 5.26% of SARS-CoV-2 infections were not detected in New Zealand during 2020 (95% credible interval: 0.243 - 16.0%) if 80% of contacts were under active surveillance but depending on assumptions about the ratio of contacts not under active surveillance versus contacts under active surveillance 39.0% or 37.7% of Ebola infections were not detected in Guinea (95% credible intervals: 1.69 - 87.0% or 1.70 - 80.9%).
Collapse
Affiliation(s)
- H Juliette T Unwin
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, UK; The Abdul Latif Jameel Institute for Disease and Emergency Analytics (J-IDEA), School of Public Health, Imperial College London, UK.
| | - Anne Cori
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, UK; The Abdul Latif Jameel Institute for Disease and Emergency Analytics (J-IDEA), School of Public Health, Imperial College London, UK
| | - Natsuko Imai
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, UK; The Abdul Latif Jameel Institute for Disease and Emergency Analytics (J-IDEA), School of Public Health, Imperial College London, UK
| | - Katy A M Gaythorpe
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, UK; The Abdul Latif Jameel Institute for Disease and Emergency Analytics (J-IDEA), School of Public Health, Imperial College London, UK
| | - Sangeeta Bhatia
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, UK; The Abdul Latif Jameel Institute for Disease and Emergency Analytics (J-IDEA), School of Public Health, Imperial College London, UK
| | - Lorenzo Cattarino
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, UK; The Abdul Latif Jameel Institute for Disease and Emergency Analytics (J-IDEA), School of Public Health, Imperial College London, UK
| | - Christl A Donnelly
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, UK; The Abdul Latif Jameel Institute for Disease and Emergency Analytics (J-IDEA), School of Public Health, Imperial College London, UK; Department of Statistics, University of Oxford, UK
| | - Neil M Ferguson
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, UK; The Abdul Latif Jameel Institute for Disease and Emergency Analytics (J-IDEA), School of Public Health, Imperial College London, UK
| | - Marc Baguelin
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, UK; The Abdul Latif Jameel Institute for Disease and Emergency Analytics (J-IDEA), School of Public Health, Imperial College London, UK; Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
| |
Collapse
|
2
|
Dembek ZF, Schwartz-Watjen KT, Swiatecka AL, Broadway KM, Hadeed SJ, Mothershead JL, Chekol T, Owens AN, Wu A. Coronavirus Disease 2019 on the Heels of Ebola Virus Disease in West Africa. Pathogens 2021; 10:1266. [PMID: 34684215 PMCID: PMC8537256 DOI: 10.3390/pathogens10101266] [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: 07/31/2021] [Revised: 09/27/2021] [Accepted: 09/29/2021] [Indexed: 01/08/2023] Open
Abstract
This study utilized modeling and simulation to examine the effectiveness of current and potential future COVID-19 response interventions in the West African countries of Guinea, Liberia, and Sierra Leone. A comparison between simulations can highlight which interventions could have an effect on the pandemic in these countries. An extended compartmental model was used to run simulations incorporating multiple vaccination strategies and non-pharmaceutical interventions (NPIs). In addition to the customary categories of susceptible, exposed, infected, and recovered (SEIR) compartments, this COVID-19 model incorporated early and late disease states, isolation, treatment, and death. Lessons learned from the 2014-2016 Ebola virus disease outbreak-especially the optimization of each country's resource allocation-were incorporated in the presented models. For each country, models were calibrated to an estimated number of infections based on actual reported cases and deaths. Simulations were run to test the potential future effects of vaccination and NPIs. Multiple levels of vaccination were considered, based on announced vaccine allocation plans and notional scenarios. Increased vaccination combined with NPI mitigation strategies resulted in thousands of fewer COVID-19 infections in each country. This study demonstrates the importance of increased vaccinations. The levels of vaccination in this study would require substantial increases in vaccination supplies obtained through national purchases or international aid. While this study does not aim to develop a model that predicts the future, it can provide useful information for decision-makers in low- and middle-income nations. Such information can be used to prioritize and optimize limited available resources for targeted interventions that will have the greatest impact on COVID-19 pandemic response.
Collapse
Affiliation(s)
- Zygmunt F. Dembek
- Battelle Memorial Institute, Support to DTRA Technical Reachback, Columbus, OH 43201, USA; (Z.F.D.); (A.L.S.); (S.J.H.); (T.C.)
| | - Kierstyn T. Schwartz-Watjen
- Applied Research Associates (ARA), Support to DTRA Technical Reachback, Albuquerque, NM 87110, USA; (K.T.S.-W.); (J.L.M.)
| | - Anna L. Swiatecka
- Battelle Memorial Institute, Support to DTRA Technical Reachback, Columbus, OH 43201, USA; (Z.F.D.); (A.L.S.); (S.J.H.); (T.C.)
| | - Katherine M. Broadway
- Defense Sciences, Inc. (DSI), Support to DTRA Technical Reachback, San Antonio, TX 78230, USA;
| | - Steven J. Hadeed
- Battelle Memorial Institute, Support to DTRA Technical Reachback, Columbus, OH 43201, USA; (Z.F.D.); (A.L.S.); (S.J.H.); (T.C.)
| | - Jerry L. Mothershead
- Applied Research Associates (ARA), Support to DTRA Technical Reachback, Albuquerque, NM 87110, USA; (K.T.S.-W.); (J.L.M.)
| | - Tesema Chekol
- Battelle Memorial Institute, Support to DTRA Technical Reachback, Columbus, OH 43201, USA; (Z.F.D.); (A.L.S.); (S.J.H.); (T.C.)
| | - Akeisha N. Owens
- Defense Threat Reduction Agency (DTRA), Fort Belvoir, VA 22060, USA;
| | - Aiguo Wu
- Defense Threat Reduction Agency (DTRA), Fort Belvoir, VA 22060, USA;
| |
Collapse
|
3
|
Heterogeneity of contact patterns with Ebola virus disease cases. J Infect 2021; 82:276-316. [DOI: 10.1016/j.jinf.2021.03.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Accepted: 03/15/2021] [Indexed: 11/20/2022]
|
4
|
Carias C, O’Hagan JJ, Gambhir M, Kahn EB, Swerdlow DL, Meltzer MI. Forecasting the 2014 West African Ebola Outbreak. Epidemiol Rev 2019; 41:34-50. [DOI: 10.1093/epirev/mxz013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 04/11/2019] [Accepted: 10/02/2019] [Indexed: 11/13/2022] Open
Abstract
Abstract
In 2014–2015, a large Ebola outbreak afflicted Liberia, Guinea, and Sierra Leone. We performed a systematic review of 26 manuscripts, published between 2014 and April 2015, that forecasted the West African Ebola outbreak while it was occurring, and we derived implications for how results could be interpreted by policymakers. Forecasted case counts varied widely. An important determinant of forecast accuracy for case counts was how far into the future predictions were made. Generally, forecasts for less than 2 months into the future tended to be more accurate than those made for more than 10 weeks into the future. The exceptions were parsimonious statistical models in which the decay of the rate of spread of the pathogen among susceptible individuals was dealt with explicitly. The most important lessons for policymakers regarding future outbreaks, when using similar modeling results, are: 1) uncertainty of forecasts will be greater in the beginning of the outbreak; 2) when data are limited, forecasts produced by models designed to inform specific decisions should be used complementarily for robust decision-making (e.g., 2 statistical models produced the most reliable case-counts forecasts for the studied Ebola outbreak but did not enable understanding of interventions’ impact, whereas several compartmental models could estimate interventions’ impact but required unavailable data); and 3) timely collection of essential data is necessary for optimal model use.
Collapse
|
5
|
Dhillon RS, Srikrishna D. When is contact tracing not enough to stop an outbreak? THE LANCET. INFECTIOUS DISEASES 2019; 18:1302-1304. [PMID: 30507446 DOI: 10.1016/s1473-3099(18)30656-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 10/18/2018] [Indexed: 11/17/2022]
Affiliation(s)
- Ranu S Dhillon
- Division of Global Health Equity, Brigham and Women's Hospital, Boston MA 02115, USA.
| | | |
Collapse
|
6
|
Campbell F, Cori A, Ferguson N, Jombart T. Bayesian inference of transmission chains using timing of symptoms, pathogen genomes and contact data. PLoS Comput Biol 2019; 15:e1006930. [PMID: 30925168 PMCID: PMC6457559 DOI: 10.1371/journal.pcbi.1006930] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 04/10/2019] [Accepted: 03/04/2019] [Indexed: 12/13/2022] Open
Abstract
There exists significant interest in developing statistical and computational tools for inferring 'who infected whom' in an infectious disease outbreak from densely sampled case data, with most recent studies focusing on the analysis of whole genome sequence data. However, genomic data can be poorly informative of transmission events if mutations accumulate too slowly to resolve individual transmission pairs or if there exist multiple pathogens lineages within-host, and there has been little focus on incorporating other types of outbreak data. We present here a methodology that uses contact data for the inference of transmission trees in a statistically rigorous manner, alongside genomic data and temporal data. Contact data is frequently collected in outbreaks of pathogens spread by close contact, including Ebola virus (EBOV), severe acute respiratory syndrome coronavirus (SARS-CoV) and Mycobacterium tuberculosis (TB), and routinely used to reconstruct transmission chains. As an improvement over previous, ad-hoc approaches, we developed a probabilistic model that relates a set of contact data to an underlying transmission tree and integrated this in the outbreaker2 inference framework. By analyzing simulated outbreaks under various contact tracing scenarios, we demonstrate that contact data significantly improves our ability to reconstruct transmission trees, even under realistic limitations on the coverage of the contact tracing effort and the amount of non-infectious mixing between cases. Indeed, contact data is equally or more informative than fully sampled whole genome sequence data in certain scenarios. We then use our method to analyze the early stages of the 2003 SARS outbreak in Singapore and describe the range of transmission scenarios consistent with contact data and genetic sequence in a probabilistic manner for the first time. This simple yet flexible model can easily be incorporated into existing tools for outbreak reconstruction and should permit a better integration of genomic and epidemiological data for inferring transmission chains.
Collapse
Affiliation(s)
- Finlay Campbell
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, United Kingdom
| | - Anne Cori
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, United Kingdom
| | - Neil Ferguson
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, United Kingdom
| | - Thibaut Jombart
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, United Kingdom
- Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, United Kingdom
- UK Public Health Rapid Support Team, London, United Kingdom
| |
Collapse
|
7
|
Cavany SM, Vynnycky E, Anderson CS, Maguire H, Sandmann F, Thomas HL, White RG, Sumner T. Should NICE reconsider the 2016 UK guidelines on TB contact tracing? A cost-effectiveness analysis of contact investigations in London. Thorax 2018; 74:185-193. [PMID: 30121574 DOI: 10.1136/thoraxjnl-2018-211662] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 07/08/2018] [Accepted: 07/30/2018] [Indexed: 11/04/2022]
Abstract
BACKGROUND In January 2016, clinical TB guidance in the UK changed to no longer recommend screening contacts of non-pulmonary, non-laryngeal (ETB) index cases. However, no new evidence was cited for this change, and there is evidence that screening these contacts may be worthwhile. The objective of this study was to estimate the cost-effectiveness of screening contacts of adult ETB cases and adult pulmonary or laryngeal TB (PTB) cases in London, UK. METHODS We carried out a cross-sectional analysis of data collected on TB index cases and contacts in the London TB register and an economic evaluation using a static model describing contact tracing outcomes. Incremental cost-effectiveness ratios (ICERs) were calculated using no screening as the baseline comparator. All adult TB cases (≥15 years old) in London from 2012 to 2015, and their contacts, were eligible (2465/5084 PTB and 2559/6090 ETB index cases were included). RESULTS Assuming each contact with PTB infects one person/month, the ICER of screening contacts of ETB cases was £78 000/quality-adjusted life-years (QALY) (95% CI 39 000 to 140 000), and screening contacts of PTB cases was £30 000/QALY (95% CI 18 000 to 50 000). The ICER of screening contacts of ETB cases was £30 000/QALY if each contact with PTB infects 3.4 people/month. Limitations of this study include the use of self-reported symptomatic periods and lack of knowledge about onward transmission from PTB contacts. CONCLUSIONS Screening contacts of ETB cases in London was almost certainly not cost-effective at any conventional willingness-to-pay threshold in England, supporting recent changes to National Institute for Health and Care Excellence national guidelines.
Collapse
Affiliation(s)
- Sean M Cavany
- TB Modelling Group, TB Centre and CMMID, Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, London, UK.,Statistics, Modelling and Economics Department, Public Health England, London, UK.,Department of Biological Sciences, University of Notre Dame, South Bend, IN, United States
| | - Emilia Vynnycky
- TB Modelling Group, TB Centre and CMMID, Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, London, UK.,Statistics, Modelling and Economics Department, Public Health England, London, UK
| | | | - Helen Maguire
- Field Epidemiology Service, Public Health England, London, UK.,Institute for Global Health, University College London, London, UK
| | - Frank Sandmann
- Statistics, Modelling and Economics Department, Public Health England, London, UK.,CMMID, Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, London, UK
| | - H Lucy Thomas
- Respiratory Diseases Department, Public Health England, London, UK
| | - Richard G White
- TB Modelling Group, TB Centre and CMMID, Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, London, UK
| | - Tom Sumner
- TB Modelling Group, TB Centre and CMMID, Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, London, UK
| |
Collapse
|
8
|
Contact tracing with a real-time location system: A case study of increasing relative effectiveness in an emergency department. Am J Infect Control 2017; 45:1308-1311. [PMID: 28967513 PMCID: PMC7115342 DOI: 10.1016/j.ajic.2017.08.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 08/13/2017] [Accepted: 08/14/2017] [Indexed: 11/27/2022]
Abstract
Contact tracing is an essential step in infectious disease control and prevention. Using Electronic medical record (EMR) is challenging and misses a number of potential exposures. Real time location system (RTLS) doubled the potential exposures list for pertussis disease beyond the conventional method of EMR-based contact identification RTLS is more efficient and timely in the process of contact tracing. Further studies with larger sample size are needed to confirm the findings.
Background Contact tracing is the systematic method of identifying individuals potentially exposed to infectious diseases. Electronic medical record (EMR) use for contact tracing is time-consuming and may miss exposed individuals. Real-time location systems (RTLSs) may improve contact identification. Therefore, the relative effectiveness of these 2 contact tracing methodologies were evaluated. Methods During a pertussis outbreak in the United States, a retrospective case study was conducted between June 14 and August 31, 2016, to identify the contacts of confirmed pertussis cases, using EMR and RTLS data in the emergency department of a tertiary care medical center. Descriptive statistics and a paired t test (α = 0.05) were performed to compare contacts identified by EMR versus RTLS, as was correlation between pertussis patient length of stay and the number of potential contacts. Results Nine cases of pertussis presented to the emergency department during the identified time period. RTLS doubled the potential exposure list (P < .01). Length of stay had significant positive correlation with contacts identified by RTLS (ρ = 0.79; P = .01) but not with EMR (ρ = 0.43; P = .25). Conclusions RTLS doubled the potential pertussis exposures beyond EMR-based contact identification. Thus, RTLS may be a valuable addition to the practice of contact tracing and infectious disease monitoring.
Collapse
|
9
|
Schafer IJ, Knudsen E, McNamara LA, Agnihotri S, Rollin PE, Islam A. The Epi Info Viral Hemorrhagic Fever (VHF) Application: A Resource for Outbreak Data Management and Contact Tracing in the 2014-2016 West Africa Ebola Epidemic. J Infect Dis 2016; 214:S122-S136. [PMID: 27587635 DOI: 10.1093/infdis/jiw272] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The Epi Info Viral Hemorrhagic Fever application (Epi Info VHF) was developed in response to challenges managing outbreak data during four 2012 filovirus outbreaks. Development goals included combining case and contact data in a relational database, facilitating data-driven contact tracing, and improving outbreak data consistency and use. The application was first deployed in Guinea, when the West Africa Ebola epidemic was detected, in March 2014, and has been used in 7 African countries and 2 US states. Epi Info VHF enabled reporting of compatible data from multiple countries, contributing to international Ebola knowledge. However, challenges were encountered in accommodating the epidemic's unexpectedly large magnitude, addressing country-specific needs within 1 software product, and using the application in settings with limited Internet access and information technology support. Use of Epi Info VHF in the West Africa Ebola epidemic highlighted the fundamental importance of good data management for effective outbreak response, regardless of the software used.
Collapse
Affiliation(s)
- Ilana J Schafer
- Epi Info Team, Division of Health Informatics and Surveillance Viral Special Pathogens Branch, Division of High Consequence Pathogens and Pathology
| | - Erik Knudsen
- Epi Info Team, Division of Health Informatics and Surveillance
| | - Lucy A McNamara
- Meningitis and Vaccine Preventable Diseases Branch, Division of Bacterial Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia
| | | | - Pierre E Rollin
- Viral Special Pathogens Branch, Division of High Consequence Pathogens and Pathology
| | - Asad Islam
- Epi Info Team, Division of Health Informatics and Surveillance
| |
Collapse
|
10
|
McNamara LA, Schafer IJ, Nolen LD, Gorina Y, Redd JT, Lo T, Ervin E, Henao O, Dahl BA, Morgan O, Hersey S, Knust B. Ebola Surveillance - Guinea, Liberia, and Sierra Leone. MMWR Suppl 2016; 65:35-43. [PMID: 27389614 DOI: 10.15585/mmwr.su6503a6] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
Abstract
Developing a surveillance system during a public health emergency is always challenging but is especially so in countries with limited public health infrastructure. Surveillance for Ebola virus disease (Ebola) in the West African countries heavily affected by Ebola (Guinea, Liberia, and Sierra Leone) faced numerous impediments, including insufficient numbers of trained staff, community reticence to report cases and contacts, limited information technology resources, limited telephone and Internet service, and overwhelming numbers of infected persons. Through the work of CDC and numerous partners, including the countries' ministries of health, the World Health Organization, and other government and nongovernment organizations, functional Ebola surveillance was established and maintained in these countries. CDC staff were heavily involved in implementing case-based surveillance systems, sustaining case surveillance and contact tracing, and interpreting surveillance data. In addition to helping the ministries of health and other partners understand and manage the epidemic, CDC's activities strengthened epidemiologic and data management capacity to improve routine surveillance in the countries affected, even after the Ebola epidemic ended, and enhanced local capacity to respond quickly to future public health emergencies. However, the many obstacles overcome during development of these Ebola surveillance systems highlight the need to have strong public health, surveillance, and information technology infrastructure in place before a public health emergency occurs. Intense, long-term focus on strengthening public health surveillance systems in developing countries, as described in the Global Health Security Agenda, is needed.The activities summarized in this report would not have been possible without collaboration with many U.S and international partners (http://www.cdc.gov/vhf/ebola/outbreaks/2014-west-africa/partners.html).
Collapse
Affiliation(s)
- Lucy A McNamara
- Division of Bacterial Diseases, National Center for Immunization and Respiratory Diseases, CDC
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|