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Keita M, Cherif IS, Polonsky JA, Boland ST, Kandako Y, Cherif MS, Kourouma M, Kamano AA, Bah H, Fofana IS, Ki-Zerbo GA, Dagron S, Chamla D, Gueye AS, Keiser O. Factors Associated with Reliable Contact Tracing During the 2021 Ebola Virus Disease Outbreak in Guinea. J Epidemiol Glob Health 2024:10.1007/s44197-024-00202-y. [PMID: 38372893 DOI: 10.1007/s44197-024-00202-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2023] [Accepted: 01/30/2024] [Indexed: 02/20/2024] Open
Abstract
BACKGROUND In 2021, an Ebola virus disease (EVD) outbreak was declared in Guinea, linked to persistent virus from the 2014-2016 West Africa Epidemic. This paper analyzes factors associated with contact tracing reliability (defined as completion of a 21-day daily follow-up) during the 2021 outbreak, and transitively, provides recommendations for enhancing contact tracing reliability in future. METHODS We conducted a descriptive and analytical cross-sectional study using multivariate regression analysis of contact tracing data from 1071 EVD contacts of 23 EVD cases (16 confirmed and 7 probable). RESULTS Findings revealed statistically significant factors affecting contact tracing reliability. Unmarried contacts were 12.76× more likely to miss follow-up than those married (OR = 12.76; 95% CI [3.39-48.05]; p < 0.001). Rural-dwelling contacts had 99% lower odds of being missed during the 21-day follow-up, compared to those living in urban areas (OR = 0.01; 95% CI [0.00-0.02]; p < 0.01). Contacts who did not receive food donations were 3× more likely to be missed (OR = 3.09; 95% CI [1.68-5.65]; p < 0.001) compared to those who received them. Contacts in health areas with a single team were 8× more likely to be missed (OR = 8.16; 95% CI [5.57-11.96]; p < 0.01) than those in health areas with two or more teams (OR = 1.00; 95% CI [1.68-5.65]; p < 0.001). Unvaccinated contacts were 30.1× more likely to be missed compared to vaccinated contacts (OR = 30.1; 95% CI [5.12-176.83]; p < 0.001). CONCLUSION Findings suggest that contact tracing reliability can be significantly influenced by various demographic and organizational factors. Considering and understanding these factors-and where possible addressing them-may be crucial when designing and implementing contact tracing strategies during future outbreaks in low-resource settings.
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Affiliation(s)
- Mory Keita
- World Health Organization, Regional Office for Africa, Brazzaville, Congo.
- Institute of Global Health, Faculty of Medicine, University of Geneva, Geneva, Switzerland.
| | | | - Jonathan A Polonsky
- Geneva Centre of Humanitarian Studies, Faculty of Medicine, University of Geneva, Geneva, Switzerland
- Epicentre, Geneva, Switzerland
| | - Samuel T Boland
- World Health Organization, Regional Office for Africa, Brazzaville, Congo
- Chatham House, London, UK
| | - Youba Kandako
- Country Office for Guinea, World Health Organization, Conakry, Guinea
| | | | - Mamadou Kourouma
- Country Office for Guinea, World Health Organization, Conakry, Guinea
| | | | - Houssainatou Bah
- Country Office for Guinea, World Health Organization, Conakry, Guinea
| | | | | | - Stephanie Dagron
- Institute of Global Health, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Dick Chamla
- World Health Organization, Regional Office for Africa, Brazzaville, Congo
| | - Abdou Salam Gueye
- World Health Organization, Regional Office for Africa, Brazzaville, Congo
| | - Olivia Keiser
- Institute of Global Health, Faculty of Medicine, University of Geneva, Geneva, Switzerland
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Keita M, Polonsky JA, Ahuka-Mundeke S, Ilumbulumbu MK, Dakissaga A, Boiro H, Anoko JN, Diassy L, Ngwama JK, Bah H, Tosalisana MK, Kitenge Omasumbu R, Chérif IS, Boland ST, Delamou A, Yam A, Flahault A, Dagron S, Gueye AS, Keiser O, Fall IS. A community-based contact isolation strategy to reduce the spread of Ebola virus disease: an analysis of the 2018-2020 outbreak in the Democratic Republic of the Congo. BMJ Glob Health 2023; 8:e011907. [PMID: 37263672 PMCID: PMC10254818 DOI: 10.1136/bmjgh-2023-011907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 05/06/2023] [Indexed: 06/03/2023] Open
Abstract
INTRODUCTION Despite tremendous progress in the development of diagnostics, vaccines and therapeutics for Ebola virus disease (EVD), challenges remain in the implementation of holistic strategies to rapidly curtail outbreaks. We investigated the effectiveness of a community-based contact isolation strategy to limit the spread of the disease in the Democratic Republic of Congo (DRC). METHODS We did a quasi-experimental comparison study. Eligible participants were EVD contacts registered from 12 June 2019 to 18 May 2020 in Beni and Mabalako Health Zones. Intervention group participants were isolated to specific community sites for the duration of their follow-up. Comparison group participants underwent contact tracing without isolation. The primary outcome was measured as the reproduction number (R) in the two groups. Secondary outcomes were the delay from symptom onset to isolation and case management, case fatality rate (CFR) and vaccination uptake. RESULTS 27 324 EVD contacts were included in the study; 585 in the intervention group and 26 739 in the comparison group. The intervention group generated 32 confirmed cases (5.5%) in the first generation, while the comparison group generated 87 (0.3%). However, the 32 confirmed cases arising from the intervention contacts did not generate any additional transmission (R=0.00), whereas the 87 confirmed cases arising from the comparison group generated 99 secondary cases (R=1.14). The average delay between symptom onset and case isolation was shorter (1.3 vs 4.8 days; p<0.0001), CFR lower (12.5% vs 48.4%; p=0.0001) and postexposure vaccination uptake higher (86.0% vs 56.8%; p<0.0001) in the intervention group compared with the comparison group. A significant difference was also found between intervention and comparison groups in survival rate at the discharge of hospitalised confirmed patients (87.9% vs 47.7%, respectively; p=0.0004). CONCLUSION The community-based contact isolation strategy used in DRC shows promise as a potentially effective approach for the rapid cessation of EVD transmission, highlighting the importance of rapidly implemented, community-oriented and trust-building control strategies.
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Affiliation(s)
- Mory Keita
- Emergency Preparedness and Response, World Health Organization Regional Office for Africa, Brazzaville, Congo
- Institute of Global Health, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Jonathan A Polonsky
- Geneva Centre of Humanitarian Studies, University of Geneva, Geneva, Switzerland
| | - Steve Ahuka-Mundeke
- Département de Virologie, Institut National de Recherche Biomédicale, Kinshasa, Congo (the Democratic Republic of the)
| | | | - Adama Dakissaga
- Direction Régionale de la Santé du Plateau Central, Ministère de la Santé et de l'Hygiène Publique, Ziniaré, Burkina Faso
| | - Hamadou Boiro
- Emergency Preparedness and Response, World Health Organization Regional Office for Africa, Brazzaville, Congo
| | - Julienne Ngoundoung Anoko
- Emergency Preparedness and Response, World Health Organization Regional Office for Africa, Brazzaville, Congo
| | - Lamine Diassy
- Emergency Preparedness and Response, World Health Organization Regional Office for Africa, Brazzaville, Congo
| | - John Kombe Ngwama
- Direction Générale de la Lutte contre la Maladie, Ministère de la Santé, Kinshasa, Democratic Republic of Congo
| | - Houssainatou Bah
- Emergency Preparedness and Response, World Health Organization Regional Office for Africa, Brazzaville, Congo
| | | | - Richard Kitenge Omasumbu
- Equipe Médicale d'Urgence, Ministère de la Santé Publique, Kinshasa, Congo (the Democratic Republic of the)
| | | | | | - Alexandre Delamou
- African Centre of Excellence for the Prevention and Control of Communicable Diseases, Gamal Abdel Nasser University of Conakry, Conakry, Guinea
| | - Abdoulaye Yam
- Emergency Preparedness and Response, World Health Organization Regional Office for Africa, Brazzaville, Congo
| | - Antoine Flahault
- Institute of Global Health, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Stéphanie Dagron
- Institute of Global Health, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Abdou Salam Gueye
- Emergency Preparedness and Response, World Health Organization Regional Office for Africa, Brazzaville, Congo
| | - Olivia Keiser
- Institute of Global Health, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Ibrahima Socé Fall
- Global Neglected Tropical Diseases programme, World Health Organization, Geneva, Switzerland
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Keita M, Talisuna A, Chamla D, Burmen B, Cherif MS, Polonsky JA, Boland S, Barry B, Mesfin S, Traoré FA, Traoré J, Kimenyi JP, Diallo AB, Godjedo TP, Traore T, Delamou A, Ki-Zerbo GA, Dagron S, Keiser O, Gueye AS. Investing in preparedness for rapid detection and control of epidemics: analysis of health system reforms and their effect on 2021 Ebola virus disease epidemic response in Guinea. BMJ Glob Health 2023; 8:bmjgh-2022-010984. [PMID: 36599498 DOI: 10.1136/bmjgh-2022-010984] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Accepted: 12/21/2022] [Indexed: 01/05/2023] Open
Abstract
The 2014-2016 West Africa Ebola Virus Disease (EVD) Epidemic devastated Guinea's health system and constituted a public health emergency of international concern. Following the crisis, Guinea invested in the establishment of basic health system reforms and crucial legal instruments for strengthening national health security in line with the WHO's recommendations for ensuring better preparedness for (and, therefore, a response to) health emergencies. The investments included the scaling up of Integrated Disease Surveillance and Response; Joint External Evaluation of International Health Regulation capacities; National Action Plan for Health Security; Simulation Exercises; One Health platforms; creation of decentralised structures such as regional and prefectural Emergency Operation Centres; Risk assessment and hazard identification; Expanding human resources capacity; Early Warning Alert System and community preparedness. These investments were tested in the subsequent 2021 EVD outbreak and other epidemics. In this case, there was a timely declaration and response to the 2021 EVD epidemic, a lower-case burden and mortality rate, a shorter duration of the epidemic and a significant reduction in the cost of the response. Similarly, there was timely detection, response and containment of other epidemics including Lassa fever and Marburg virus disease. Findings suggest the utility of the preparedness activities for the early detection and efficient containment of outbreaks, which, therefore, underlines the need for all countries at risk of infectious disease epidemics to invest in similar reforms. Doing so promises to be not only cost-effective but also lifesaving.
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Affiliation(s)
- Mory Keita
- Emergency Preparedness and Response, World Health Organization Regional Office for Africa, Brazzaville, Republic of Congo .,Institute of Global Health, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Ambrose Talisuna
- Emergency Preparedness and Response, World Health Organization Regional Office for Africa, Brazzaville, Republic of Congo
| | - Dick Chamla
- Emergency Preparedness and Response, World Health Organization Regional Office for Africa, Brazzaville, Republic of Congo
| | - Barbara Burmen
- Health Security Preparedness, World Health Organization, Geneva, Switzerland
| | - Mahamoud Sama Cherif
- Faculty of Sciences and Health Technics, Gamal Abdel Nasser University of Conakry, Conakry, Guinea
| | - Jonathan A Polonsky
- Geneva Centre of Humanitarian Studies, Faculty of Medicine, University of Geneva, Geneva, Switzerland.,Emergency Response, World Health Organization, Geneva, Switzerland
| | - Samuel Boland
- Department of Global Health and Development, London School of Hygiene and Tropical Medicine, London, UK
| | - Boubacar Barry
- Emergency Response, World Health Organization, Geneva, Switzerland
| | - Samuel Mesfin
- Emergency Response, World Health Organization, Geneva, Switzerland
| | - Fodé Amara Traoré
- National Agency for Health Security, Ministry of Health, Conakry, Guinea
| | - Jean Traoré
- National Agency for Health Security, Ministry of Health, Conakry, Guinea
| | - Jean Paul Kimenyi
- Emergency Preparedness and Response, World Health Organization Regional Office for Africa, Brazzaville, Republic of Congo
| | - Amadou Bailo Diallo
- Emergency Preparedness and Response, World Health Organization Regional Office for Africa, Brazzaville, Republic of Congo
| | - Togbemabou Primous Godjedo
- Emergency Preparedness and Response, World Health Organization Regional Office for Africa, Brazzaville, Republic of Congo
| | - Tieble Traore
- Emergency Preparedness and Response, World Health Organization Regional Office for Africa, Brazzaville, Republic of Congo
| | - Alexandre Delamou
- African Centre of Excellence for the Prevention and Control of Communicable Diseases, Gamal Abdel Nasser University of Conakry, Conakry, Guinea
| | - Georges Alfred Ki-Zerbo
- Office at the African Union (AU) and Un Economic Commission for Africa (UNECA), World Health Organization Regional Office for Africa, Brazzaville, Republic of Congo
| | - Stephanie Dagron
- Institute of Global Health, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Olivia Keiser
- Institute of Global Health, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Abdou Salam Gueye
- Emergency Preparedness and Response, World Health Organization Regional Office for Africa, Brazzaville, Republic of Congo
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Lerdsuwansri R, Sangnawakij P, Böhning D, Sansilapin C, Chaifoo W, Polonsky JA, Del Rio Vilas VJ. Sensitivity of contact-tracing for COVID-19 in Thailand: a capture-recapture application. BMC Infect Dis 2022; 22:101. [PMID: 35093019 PMCID: PMC8799986 DOI: 10.1186/s12879-022-07046-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Accepted: 01/11/2022] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND We investigate the completeness of contact tracing for COVID-19 during the first wave of the COVID-19 pandemic in Thailand, from early January 2020 to 30 June 2020. METHODS Uni-list capture-recapture models were applied to the frequency distributions of index cases to inform two questions: (1) the unobserved number of index cases with contacts, and (2) the unobserved number of index cases with secondary cases among their contacts. RESULTS Generalized linear models (using Poisson and logistic families) did not return any significant predictor (age, sex, nationality, number of contacts per case) on the risk of transmission and hence capture-recapture models did not adjust for observed heterogeneity. Best fitting models, a zero truncated negative binomial for question 1 and zero-truncated Poisson for question 2, returned sensitivity estimates for contact tracing performance of 77.6% (95% CI = 73.75-81.54%) and 67.6% (95% CI = 53.84-81.38%), respectively. A zero-inflated negative binomial model on the distribution of index cases with secondary cases allowed the estimation of the effective reproduction number at 0.14 (95% CI = 0.09-0.22), and the overdispersion parameter at 0.1. CONCLUSION Completeness of COVID-19 contact tracing in Thailand during the first wave appeared moderate, with around 67% of infectious transmission chains detected. Overdispersion was present suggesting that most of the index cases did not result in infectious transmission chains and the majority of transmission events stemmed from a small proportion of index cases.
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Affiliation(s)
- R Lerdsuwansri
- Department of Mathematics and Statistics, Faculty of Science and Technology, Thammasat University, Pathum Thani, Thailand.
| | - P Sangnawakij
- Department of Mathematics and Statistics, Faculty of Science and Technology, Thammasat University, Pathum Thani, Thailand
| | - D Böhning
- Southampton Statistical Sciences Research Institute and Mathematical Sciences, University of Southampton, Southampton, UK
| | - C Sansilapin
- Department of Disease Control, Ministry of Public Health, Nonthaburi, Thailand
| | - W Chaifoo
- Department of Disease Control, Ministry of Public Health, Nonthaburi, Thailand
| | | | - Victor J Del Rio Vilas
- World Health Organization, World Health Emergencies, South East Asia Regional Office, New Delhi, India
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Polonsky JA, Bhatia S, Fraser K, Hamlet A, Skarp J, Stopard IJ, Hugonnet S, Kaiser L, Lengeler C, Blanchet K, Spiegel P. Feasibility, acceptability, and effectiveness of non-pharmaceutical interventions against infectious diseases among crisis-affected populations: a scoping review. Infect Dis Poverty 2022; 11:14. [PMID: 35090570 PMCID: PMC8796190 DOI: 10.1186/s40249-022-00935-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 01/03/2022] [Indexed: 12/23/2022] Open
Abstract
Background Non-pharmaceutical interventions (NPIs) are a crucial suite of measures to prevent and control infectious disease outbreaks. Despite being particularly important for crisis-affected populations and those living in informal settlements, who typically reside in overcrowded and resource limited settings with inadequate access to healthcare, guidance on NPI implementation rarely takes the specific needs of such populations into account. We therefore conducted a systematic scoping review of the published evidence to describe the landscape of research and identify evidence gaps concerning the acceptability, feasibility, and effectiveness of NPIs among crisis-affected populations and informal settlements. Methods We systematically reviewed peer-reviewed articles published between 1970 and 2020 to collate available evidence on the feasibility, acceptability, and effectiveness of NPIs in crisis-affected populations and informal settlements. We performed quality assessments of each study using a standardised questionnaire. We analysed the data to produce descriptive summaries according to a number of categories: date of publication; geographical region of intervention; typology of crisis, shelter, modes of transmission, NPI, research design; study design; and study quality. Results Our review included 158 studies published in 85 peer-reviewed articles. Most research used low quality study designs. The acceptability, feasibility, and effectiveness of NPIs was highly context dependent. In general, simple and cost-effective interventions such as community-level environmental cleaning and provision of water, sanitation and hygiene services, and distribution of items for personal protection such as insecticide-treated nets, were both highly feasible and acceptable. Logistical, financial, and human resource constraints affected both the implementation and sustainability of measures. Community engagement emerged as a strong factor contributing to the effectiveness of NPIs. Conversely, measures that involve potential restriction on personal liberty such as case isolation and patient care and burial restrictions were found to be less acceptable, despite apparent effectiveness. Conclusions Overall, the evidence base was variable, with substantial knowledge gaps which varied between settings and pathogens. Based on the current landscape, robust evidence-based guidance is not possible, and a research agenda is urgently required that focusses on these specific vulnerable populations. Although implementation of NPIs presents unique practical challenges in these settings, it is critical that such an agenda is put in place, and that the lessons learned from historical and present experiences are documented to build a firm evidence base. Graphical Abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s40249-022-00935-7.
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Polonsky JA, Böhning D, Keita M, Ahuka-Mundeke S, Nsio-Mbeta J, Abedi AA, Mossoko M, Estill J, Keiser O, Kaiser L, Yoti Z, Sangnawakij P, Lerdsuwansri R, Vilas VJDR. Novel Use of Capture-Recapture Methods to Estimate Completeness of Contact Tracing during an Ebola Outbreak, Democratic Republic of the Congo, 2018-2020. Emerg Infect Dis 2021; 27:3063-3072. [PMID: 34808076 PMCID: PMC8632194 DOI: 10.3201/eid2712.204958] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Despite its critical role in containing outbreaks, the efficacy of contact tracing, measured as the sensitivity of case detection, remains an elusive metric. We estimated the sensitivity of contact tracing by applying unilist capture-recapture methods on data from the 2018–2020 outbreak of Ebola virus disease in the Democratic Republic of the Congo. To compute sensitivity, we applied different distributional assumptions to the zero-truncated count data to estimate the number of unobserved case-patients with any contacts and infected contacts. Geometric distributions were the best-fitting models. Our results indicate that contact tracing efforts identified almost all (n = 792, 99%) of case-patients with any contacts but only half (n = 207, 48%) of case-patients with infected contacts, suggesting that contact tracing efforts performed well at identifying contacts during the listing stage but performed poorly during the contact follow-up stage. We discuss extensions to our work and potential applications for the ongoing coronavirus pandemic.
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Polonsky JA, Ivey M, Mazhar MKA, Rahman Z, le Polain de Waroux O, Karo B, Jalava K, Vong S, Baidjoe A, Diaz J, Finger F, Habib ZH, Halder CE, Haskew C, Kaiser L, Khan AS, Sangal L, Shirin T, Zaki QA, Salam MA, White K. Epidemiological, clinical, and public health response characteristics of a large outbreak of diphtheria among the Rohingya population in Cox's Bazar, Bangladesh, 2017 to 2019: A retrospective study. PLoS Med 2021; 18:e1003587. [PMID: 33793554 PMCID: PMC8059831 DOI: 10.1371/journal.pmed.1003587] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 04/21/2021] [Accepted: 03/15/2021] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Unrest in Myanmar in August 2017 resulted in the movement of over 700,000 Rohingya refugees to overcrowded camps in Cox's Bazar, Bangladesh. A large outbreak of diphtheria subsequently began in this population. METHODS AND FINDINGS Data were collected during mass vaccination campaigns (MVCs), contact tracing activities, and from 9 Diphtheria Treatment Centers (DTCs) operated by national and international organizations. These data were used to describe the epidemiological and clinical features and the control measures to prevent transmission, during the first 2 years of the outbreak. Between November 10, 2017 and November 9, 2019, 7,064 cases were reported: 285 (4.0%) laboratory-confirmed, 3,610 (51.1%) probable, and 3,169 (44.9%) suspected cases. The crude attack rate was 51.5 cases per 10,000 person-years, and epidemic doubling time was 4.4 days (95% confidence interval [CI] 4.2-4.7) during the exponential growth phase. The median age was 10 years (range 0-85), and 3,126 (44.3%) were male. The typical symptoms were sore throat (93.5%), fever (86.0%), pseudomembrane (34.7%), and gross cervical lymphadenopathy (GCL; 30.6%). Diphtheria antitoxin (DAT) was administered to 1,062 (89.0%) out of 1,193 eligible patients, with adverse reactions following among 229 (21.6%). There were 45 deaths (case fatality ratio [CFR] 0.6%). Household contacts for 5,702 (80.7%) of 7,064 cases were successfully traced. A total of 41,452 contacts were identified, of whom 40,364 (97.4%) consented to begin chemoprophylaxis; adherence was 55.0% (N = 22,218) at 3-day follow-up. Unvaccinated household contacts were vaccinated with 3 doses (with 4-week interval), while a booster dose was administered if the primary vaccination schedule had been completed. The proportion of contacts vaccinated was 64.7% overall. Three MVC rounds were conducted, with administrative coverage varying between 88.5% and 110.4%. Pentavalent vaccine was administered to those aged 6 weeks to 6 years, while tetanus and diphtheria (Td) vaccine was administered to those aged 7 years and older. Lack of adequate diagnostic capacity to confirm cases was the main limitation, with a majority of cases unconfirmed and the proportion of true diphtheria cases unknown. CONCLUSIONS To our knowledge, this is the largest reported diphtheria outbreak in refugee settings. We observed that high population density, poor living conditions, and fast growth rate were associated with explosive expansion of the outbreak during the initial exponential growth phase. Three rounds of mass vaccinations targeting those aged 6 weeks to 14 years were associated with only modestly reduced transmission, and additional public health measures were necessary to end the outbreak. This outbreak has a long-lasting tail, with Rt oscillating at around 1 for an extended period. An adequate global DAT stockpile needs to be maintained. All populations must have access to health services and routine vaccination, and this access must be maintained during humanitarian crises.
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Affiliation(s)
- Jonathan A. Polonsky
- World Health Organization, Geneva, Switzerland
- Institute of Global Health, Faculty of Medicine, University of Geneva, Geneva, Switzerland
- * E-mail:
| | - Melissa Ivey
- Médecins Sans Frontières, Amsterdam, the Netherlands
| | | | - Ziaur Rahman
- Ministry of Health and Family Welfare, Dhaka, Bangladesh
| | - Olivier le Polain de Waroux
- World Health Organization, Geneva, Switzerland
- Global Outbreak Alert and Response Network (GOARN), Geneva, Switzerland
- Public Health England, London, United Kingdom
- London School of Hygiene and Tropical Medicine, London, United Kingdom
- UK-Public Health Rapid Support Team, London, United Kingdom
| | - Basel Karo
- Global Outbreak Alert and Response Network (GOARN), Geneva, Switzerland
- Information Centre for International Health Protection (ZIG 1), Robert Koch Institute (RKI), Berlin, Germany
| | - Katri Jalava
- World Health Organization Country Office for Bangladesh, Dhaka, Bangladesh
| | - Sirenda Vong
- World Health Organization South-East Asia Regional Office, New Delhi, India
| | - Amrish Baidjoe
- London School of Hygiene and Tropical Medicine, London, United Kingdom
- World Health Organization South-East Asia Regional Office, New Delhi, India
| | - Janet Diaz
- World Health Organization, Geneva, Switzerland
| | - Flavio Finger
- Global Outbreak Alert and Response Network (GOARN), Geneva, Switzerland
- London School of Hygiene and Tropical Medicine, London, United Kingdom
- Epicentre, Paris, France
| | - Zakir H. Habib
- Institute of Epidemiology Disease Control and Research (IEDCR), Dhaka, Bangladesh
| | | | | | - Laurent Kaiser
- Institute of Global Health, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Ali S. Khan
- Global Outbreak Alert and Response Network (GOARN), Geneva, Switzerland
- College of Public Health, University of Nebraska Medical Center, Nebraska, United States of America
| | - Lucky Sangal
- World Health Organization Country Office for India, New Delhi, India
| | - Tahmina Shirin
- Institute of Epidemiology Disease Control and Research (IEDCR), Dhaka, Bangladesh
| | - Quazi Ahmed Zaki
- Institute of Epidemiology Disease Control and Research (IEDCR), Dhaka, Bangladesh
| | | | - Kate White
- Médecins Sans Frontières, Amsterdam, the Netherlands
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Ratnayake R, Tammaro M, Tiffany A, Kongelf A, Polonsky JA, McClelland A. People-centred surveillance: a narrative review of community-based surveillance among crisis-affected populations. Lancet Planet Health 2020; 4:e483-e495. [PMID: 33038321 PMCID: PMC7542093 DOI: 10.1016/s2542-5196(20)30221-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 08/19/2020] [Accepted: 08/24/2020] [Indexed: 06/11/2023]
Abstract
Outbreaks of disease in settings affected by crises grow rapidly due to late detection and weakened public health systems. Where surveillance is underfunctioning, community-based surveillance can contribute to rapid outbreak detection and response, a core capacity of the International Health Regulations. We reviewed articles describing the potential for community-based surveillance to detect diseases of epidemic potential, outbreaks, and mortality among populations affected by crises. Surveillance objectives have included the early warning of outbreaks, active case finding during outbreaks, case finding for eradication programmes, and mortality surveillance. Community-based surveillance can provide sensitive and timely detection, identify valid signals for diseases with salient symptoms, and provide continuity in remote areas during cycles of insecurity. Effectiveness appears to be mediated by operational requirements for continuous supervision of large community networks, verification of a large number of signals, and integration of community-based surveillance within the routine investigation and response infrastructure. Similar to all community health systems, community-based surveillance requires simple design, reliable supervision, and early and routine monitoring and evaluation to ensure data validity. Research priorities include the evaluation of syndromic case definitions, electronic data collection for community members, sentinel site designs, and statistical techniques to counterbalance false positive signals.
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Affiliation(s)
- Ruwan Ratnayake
- International Rescue Committee, New York, NY, USA; Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK.
| | - Meghan Tammaro
- Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | | | | | - Jonathan A Polonsky
- World Health Organization, Geneva, Switzerland; Institute of Global Health, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Amanda McClelland
- International Federation of Red Cross and Red Crescent Societies, Geneva, Switzerland
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Biggerstaff M, Cowling BJ, Cucunubá ZM, Dinh L, Ferguson NM, Gao H, Hill V, Imai N, Johansson MA, Kada S, Morgan O, Pastore Y Piontti A, Polonsky JA, Prasad PV, Quandelacy TM, Rambaut A, Tappero JW, Vandemaele KA, Vespignani A, Warmbrod KL, Wong JY. Early Insights from Statistical and Mathematical Modeling of Key Epidemiologic Parameters of COVID-19. Emerg Infect Dis 2020; 26:e1-e14. [PMID: 32917290 PMCID: PMC7588530 DOI: 10.3201/eid2611.201074] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
We report key epidemiologic parameter estimates for coronavirus disease identified in peer-reviewed publications, preprint articles, and online reports. Range estimates for incubation period were 1.8–6.9 days, serial interval 4.0–7.5 days, and doubling time 2.3–7.4 days. The effective reproductive number varied widely, with reductions attributable to interventions. Case burden and infection fatality ratios increased with patient age. Implementation of combined interventions could reduce cases and delay epidemic peak up to 1 month. These parameters for transmission, disease severity, and intervention effectiveness are critical for guiding policy decisions. Estimates will likely change as new information becomes available.
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10
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Polonsky JA, Baidjoe A, Kamvar ZN, Cori A, Durski K, Edmunds WJ, Eggo RM, Funk S, Kaiser L, Keating P, de Waroux OLP, Marks M, Moraga P, Morgan O, Nouvellet P, Ratnayake R, Roberts CH, Whitworth J, Jombart T. Outbreak analytics: a developing data science for informing the response to emerging pathogens. Philos Trans R Soc Lond B Biol Sci 2020; 374:20180276. [PMID: 31104603 PMCID: PMC6558557 DOI: 10.1098/rstb.2018.0276] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Despite continued efforts to improve health systems worldwide, emerging pathogen epidemics remain a major public health concern. Effective response to such outbreaks relies on timely intervention, ideally informed by all available sources of data. The collection, visualization and analysis of outbreak data are becoming increasingly complex, owing to the diversity in types of data, questions and available methods to address them. Recent advances have led to the rise of outbreak analytics, an emerging data science focused on the technological and methodological aspects of the outbreak data pipeline, from collection to analysis, modelling and reporting to inform outbreak response. In this article, we assess the current state of the field. After laying out the context of outbreak response, we critically review the most common analytics components, their inter-dependencies, data requirements and the type of information they can provide to inform operations in real time. We discuss some challenges and opportunities and conclude on the potential role of outbreak analytics for improving our understanding of, and response to outbreaks of emerging pathogens. This article is part of the theme issue ‘Modelling infectious disease outbreaks in humans, animals and plants: epidemic forecasting and control‘. This theme issue is linked with the earlier issue ‘Modelling infectious disease outbreaks in humans, animals and plants: approaches and important themes’.
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Affiliation(s)
- Jonathan A Polonsky
- 1 Department of Health Emergency Information and Risk Assessment, World Health Organization , Avenue Appia 20, 1211 Geneva , Switzerland.,3 Faculty of Medicine, University of Geneva , 1 rue Michel-Servet, 1211 Geneva , Switzerland
| | - Amrish Baidjoe
- 4 Department of Infectious Disease Epidemiology, School of Public Health, MRC Centre for Global Infectious Disease Analysis, Imperial College London , Medical School Building, St Mary's Campus, Norfolk Place London W2 1PG , UK
| | - Zhian N Kamvar
- 4 Department of Infectious Disease Epidemiology, School of Public Health, MRC Centre for Global Infectious Disease Analysis, Imperial College London , Medical School Building, St Mary's Campus, Norfolk Place London W2 1PG , UK
| | - Anne Cori
- 4 Department of Infectious Disease Epidemiology, School of Public Health, MRC Centre for Global Infectious Disease Analysis, Imperial College London , Medical School Building, St Mary's Campus, Norfolk Place London W2 1PG , UK
| | - Kara Durski
- 2 Department of Infectious Hazard Management, World Health Organization , Avenue Appia 20, 1211 Geneva , Switzerland
| | - W John Edmunds
- 5 Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine , Keppel St, London WC1E 7HT , UK.,6 Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene and Tropical Medicine , Keppel St, London WC1E 7HT , UK
| | - Rosalind M Eggo
- 5 Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine , Keppel St, London WC1E 7HT , UK.,6 Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene and Tropical Medicine , Keppel St, London WC1E 7HT , UK
| | - Sebastian Funk
- 5 Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine , Keppel St, London WC1E 7HT , UK.,6 Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene and Tropical Medicine , Keppel St, London WC1E 7HT , UK
| | - Laurent Kaiser
- 3 Faculty of Medicine, University of Geneva , 1 rue Michel-Servet, 1211 Geneva , Switzerland
| | - Patrick Keating
- 5 Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine , Keppel St, London WC1E 7HT , UK.,8 UK Public Health Rapid Support Team , London School of Hygiene and Tropical Medicine, Keppel St, London WC1E 7HT , UK
| | - Olivier le Polain de Waroux
- 5 Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine , Keppel St, London WC1E 7HT , UK.,8 UK Public Health Rapid Support Team , London School of Hygiene and Tropical Medicine, Keppel St, London WC1E 7HT , UK.,9 Public Health England , Wellington House, 133-155 Waterloo Road, London SE1 8UG , UK
| | - Michael Marks
- 7 Clinical Research Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine , Keppel St, London WC1E 7HT , UK
| | - Paula Moraga
- 10 Centre for Health Informatics, Computing and Statistics (CHICAS), Lancaster Medical School, Lancaster University , Lancaster LA1 4YW , UK
| | - Oliver Morgan
- 1 Department of Health Emergency Information and Risk Assessment, World Health Organization , Avenue Appia 20, 1211 Geneva , Switzerland
| | - Pierre Nouvellet
- 4 Department of Infectious Disease Epidemiology, School of Public Health, MRC Centre for Global Infectious Disease Analysis, Imperial College London , Medical School Building, St Mary's Campus, Norfolk Place London W2 1PG , UK.,11 School of Life Sciences, University of Sussex , Sussex House, Brighton BN1 9RH , UK
| | - Ruwan Ratnayake
- 5 Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine , Keppel St, London WC1E 7HT , UK.,6 Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene and Tropical Medicine , Keppel St, London WC1E 7HT , UK
| | - Chrissy H Roberts
- 7 Clinical Research Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine , Keppel St, London WC1E 7HT , UK
| | - Jimmy Whitworth
- 5 Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine , Keppel St, London WC1E 7HT , UK.,8 UK Public Health Rapid Support Team , London School of Hygiene and Tropical Medicine, Keppel St, London WC1E 7HT , UK
| | - Thibaut Jombart
- 4 Department of Infectious Disease Epidemiology, School of Public Health, MRC Centre for Global Infectious Disease Analysis, Imperial College London , Medical School Building, St Mary's Campus, Norfolk Place London W2 1PG , UK.,5 Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine , Keppel St, London WC1E 7HT , UK.,8 UK Public Health Rapid Support Team , London School of Hygiene and Tropical Medicine, Keppel St, London WC1E 7HT , UK
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11
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Thompson RN, Stockwin JE, van Gaalen RD, Polonsky JA, Kamvar ZN, Demarsh PA, Dahlqwist E, Li S, Miguel E, Jombart T, Lessler J, Cauchemez S, Cori A. Improved inference of time-varying reproduction numbers during infectious disease outbreaks. Epidemics 2019; 29:100356. [PMID: 31624039 PMCID: PMC7105007 DOI: 10.1016/j.epidem.2019.100356] [Citation(s) in RCA: 238] [Impact Index Per Article: 47.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 07/15/2019] [Accepted: 07/16/2019] [Indexed: 02/07/2023] Open
Abstract
Accurate estimation of the parameters characterising infectious disease transmission is vital for optimising control interventions during epidemics. A valuable metric for assessing the current threat posed by an outbreak is the time-dependent reproduction number, i.e. the expected number of secondary cases caused by each infected individual. This quantity can be estimated using data on the numbers of observed new cases at successive times during an epidemic and the distribution of the serial interval (the time between symptomatic cases in a transmission chain). Some methods for estimating the reproduction number rely on pre-existing estimates of the serial interval distribution and assume that the entire outbreak is driven by local transmission. Here we show that accurate inference of current transmissibility, and the uncertainty associated with this estimate, requires: (i) up-to-date observations of the serial interval to be included, and; (ii) cases arising from local transmission to be distinguished from those imported from elsewhere. We demonstrate how pathogen transmissibility can be inferred appropriately using datasets from outbreaks of H1N1 influenza, Ebola virus disease and Middle-East Respiratory Syndrome. We present a tool for estimating the reproduction number in real-time during infectious disease outbreaks accurately, which is available as an R software package (EpiEstim 2.2). It is also accessible as an interactive, user-friendly online interface (EpiEstim App), permitting its use by non-specialists. Our tool is easy to apply for assessing the transmission potential, and hence informing control, during future outbreaks of a wide range of invading pathogens.
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Affiliation(s)
- R N Thompson
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK; Mathematical Institute, University of Oxford, Radcliffe Observatory Quarter, Woodstock Road, Oxford OX2 6GG, UK; Christ Church, University of Oxford, St Aldates, Oxford OX1 1DP, UK.
| | - J E Stockwin
- Lady Margaret Hall, University of Oxford, Norham Gardens, Oxford OX2 6QA, UK
| | - R D van Gaalen
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), 3720 BA Bilthoven, the Netherlands
| | - J A Polonsky
- World Health Organization, Avenue Appia, Geneva 1202, Switzerland; Faculty of Medicine, University of Geneva, 1 Rue Michel-Servet, Geneva 1211, Switzerland
| | - Z N Kamvar
- MRC Centre for Global Infectious Disease Analysis, Imperial College London, Faculty of Medicine, London W2 1PG, UK
| | - P A Demarsh
- The Surveillance Lab, McGill University, 1140 Pine Avenue West, Montreal H3A 1A3, Canada; Centre for Foodborne, Environmental and Zoonotic Infectious Diseases, Public Health Agency of Canada, 130 Colonnade Road, Ottawa, Ontario, K1A 0K9, Canada
| | - E Dahlqwist
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - S Li
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - E Miguel
- MIVEGEC, IRD, University of Montpellier, CNRS, Montpellier, France
| | - T Jombart
- MRC Centre for Global Infectious Disease Analysis, Imperial College London, Faculty of Medicine, London W2 1PG, UK; Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
| | - J Lessler
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
| | - S Cauchemez
- Mathematical Modelling of Infectious Diseases Unit, Institut Pasteur, UMR2000, CNRS, Paris 75015, France
| | - A Cori
- MRC Centre for Global Infectious Disease Analysis, Imperial College London, Faculty of Medicine, London W2 1PG, UK
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12
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Thompson RN, Stockwin JE, van Gaalen RD, Polonsky JA, Kamvar ZN, Demarsh PA, Dahlqwist E, Li S, Miguel E, Jombart T, Lessler J, Cauchemez S, Cori A. Improved inference of time-varying reproduction numbers during infectious disease outbreaks. Epidemics 2019. [PMID: 31624039 DOI: 10.5281/zenodo.3685977] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/07/2023] Open
Abstract
Accurate estimation of the parameters characterising infectious disease transmission is vital for optimising control interventions during epidemics. A valuable metric for assessing the current threat posed by an outbreak is the time-dependent reproduction number, i.e. the expected number of secondary cases caused by each infected individual. This quantity can be estimated using data on the numbers of observed new cases at successive times during an epidemic and the distribution of the serial interval (the time between symptomatic cases in a transmission chain). Some methods for estimating the reproduction number rely on pre-existing estimates of the serial interval distribution and assume that the entire outbreak is driven by local transmission. Here we show that accurate inference of current transmissibility, and the uncertainty associated with this estimate, requires: (i) up-to-date observations of the serial interval to be included, and; (ii) cases arising from local transmission to be distinguished from those imported from elsewhere. We demonstrate how pathogen transmissibility can be inferred appropriately using datasets from outbreaks of H1N1 influenza, Ebola virus disease and Middle-East Respiratory Syndrome. We present a tool for estimating the reproduction number in real-time during infectious disease outbreaks accurately, which is available as an R software package (EpiEstim 2.2). It is also accessible as an interactive, user-friendly online interface (EpiEstim App), permitting its use by non-specialists. Our tool is easy to apply for assessing the transmission potential, and hence informing control, during future outbreaks of a wide range of invading pathogens.
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Affiliation(s)
- R N Thompson
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK; Mathematical Institute, University of Oxford, Radcliffe Observatory Quarter, Woodstock Road, Oxford OX2 6GG, UK; Christ Church, University of Oxford, St Aldates, Oxford OX1 1DP, UK.
| | - J E Stockwin
- Lady Margaret Hall, University of Oxford, Norham Gardens, Oxford OX2 6QA, UK
| | - R D van Gaalen
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), 3720 BA Bilthoven, the Netherlands
| | - J A Polonsky
- World Health Organization, Avenue Appia, Geneva 1202, Switzerland; Faculty of Medicine, University of Geneva, 1 Rue Michel-Servet, Geneva 1211, Switzerland
| | - Z N Kamvar
- MRC Centre for Global Infectious Disease Analysis, Imperial College London, Faculty of Medicine, London W2 1PG, UK
| | - P A Demarsh
- The Surveillance Lab, McGill University, 1140 Pine Avenue West, Montreal H3A 1A3, Canada; Centre for Foodborne, Environmental and Zoonotic Infectious Diseases, Public Health Agency of Canada, 130 Colonnade Road, Ottawa, Ontario, K1A 0K9, Canada
| | - E Dahlqwist
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - S Li
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - E Miguel
- MIVEGEC, IRD, University of Montpellier, CNRS, Montpellier, France
| | - T Jombart
- MRC Centre for Global Infectious Disease Analysis, Imperial College London, Faculty of Medicine, London W2 1PG, UK; Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
| | - J Lessler
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
| | - S Cauchemez
- Mathematical Modelling of Infectious Diseases Unit, Institut Pasteur, UMR2000, CNRS, Paris 75015, France
| | - A Cori
- MRC Centre for Global Infectious Disease Analysis, Imperial College London, Faculty of Medicine, London W2 1PG, UK
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Karo B, Haskew C, Khan AS, Polonsky JA, Mazhar MKA, Buddha N. World Health Organization Early Warning, Alert and Response System in the Rohingya Crisis, Bangladesh, 2017-2018. Emerg Infect Dis 2018; 24:2074-2076. [PMID: 30234479 PMCID: PMC6199978 DOI: 10.3201/eid2411.181237] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The Early Warning, Alert and Response System (EWARS) is a web-based system and mobile application for outbreak detection and response in emergency settings. EWARS provided timely information on epidemic-potential diseases among >700,000 Rohingya refugees across settlements. EWARS helped in targeting new measles vaccination campaigns and investigating suspected outbreaks of acute jaundice syndrome.
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Polonsky JA, Juan-Giner A, Hurtado N, Masiku C, Kagoli M, Grais RF. Measles seroprevalence in Chiradzulu district, Malawi: Implications for evaluating vaccine coverage. Vaccine 2015. [DOI: 10.1016/j.vaccine.2015.07.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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15
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Polonsky JA, Singh B, Masiku C, Langendorf C, Kagoli M, Hurtado N, Berthelot M, Heinzelmann A, Puren A, Grais RF. Exploring HIV infection and susceptibility to measles among older children and adults in Malawi: a facility-based study. Int J Infect Dis 2014; 31:61-7. [PMID: 25499042 DOI: 10.1016/j.ijid.2014.12.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 11/17/2014] [Accepted: 12/06/2014] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND HIV infection increases measles susceptibility in infants, but little is known about this relationship among older children and adults. We conducted a facility-based study to explore whether HIV status and/or CD4 count were associated with either measles seroprotection and/or measles antibody concentration. METHODS A convenience sample was recruited comprising HIV-infected patients presenting for follow-up care, and HIV-uninfected individuals presenting for HIV testing at Chiradzulu District Hospital, Malawi, from January to September 2012. We recorded age, sex, and reported measles vaccination and infection history. Blood samples were taken to determine the CD4 count and measles antibody concentration. RESULTS One thousand nine hundred and thirty-five participants were recruited (1434 HIV-infected and 501 HIV-uninfected). The majority of adults and approximately half the children were seroprotected against measles, with lower odds among HIV-infected children (adjusted odds ratio 0.27, 95% confidence interval 0.10-0.69; p=0.006), but not adults. Among HIV-infected participants, neither CD4 count (p=0.16) nor time on antiretroviral therapy (p=0.25) were associated with measles antibody concentration, while older age (p<0.001) and female sex (p<0.001) were independently associated with this measure. CONCLUSIONS We found no evidence that HIV infection contributes to the risk of measles infection among adults, but HIV-infected children (including at ages older than previously reported), were less likely to be seroprotected in this sample.
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Affiliation(s)
| | - Beverley Singh
- National Institute for Communicable Diseases/National Health Laboratory Service, Johannesburg, South Africa
| | | | | | | | | | | | | | - Adrian Puren
- National Institute for Communicable Diseases/National Health Laboratory Service, Johannesburg, South Africa; Division of Virology and Communicable Diseases, University of the Witwatersrand, Johannesburg, South Africa
| | - Rebecca F Grais
- Epicentre, Paris, France, 8 rue saint Sabin, 75011 Paris, France
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Polonsky JA, Martínez-Pino I, Nackers F, Chonzi P, Manangazira P, Van Herp M, Maes P, Porten K, Luquero FJ. Descriptive epidemiology of typhoid fever during an epidemic in Harare, Zimbabwe, 2012. PLoS One 2014; 9:e114702. [PMID: 25486292 PMCID: PMC4259398 DOI: 10.1371/journal.pone.0114702] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 11/12/2014] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Typhoid fever remains a significant public health problem in developing countries. In October 2011, a typhoid fever epidemic was declared in Harare, Zimbabwe - the fourth enteric infection epidemic since 2008. To orient control activities, we described the epidemiology and spatiotemporal clustering of the epidemic in Dzivaresekwa and Kuwadzana, the two most affected suburbs of Harare. METHODS A typhoid fever case-patient register was analysed to describe the epidemic. To explore clustering, we constructed a dataset comprising GPS coordinates of case-patient residences and randomly sampled residential locations (spatial controls). The scale and significance of clustering was explored with Ripley K functions. Cluster locations were determined by a random labelling technique and confirmed using Kulldorff's spatial scan statistic. PRINCIPAL FINDINGS We analysed data from 2570 confirmed and suspected case-patients, and found significant spatiotemporal clustering of typhoid fever in two non-overlapping areas, which appeared to be linked to environmental sources. Peak relative risk was more than six times greater than in areas lying outside the cluster ranges. Clusters were identified in similar geographical ranges by both random labelling and Kulldorff's spatial scan statistic. The spatial scale at which typhoid fever clustered was highly localised, with significant clustering at distances up to 4.5 km and peak levels at approximately 3.5 km. The epicentre of infection transmission shifted from one cluster to the other during the course of the epidemic. CONCLUSIONS This study demonstrated highly localised clustering of typhoid fever during an epidemic in an urban African setting, and highlights the importance of spatiotemporal analysis for making timely decisions about targetting prevention and control activities and reinforcing treatment during epidemics. This approach should be integrated into existing surveillance systems to facilitate early detection of epidemics and identify their spatial range.
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Affiliation(s)
| | - Isabel Martínez-Pino
- Epicentre, Paris, France
- European Programme for Intervention Epidemiology Training, European Centre for Disease Prevention and Control, Stockholm, Sweden
| | | | - Prosper Chonzi
- Ministry of Health and Child Welfare, Harare City Health Department, Harare, Zimbabwe
| | - Portia Manangazira
- Ministry of Health and Child Welfare, Epidemiology and Disease Control Directorate, Harare, Zimbabwe
| | - Michel Van Herp
- Médecins Sans Frontières Operational Centre Brussels, Brussels, Belgium
| | - Peter Maes
- Médecins Sans Frontières Operational Centre Brussels, Brussels, Belgium
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17
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Polonsky JA, Wamala JF, de Clerck H, Van Herp M, Sprecher A, Porten K, Shoemaker T. Emerging filoviral disease in Uganda: proposed explanations and research directions. Am J Trop Med Hyg 2014; 90:790-793. [PMID: 24515940 PMCID: PMC4015565 DOI: 10.4269/ajtmh.13-0374] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Accepted: 10/11/2013] [Indexed: 11/19/2022] Open
Abstract
Outbreaks of Ebola and Marburg virus diseases have recently increased in frequency in Uganda. This increase is probably caused by a combination of improved surveillance and laboratory capacity, increased contact between humans and the natural reservoir of the viruses, and fluctuations in viral load and prevalence within this reservoir. The roles of these proposed explanations must be investigated in order to guide appropriate responses to the changing epidemiological profile. Other African settings in which multiple filoviral outbreaks have occurred could also benefit from such information.
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Affiliation(s)
- Jonathan A. Polonsky
- Epicentre, Paris, France; Ministry of Heath, Kampala, Uganda; Médecins Sans Frontières Operational Centre Brussels, Brussels, Belgium; US Centers for Disease Control and Prevention, Entebbe, Uganda
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Polonsky JA, Ronsse A, Ciglenecki I, Rull M, Porten K. High levels of mortality, malnutrition, and measles, among recently-displaced Somali refugees in Dagahaley camp, Dadaab refugee camp complex, Kenya, 2011. Confl Health 2013; 7:1. [PMID: 23339463 PMCID: PMC3607918 DOI: 10.1186/1752-1505-7-1] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Accepted: 01/13/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Following a rapid influx of over 200,000 displaced Somalis into the Dadaab refugee camp complex in Kenya, Médecins Sans Frontières conducted a mortality and nutrition survey of the population living in Bulo Bacte, a self-settled area surrounding Dagahaley camp (part of this complex). METHODS The survey was conducted between 31st July and 10th August 2011. We exhaustively interviewed representatives from all households in Bulo Bacte, collecting information on deaths, births, and population movements during the recall period (15th February 2011 to survey date), in order to provide estimates of retrospective death rates. We recorded the mid-upper arm circumference and presence or absence of bipedal oedema of all children of height 67-<110 cm to provide estimates of global and severe acute malnutrition. RESULTS The surveyed population included 26,583 individuals, of whom 6,488 (24.4%) were children aged under 5 years. There were 360 deaths reported during the 177 days of the recall period, of which 186 (52%) were among children aged under 5 years. The crude death rate for the entire recall period was 0.8 per 10,000 person-days. The under-5 death rate was 1.8 per 10,000 person-days. More than two-thirds of all deaths were reported to have been associated with diarrhoea (25%), cough or other breathing difficulties (24%), or with fever (19%). Measles accounted for a reported 17% of all deaths; this was due to a measles outbreak that occurred between June and October 2011.Global acute malnutrition was observed in 13.4%, and severe acute malnutrition in 3.0%, of children measuring 67-<110 cm. Among children measuring 110-< 140 cm, 9.8% met the admission criteria for entry into the nutritional programme. Trends of decreasing death rates and malnutrition prevalence with length of stay in Bulo Bacte were observed. CONCLUSIONS We report high death rates and prevalence of malnutrition among this population, reflecting at least a partial failure of the various humanitarian and governmental actors to adequately safeguard the welfare of this population. An outbreak of measles and long delays before registration should not have occurred. The recommendations for measles vaccination among crisis-affected populations should be revised to take into account the epidemiologic context. Organisations must be sensitive and reactive to changes in the health status of the populations they assist.
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