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Yang F, Servadio JL, Thanh NTL, Lam HM, Choisy M, Thai PQ, Thao TTN, Vy NHT, Phuong HT, Nguyen TD, Tam DTH, Hanks EM, Vinh H, Bjornstad ON, Chau NVV, Boni MF. A combination of annual and nonannual forces drive respiratory disease in the tropics. BMJ Glob Health 2023; 8:e013054. [PMID: 37935520 PMCID: PMC10632872 DOI: 10.1136/bmjgh-2023-013054] [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: 06/06/2023] [Accepted: 10/08/2023] [Indexed: 11/09/2023] Open
Abstract
INTRODUCTION It is well known that influenza and other respiratory viruses are wintertime-seasonal in temperate regions. However, respiratory disease seasonality in the tropics is less well understood. In this study, we aimed to characterise the seasonality of influenza-like illness (ILI) and influenza virus in Ho Chi Minh City, Vietnam. METHODS We monitored the daily number of ILI patients in 89 outpatient clinics from January 2010 to December 2019. We collected nasal swabs and tested for influenza from a subset of clinics from May 2012 to December 2019. We used spectral analysis to describe the periodic signals in the system. We evaluated the contribution of these periodic signals to predicting ILI and influenza patterns through lognormal and gamma hurdle models. RESULTS During 10 years of community surveillance, 66 799 ILI reports were collected covering 2.9 million patient visits; 2604 nasal swabs were collected, 559 of which were PCR-positive for influenza virus. Both annual and nonannual cycles were detected in the ILI time series, with the annual cycle showing 8.9% lower ILI activity (95% CI 8.8% to 9.0%) from February 24 to May 15. Nonannual cycles had substantial explanatory power for ILI trends (ΔAIC=183) compared with all annual covariates (ΔAIC=263) in lognormal regression. Near-annual signals were observed for PCR-confirmed influenza but were not consistent over time or across influenza (sub)types. The explanatory power of climate factors for ILI and influenza virus trends was weak. CONCLUSION Our study reveals a unique pattern of respiratory disease dynamics in a tropical setting influenced by both annual and nonannual drivers, with influenza dynamics showing near-annual periodicities. Timing of vaccination campaigns and hospital capacity planning may require a complex forecasting approach.
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Affiliation(s)
- Fuhan Yang
- Department of Biology and Center for Infectious Disease Dynamics, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Joseph L Servadio
- Department of Biology and Center for Infectious Disease Dynamics, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Nguyen Thi Le Thanh
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Ha Minh Lam
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Marc Choisy
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Pham Quang Thai
- National Institute of Hygiene and Epidemiology, Hanoi, Vietnam
| | - Tran Thi Nhu Thao
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Nguyen Ha Thao Vy
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Huynh Thi Phuong
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Tran Dang Nguyen
- Department of Biology and Center for Infectious Disease Dynamics, The Pennsylvania State University, University Park, Pennsylvania, USA
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Dong Thi Hoai Tam
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Ephraim M Hanks
- Department of Statistics and Center for Infectious Disease Dynamics, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Ha Vinh
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Ottar N Bjornstad
- Department of Biology and Center for Infectious Disease Dynamics, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Nguyen Van Vinh Chau
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Maciej F Boni
- Department of Biology and Center for Infectious Disease Dynamics, The Pennsylvania State University, University Park, Pennsylvania, USA
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
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Liang Y, Sun Z, Hua W, Li D, Han L, Liu J, Huo L, Zhang H, Zhang S, Zhao Y, He X. Spatiotemporal effects of meteorological conditions on global influenza peaks. ENVIRONMENTAL RESEARCH 2023; 231:116171. [PMID: 37230217 DOI: 10.1016/j.envres.2023.116171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 05/01/2023] [Accepted: 05/15/2023] [Indexed: 05/27/2023]
Abstract
BACKGROUND Numerous studies have suggested that meteorological conditions such as temperature and absolute humidity are highly indicative of influenza outbreaks. However, the explanatory power of meteorological factors on the seasonal influenza peaks varied widely between countries at different latitudes. OBJECTIVES We aimed to explore the modification effects of meteorological factors on the seasonal influenza peaks in multi-countries. METHODS Data on influenza positive rate (IPR) were collected across 57 countries and data on meteorological factors were collected from ECMWF Reanalysis v5 (ERA5). We used linear regression and generalized additive models to investigate the spatiotemporal associations between meteorological conditions and influenza peaks in cold and warm seasons. RESULTS Influenza peaks were significantly correlated with months with both lower and higher temperatures. In temperate countries, the average intensity of cold season peaks was stronger than that of warm season peaks. However, the average intensity of warm season peaks was stronfger than of cold season peaks in tropical countries. Temperature and specific humidity had synergistic effects on influenza peaks at different latitudes, stronger in temperate countries (cold season: R2=0.90; warm season: R2=0.84) and weaker in tropical countries (cold season: R2=0.64; warm season: R2=0.03). Furthermore, the effects could be divided into cold-dry and warm-humid modes. The temperature transition threshold between the two modes was 16.5-19.5 °C. During the transition from cold-dry mode to warm-humid mode, the average 2 m specific humidity increased by 2.15 times, illustrating that transporting a large amount of water vapor may compensate for the negative effect of rising temperatures on the spread of the influenza virus. CONCLUSION Differences in the global influenza peaks were related to the synergistic influence of temperature and specific humidity. The global influenza peaks could be divided into cold-dry and warm-humid modes, and specific thresholds of meteorological conditions were needed for the transition of the two modes.
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Affiliation(s)
- Yinglin Liang
- School of Atmospheric Sciences, Chengdu University of Information Technology, Chengdu, 610225, China; State Key Laboratory of Severe Weather (LASW), Chinese Academy of Meteorological Sciences (CAMS), CMA, Beijing, 100081, China; Key Laboratory of Urban Meteorology, China Meteorological Administration, Beijing, 100089, China
| | - Zhaobin Sun
- State Key Laboratory of Severe Weather (LASW), Chinese Academy of Meteorological Sciences (CAMS), CMA, Beijing, 100081, China; Key Laboratory of Urban Meteorology, China Meteorological Administration, Beijing, 100089, China.
| | - Wei Hua
- School of Atmospheric Sciences, Chengdu University of Information Technology, Chengdu, 610225, China.
| | - Demin Li
- National Clinical Research Center for Respiratory Diseases, China-Japan Friendship Hospital, 100192, China
| | - Ling Han
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, 102206, China
| | - Jian Liu
- Cardiology Department, Peking University People's Hospital, Beijing, 100044, China
| | - Liming Huo
- Cardiology Department, Peking University People's Hospital, Beijing, 100044, China
| | - Hongchun Zhang
- National Clinical Research Center for Respiratory Diseases, China-Japan Friendship Hospital, 100192, China
| | - Shuwen Zhang
- State Key Laboratory of Severe Weather (LASW), Chinese Academy of Meteorological Sciences (CAMS), CMA, Beijing, 100081, China
| | - Yuxin Zhao
- State Key Laboratory of Severe Weather (LASW), Chinese Academy of Meteorological Sciences (CAMS), CMA, Beijing, 100081, China
| | - Xiaonan He
- Emergency Critical Care Center, Beijing AnZhen Hospital, Capital Medical University, Beijing, 100029, China
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Servadio JL, Thai PQ, Choisy M, Boni MF. Repeatability and timing of tropical influenza epidemics. PLoS Comput Biol 2023; 19:e1011317. [PMID: 37467254 PMCID: PMC10389745 DOI: 10.1371/journal.pcbi.1011317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 06/29/2023] [Indexed: 07/21/2023] Open
Abstract
Much of the world experiences influenza in yearly recurring seasons, particularly in temperate areas. These patterns can be considered repeatable if they occur predictably and consistently at the same time of year. In tropical areas, including southeast Asia, timing of influenza epidemics is less consistent, leading to a lack of consensus regarding whether influenza is repeatable. This study aimed to assess repeatability of influenza in Vietnam, with repeatability defined as seasonality that occurs at a consistent time of year with low variation. We developed a mathematical model incorporating parameters to represent periods of increased transmission and then fitted the model to data collected from sentinel hospitals throughout Vietnam as well as four temperate locations. We fitted the model for individual (sub)types of influenza as well as all combined influenza throughout northern, central, and southern Vietnam. Repeatability was evaluated through the variance of the timings of peak transmission. Model fits from Vietnam show high variance (sd = 64-179 days) in peak transmission timing, with peaks occurring at irregular intervals and throughout different times of year. Fits from temperate locations showed regular, annual epidemics in winter months, with low variance in peak timings (sd = 32-57 days). This suggests that influenza patterns are not repeatable or seasonal in Vietnam. Influenza prevention in Vietnam therefore cannot rely on anticipation of regularly occurring outbreaks.
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Affiliation(s)
- Joseph L Servadio
- Center for Infectious Disease Dynamics and Department of Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Pham Quang Thai
- National Institute of Hygiene and Epidemiology, Hanoi, Vietnam
- School of Preventative Medicine and Public Health, Hanoi Medical University, Hanoi, Vietnam
| | - Marc Choisy
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Maciej F Boni
- Center for Infectious Disease Dynamics and Department of Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
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Igboh LS, Roguski K, Marcenac P, Emukule GO, Charles MD, Tempia S, Herring B, Vandemaele K, Moen A, Olsen SJ, Wentworth DE, Kondor R, Mott JA, Hirve S, Bresee JS, Mangtani P, Nguipdop-Djomo P, Azziz-Baumgartner E. Timing of seasonal influenza epidemics for 25 countries in Africa during 2010-19: a retrospective analysis. Lancet Glob Health 2023; 11:e729-e739. [PMID: 37061311 PMCID: PMC10126228 DOI: 10.1016/s2214-109x(23)00109-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Revised: 02/06/2023] [Accepted: 02/20/2023] [Indexed: 04/17/2023]
Abstract
BACKGROUND Using country-specific surveillance data to describe influenza epidemic activity could inform decisions on the timing of influenza vaccination. We analysed surveillance data from African countries to characterise the timing of seasonal influenza epidemics to inform national vaccination strategies. METHODS We used publicly available sentinel data from African countries reporting to the WHO Global Influenza Surveillance and Response FluNet platform that had 3-10 years of data collected during 2010-19. We calculated a 3-week moving proportion of samples positive for influenza virus and assessed epidemic timing using an aggregate average method. The start and end of each epidemic were defined as the first week when the proportion of positive samples exceeded or went below the annual mean, respectively, for at least 3 consecutive weeks. We categorised countries into five epidemic patterns: northern hemisphere-dominant, with epidemics occurring in October-March; southern hemisphere-dominant, with epidemics occurring in April-September; primarily northern hemisphere with some epidemic activity in southern hemisphere months; primarily southern hemisphere with some epidemic activity in northern hemisphere months; and year-round influenza transmission without a discernible northern hemisphere or southern hemisphere predominance (no clear pattern). FINDINGS Of the 34 countries reporting data to FluNet, 25 had at least 3 years of data, representing 46% of the countries in Africa and 89% of Africa's population. Study countries reported RT-PCR respiratory virus results for a total of 503 609 specimens (median 12 971 [IQR 9607-20 960] per country-year), of which 74 001 (15%; median 2078 [IQR 1087-3008] per country-year) were positive for influenza viruses. 248 epidemics occurred across 236 country-years of data (median 10 [range 7-10] per country). Six (24%) countries had a northern hemisphere pattern (Algeria, Burkina Faso, Egypt, Morocco, Niger, and Tunisia). Eight (32%) had a primarily northern hemisphere pattern with some southern hemisphere epidemics (Cameroon, Ethiopia, Mali, Mozambique, Nigeria, Senegal, Tanzania, and Togo). Three (12%) had a primarily southern hemisphere pattern with some northern hemisphere epidemics (Ghana, Kenya, and Uganda). Three (12%) had a southern hemisphere pattern (Central African Republic, South Africa, and Zambia). Five (20%) had no clear pattern (Côte d'Ivoire, DR Congo, Madagascar, Mauritius, and Rwanda). INTERPRETATION Most countries had identifiable influenza epidemic periods that could be used to inform authorities of non-seasonal and seasonal influenza activity, guide vaccine timing, and promote timely interventions. FUNDING None. TRANSLATIONS For the Berber, Luganda, Xhosa, Chewa, Yoruba, Igbo, Hausa and Afan Oromo translations of the abstract see Supplementary Materials section.
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Affiliation(s)
- Ledor S Igboh
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA; Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, London, UK; Immunization Systems Branch, Global Immunization Division, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA.
| | - Katherine Roguski
- National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Perrine Marcenac
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | | | - Myrna D Charles
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Stefano Tempia
- School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; Department of Infectious Hazard Management, World Health Organization, Geneva, Switzerland
| | - Belinda Herring
- World Health Organization-Regional Office for Africa, Brazzaville, Congo
| | - Katelijn Vandemaele
- Department of Infectious Hazard Management, World Health Organization, Geneva, Switzerland
| | - Ann Moen
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Sonja J Olsen
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - David E Wentworth
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Rebecca Kondor
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Josh A Mott
- Department of Infectious Hazard Management, World Health Organization, Geneva, Switzerland
| | - Siddhivinayak Hirve
- Department of Infectious Hazard Management, World Health Organization, Geneva, Switzerland
| | | | - Punam Mangtani
- Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, London, UK
| | - Patrick Nguipdop-Djomo
- Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, London, UK
| | - Eduardo Azziz-Baumgartner
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
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Du M, Zhu H, Yin X, Ke T, Gu Y, Li S, Li Y, Zheng G. Exploration of influenza incidence prediction model based on meteorological factors in Lanzhou, China, 2014-2017. PLoS One 2022; 17:e0277045. [PMID: 36520836 PMCID: PMC9754291 DOI: 10.1371/journal.pone.0277045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 10/19/2022] [Indexed: 12/23/2022] Open
Abstract
Humans are susceptible to influenza. The influenza virus spreads quickly and behave seasonally. The seasonality and spread of influenza are often associated with meteorological factors and have spatio-temporal differences. Based on the influenza cases and daily average meteorological factors in Lanzhou from 2014 to 2017, this study firstly aimed to analyze the characteristics of influenza incidence in Lanzhou and the impact of meteorological factors on influenza activities. Then, SARIMA(X) models for the prediction were established. The influenza cases in Lanzhou from 2014 to 2017 was more male than female, and the younger the age, the higher the susceptibility; the epidemic characteristics showed that there is a peak in winter, a secondary peak in spring, and a trough in summer and autumn. The influenza cases in Lanzhou increased with increasing daily pressure, decreasing precipitation, average relative humidity, hours of sunshine, average daily temperature and average daily wind speed. Low temperature was a significant driving factor for the increase of transmission intensity of seasonal influenza. The SARIMAX (1,0,0)(1,0,1)[12] multivariable model with average temperature has better prediction performance than the university model. This model is helpful to establish an early warning system, and provide important evidence for the development of influenza control policies and public health interventions.
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Affiliation(s)
- Meixia Du
- School of Public Health, Gansu University of Chinese Medicine, Gansu Lanzhou, China
- Gansu Provincial Cancer Hospital, Gansu Lanzhou, China
| | - Hai Zhu
- School of Public Health, Gansu University of Chinese Medicine, Gansu Lanzhou, China
| | - Xiaochun Yin
- School of Public Health, Gansu University of Chinese Medicine, Gansu Lanzhou, China
- The Collaborative Innovation Center for Prevention and Control by Chinese Medicine on Disease Related Northwestern Environment and Nutrition, Gansu Lanzhou, China
- * E-mail: (XY); (SL)
| | - Ting Ke
- School of Public Health, Gansu University of Chinese Medicine, Gansu Lanzhou, China
| | - Yonge Gu
- School of Public Health, Gansu University of Chinese Medicine, Gansu Lanzhou, China
- The Collaborative Innovation Center for Prevention and Control by Chinese Medicine on Disease Related Northwestern Environment and Nutrition, Gansu Lanzhou, China
| | - Sheng Li
- First People’s Hospital of Lanzhou City, Gansu Lanzhou, China
- * E-mail: (XY); (SL)
| | - Yongjun Li
- Gansu Provincial Center for Disease Control and Prevention, Gansu Lanzhou, China
| | - Guisen Zheng
- School of Public Health, Gansu University of Chinese Medicine, Gansu Lanzhou, China
- The Collaborative Innovation Center for Prevention and Control by Chinese Medicine on Disease Related Northwestern Environment and Nutrition, Gansu Lanzhou, China
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Belizaire MRD, N’gattia AK, Wassonguema B, Simaleko MM, Nakoune E, Rafaï C, Lô B, Bolumar F. Circulation and seasonality of influenza viruses in different transmission zones in Africa. BMC Infect Dis 2022; 22:820. [DOI: 10.1186/s12879-022-07727-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 06/15/2022] [Indexed: 11/09/2022] Open
Abstract
Abstract
Background
Influenza is responsible for more than 5 million severe cases and 290,000 to 650,000 deaths every year worldwide. Developing countries account for 99% of influenza deaths in children under 5 years of age. This paper aimed to determine the dynamics of influenza viruses in African transmission areas to identify regional seasonality for appropriate decision-making and the development of regional preparedness and response strategies.
Methods
We used data from the WHO FluMart website collected by National Influenza Centers for seven transmission periods (2013–2019). We calculated weekly proportions of positive influenza cases and determined transmission trends in African countries to determine the seasonality.
Results
From 2013 to 2019, influenza A(H1N1)pdm2009, A(H3N2), and A(H5N1) viruses, as well as influenza B Victoria and Yamagata lineages, circulated in African regions. Influenza A(H1N1)pdm2009 and A(H3N2) highly circulated in northern and southern Africa regions. Influenza activity followed annual and regional variations. In the tropical zone, from eastern to western via the middle regions, influenza activities were marked by the predominance of influenza A subtypes despite the circulation of B lineages. One season was identified for both the southern and northern regions of Africa. In the eastern zone, four influenza seasons were differentiated, and three were differentiated in the western zone.
Conclusion
Circulation dynamics determined five intense influenza activity zones in Africa. In the tropics, influenza virus circulation waves move from the east to the west, while alternative seasons have been identified in northern and southern temperate zones. Health authorities from countries with the same transmission zone, even in the absence of local data based on an established surveillance system, should implement concerted preparedness and control activities, such as vaccination.
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Randremanana RV, Andriamandimby S, Rakotondramanga JM, Razanajatovo NH, Mangahasimbola RT, Randriambolamanantsoa TH, Ranaivoson HC, Rabemananjara HA, Razanajatovo I, Razafindratsimandresy R, Rabarison JH, Brook CE, Rakotomanana F, Rabetombosoa RM, Razafimanjato H, Ahyong V, Raharinosy V, Raharimanga V, Raharinantoanina SJ, Randrianarisoa MM, Bernardson B, Randrianasolo L, Randriamampionona LBN, Tato CM, DeRisi JL, Dussart P, Vololoniaina MC, Randriatsarafara FM, Randriamanantany ZA, Heraud J. The COVID-19 epidemic in Madagascar: clinical description and laboratory results of the first wave, march-september 2020. Influenza Other Respir Viruses 2021; 15:457-468. [PMID: 33586912 PMCID: PMC8013501 DOI: 10.1111/irv.12845] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 01/25/2021] [Accepted: 01/29/2021] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Following the first detection of SARS-CoV-2 in passengers arriving from Europe on 19 March 2020, Madagascar took several mitigation measures to limit the spread of the virus in the country. METHODS Nasopharyngeal and/or oropharyngeal swabs were collected from travellers to Madagascar, suspected SARS-CoV-2 cases and contact of confirmed cases. Swabs were tested at the national reference laboratory using real-time RT-PCR. Data collected from patients were entered in an electronic database for subsequent statistical analysis. All distribution of laboratory-confirmed cases were mapped, and six genomes of viruses were fully sequenced. RESULTS Overall, 26,415 individuals were tested for SARS-CoV-2 between 18 March and 18 September 2020, of whom 21.0% (5,553/26,145) returned positive. Among laboratory-confirmed SARS-CoV-2-positive patients, the median age was 39 years (IQR: 28-52), and 56.6% (3,311/5,553) were asymptomatic at the time of sampling. The probability of testing positive increased with age with the highest adjusted odds ratio of 2.2 [95% CI: 1.9-2.5] for individuals aged 49 years and more. Viral strains sequenced belong to clades 19A, 20A and 20B indicative of several independent introduction of viruses. CONCLUSIONS Our study describes the first wave of the COVID-19 in Madagascar. Despite early strategies in place Madagascar could not avoid the introduction and spread of the virus. More studies are needed to estimate the true burden of disease and make public health recommendations for a better preparation to another wave.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | - Fanjasoa Rakotomanana
- Epidemiology and Clinical Research UnitInstitut Pasteur de MadagascarAntananarivoMadagascar
| | | | | | | | | | - Vaomalala Raharimanga
- Epidemiology and Clinical Research UnitInstitut Pasteur de MadagascarAntananarivoMadagascar
| | | | | | - Barivola Bernardson
- Epidemiology and Clinical Research UnitInstitut Pasteur de MadagascarAntananarivoMadagascar
| | - Laurence Randrianasolo
- Epidemiology and Clinical Research UnitInstitut Pasteur de MadagascarAntananarivoMadagascar
| | | | | | | | - Philippe Dussart
- Virology UnitInstitut Pasteur de MadagascarAntananarivoMadagascar
| | | | | | | | - Jean‐Michel Heraud
- Virology UnitInstitut Pasteur de MadagascarAntananarivoMadagascar
- Present address:
Virology DepartmentInstitut Pasteur de DakarDakarSenegal
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Lagare A, Rajatonirina S, Testa J, Mamadou S. The epidemiology of seasonal influenza after the 2009 influenza pandemic in Africa: a systematic review. Afr Health Sci 2020; 20:1514-1536. [PMID: 34394213 PMCID: PMC8351825 DOI: 10.4314/ahs.v20i4.5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Background Influenza infection is a serious public health problem that causes an estimated 3 to 5 million cases and 250,000 deaths worldwide every year. The epidemiology of influenza is well-documented in high- and middle-income countries, however minimal effort had been made to understand the epidemiology, burden and seasonality of influenza in Africa. This study aims to assess the state of knowledge of seasonal influenza epidemiology in Africa and identify potential data gaps for policy formulation following the 2009 pandemic. Method We reviewed articles from Africa published into four databases namely: MEDLINE (PubMed), Google Scholar, Cochrane Library and Scientific Research Publishing from 2010 to 2019. Results We screened titles and abstracts of 2070 studies of which 311 were selected for full content evaluation and 199 studies were considered. Selected articles varied substantially on the basis of the topics they addressed covering the field of influenza surveillance (n=80); influenza risk factors and co-morbidities (n=15); influenza burden (n=37); influenza vaccination (n=40); influenza and other respiratory pathogens (n=22) and influenza diagnosis (n=5). Conclusion Significant progress has been made since the last pandemic in understanding the influenza epidemiology in Africa. However, efforts still remain for most countries to have sufficient data to allow countries to prioritize strategies for influenza prevention and control.
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Affiliation(s)
- Adamou Lagare
- Centre de Recherche Médicale et Sanitaire (CERMES), Niamey, Niger
| | | | - Jean Testa
- Centre de Recherche Médicale et Sanitaire (CERMES), Niamey, Niger
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9
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Dave K, Lee PC. Global Geographical and Temporal Patterns of Seasonal Influenza and Associated Climatic Factors. Epidemiol Rev 2020; 41:51-68. [PMID: 31565734 DOI: 10.1093/epirev/mxz008] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Revised: 05/11/2019] [Accepted: 09/04/2019] [Indexed: 11/13/2022] Open
Abstract
Understanding geographical and temporal patterns of seasonal influenza can help strengthen influenza surveillance to early detect epidemics and inform influenza prevention and control programs. We examined variations in spatiotemporal patterns of seasonal influenza in different global regions and explored climatic factors that influence differences in influenza seasonality, through a systematic review of peer-reviewed publications. The literature search was conducted to identify original studies published between January 2005 and November 2016. Studies were selected using predetermined inclusion and exclusion criteria. The primary outcome was influenza cases; additional outcomes included seasonal or temporal patterns of influenza seasonality, study regions (temperate or tropical), and associated climatic factors. Of the 2,160 records identified in the selection process, 36 eligible studies were included. There were significant differences in influenza seasonality in terms of the time of onset, duration, number of peaks, and amplitude of epidemics between temperate and tropical/subtropical regions. Different viral types, cocirculation of influenza viruses, and climatic factors, especially temperature and absolute humidity, contributed to the variations in spatiotemporal patterns of seasonal influenza. The findings reported in this review could inform global surveillance of seasonal influenza and influenza prevention and control measures such as vaccination recommendations for different regions.
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Affiliation(s)
- Kunjal Dave
- Bioscience Department, Endeavour College of Natural Health, Brisbane, Queensland, Australia
| | - Patricia C Lee
- School of Medicine, Griffith University, Gold Coast, Queensland, Australia.,Menzies Health Institute, Queensland, Australia.,Department of Medical Research, China Medical University Hospital, China Medical University, Taichung City, Taiwan
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Heraud JM, Razanajatovo NH, Viboud C. Global circulation of respiratory viruses: from local observations to global predictions. LANCET GLOBAL HEALTH 2020; 7:e982-e983. [PMID: 31303303 DOI: 10.1016/s2214-109x(19)30277-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 05/30/2019] [Indexed: 10/26/2022]
Affiliation(s)
- Jean-Michel Heraud
- National Influenza Centre, Virology Unit, Institut Pasteur de Madagascar, Antananarivo 101, Madagascar.
| | | | - Cecile Viboud
- Division of International Epidemiology and Population Studies, Fogarty International Center, National Institutes of Health, Bethesda, MD, USA
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11
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Fogarty International Center collaborative networks in infectious disease modeling: Lessons learnt in research and capacity building. Epidemics 2019; 26:116-127. [PMID: 30446431 PMCID: PMC7105018 DOI: 10.1016/j.epidem.2018.10.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 08/06/2018] [Accepted: 10/17/2018] [Indexed: 12/24/2022] Open
Abstract
Due to a combination of ecological, political, and demographic factors, the emergence of novel pathogens has been increasingly observed in animals and humans in recent decades. Enhancing global capacity to study and interpret infectious disease surveillance data, and to develop data-driven computational models to guide policy, represents one of the most cost-effective, and yet overlooked, ways to prepare for the next pandemic. Epidemiological and behavioral data from recent pandemics and historic scourges have provided rich opportunities for validation of computational models, while new sequencing technologies and the 'big data' revolution present new tools for studying the epidemiology of outbreaks in real time. For the past two decades, the Division of International Epidemiology and Population Studies (DIEPS) of the NIH Fogarty International Center has spearheaded two synergistic programs to better understand and devise control strategies for global infectious disease threats. The Multinational Influenza Seasonal Mortality Study (MISMS) has strengthened global capacity to study the epidemiology and evolutionary dynamics of influenza viruses in 80 countries by organizing international research activities and training workshops. The Research and Policy in Infectious Disease Dynamics (RAPIDD) program and its precursor activities has established a network of global experts in infectious disease modeling operating at the research-policy interface, with collaborators in 78 countries. These activities have provided evidence-based recommendations for disease control, including during large-scale outbreaks of pandemic influenza, Ebola and Zika virus. Together, these programs have coordinated international collaborative networks to advance the study of emerging disease threats and the field of computational epidemic modeling. A global community of researchers and policy-makers have used the tools and trainings developed by these programs to interpret infectious disease patterns in their countries, understand modeling concepts, and inform control policies. Here we reflect on the scientific achievements and lessons learnt from these programs (h-index = 106 for RAPIDD and 79 for MISMS), including the identification of outstanding researchers and fellows; funding flexibility for timely research workshops and working groups (particularly relative to more traditional investigator-based grant programs); emphasis on group activities such as large-scale modeling reviews, model comparisons, forecasting challenges and special journal issues; strong quality control with a light touch on outputs; and prominence of training, data-sharing, and joint publications.
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12
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Almeida A, Codeço C, Luz PM. Seasonal dynamics of influenza in Brazil: the latitude effect. BMC Infect Dis 2018; 18:695. [PMID: 30587159 PMCID: PMC6307116 DOI: 10.1186/s12879-018-3484-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 10/31/2018] [Indexed: 10/27/2022] Open
Abstract
BACKGROUND Influenza is a global transmissible disease. Its dynamics is far better understood in temperate climates than in the tropics. We aim to close this knowledge gap between tropical and temperate regions by showing how the influenza seasonality evolves in Brazil, a tropical country that encompasses a wide range of latitudes and six climatic sub-types. METHODS We analyzed a state-level, weekly Syndrome of Acute Respiratory Disease (SARI) incidence data ranging from 2010 to 2016. We combined two techniques hierarchically: first the wavelet decomposition technique to detect annual periodicity and then circular statistics to describe seasonal measures of the periodic states. RESULTS We found significant annual periodicity in 44% of the states. For these, we calculated several seasonal measures such as the center of gravity or mean timing of activity. The relationship between the seasonal signatures and latitude was clear and statistically significant. States with seasonal signature are clustered along the coast. Most Amazonian and Central West states exhibit no seasonal behavior. Among the seasonal states, influenza starts in Northeast region, spreading southbound. CONCLUSIONS Our study advances the comprehension of influenza seasonality in tropical areas and could be used to design more effective prevention and control strategies.
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Affiliation(s)
- Alexandra Almeida
- Escola Nacional de Saúde Pública, FIOCRUZ, Rio de Janeiro, Brazil. .,Programa de Computação Científica, FIOCRUZ, Rio de Janeiro, Brasil.
| | - Cláudia Codeço
- Programa de Computação Científica, FIOCRUZ, Rio de Janeiro, Brasil
| | - Paula M Luz
- Instituto Nacional de Infectologia Evandro Chagas, FIOCRUZ, Rio de Janeiro, Brasil
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13
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Guillebaud J, Héraud JM, Razanajatovo NH, Livinski AA, Alonso WJ. Both hemispheric influenza vaccine recommendations would have missed near half of the circulating viruses in Madagascar. Influenza Other Respir Viruses 2018; 11:473-478. [PMID: 29067783 PMCID: PMC5705694 DOI: 10.1111/irv.12517] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/14/2017] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND Influenza immunization still poses a critical challenge globally and specifically for tropical regions due to their complex influenza circulation pattern. Tropical regions should select the WHO's Northern Hemisphere or Southern Hemisphere recommended vaccine composition based on local surveillance. Analyses of influenza immunization effectiveness have neglected to account for the proportion of circulating viruses prevented from causing infection each year. We investigate this question for Madagascar, where influenza vaccines are not widely available. METHODS Seventy-eight Malagasy influenza strains characterized from 2002 to 2014 were challenged with hypothetical scenarios in which the WHO's Northern Hemisphere and Southern Hemisphere recommended vaccine compositions were provided to the population. Match between circulating and vaccine strains was determined by haemagglutination inhibition assays. Strain-specific positive matches were scored assuming 9 months of protection, and scenarios incorporated vaccine delays from zero to 5 months. RESULTS Malagasy influenza strains matched 54% and 44%, respectively, with the Northern Hemisphere and Southern Hemisphere recommended vaccine strains when the vaccine was delivered as soon as available. The matching values further decreased when additional delivery and application delays were considered. Differences between recommended compositions were not statistically significant. CONCLUSION Our results showed matching with the Northern Hemisphere vaccine barely above 50%, even in the more favourable scenario. This suggests that if implemented, routine influenza vaccines would not provide an optimal protection against half of the influenza strains circulating in any epidemic season of Madagascar. We suggest that this limitation in influenza vaccine efficacy deserves greater attention, and should be considered in cost/benefit analyses of national influenza immunization programmes.
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Affiliation(s)
- Julia Guillebaud
- National Influenza Centre, Virology Unit, Institut Pasteur de Madagascar, Antananarivo, Madagascar
| | - Jean-Michel Héraud
- National Influenza Centre, Virology Unit, Institut Pasteur de Madagascar, Antananarivo, Madagascar
| | - Norosoa H Razanajatovo
- National Influenza Centre, Virology Unit, Institut Pasteur de Madagascar, Antananarivo, Madagascar
| | - Alicia A Livinski
- National Institutes of Health Library, Office of Research Services, Office of Management, National Institutes of Health, Bethesda, MD, USA
| | - Wladimir J Alonso
- Laboratory for Human Evolutionary and Ecological Studies, Institute of Biosciences, University of São Paulo, São Paulo, Brazil
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Yang W, Cummings MJ, Bakamutumaho B, Kayiwa J, Owor N, Namagambo B, Byaruhanga T, Lutwama JJ, O'Donnell MR, Shaman J. Dynamics of influenza in tropical Africa: Temperature, humidity, and co-circulating (sub)types. Influenza Other Respir Viruses 2018; 12:446-456. [PMID: 29573157 PMCID: PMC6005592 DOI: 10.1111/irv.12556] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/24/2018] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND The association of influenza with meteorological variables in tropical climates remains controversial. Here, we investigate the impact of weather conditions on influenza in the tropics and factors that may contribute to this uncertainty. METHODS We computed the monthly viral positive rate for each of the 3 circulating influenza (sub)types (ie, A/H1N1, A/H3N2, and B) among patients presenting with influenza-like illness (ILI) or severe acute respiratory infections (SARI) in 2 Ugandan cities (Entebbe and Kampala). Using this measure as a proxy for influenza activity, we applied regression models to examine the impact of temperature, relative humidity, absolute humidity, and precipitation, as well as interactions among the 3 influenza viruses on the epidemic dynamics of each influenza (sub)type. A full analysis including all 4 weather variables was done for Entebbe during 2007-2015, and a partial analysis including only temperature and precipitation was done for both cities during 2008-2014. RESULTS For Entebbe, the associations with weather variables differed by influenza (sub)type; with adjustment for viral interactions, the models showed that precipitation and temperature were negatively correlated with A/H1N1 activity, but not for A/H3N2 or B. A mutually negative association between A/H3N2 and B activity was identified in both Entebbe and Kampala. CONCLUSION Our findings suggest that key interactions exist among influenza (sub)types at the population level in the tropics and that such interactions can modify the association of influenza activity with weather variables. Studies of the relationship between influenza and weather conditions should therefore determine and account for co-circulating influenza (sub)types.
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Affiliation(s)
- Wan Yang
- Department of Environmental Health SciencesColumbia UniversityNew YorkNYUSA
| | - Matthew J. Cummings
- Division of Pulmonary, Allergy, and Critical Care MedicineColumbia UniversityNew YorkNYUSA
| | | | - John Kayiwa
- National Influenza CenterUganda Virus Research InstituteEntebbeUganda
| | - Nicholas Owor
- National Influenza CenterUganda Virus Research InstituteEntebbeUganda
| | - Barbara Namagambo
- National Influenza CenterUganda Virus Research InstituteEntebbeUganda
| | | | - Julius J. Lutwama
- National Influenza CenterUganda Virus Research InstituteEntebbeUganda
| | - Max R. O'Donnell
- Division of Pulmonary, Allergy, and Critical Care MedicineColumbia UniversityNew YorkNYUSA
- Department of EpidemiologyColumbia UniversityNew YorkNYUSA
| | - Jeffrey Shaman
- Department of Environmental Health SciencesColumbia UniversityNew YorkNYUSA
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Caini S, El‐Guerche Séblain C, Ciblak MA, Paget J. Epidemiology of seasonal influenza in the Middle East and North Africa regions, 2010-2016: Circulating influenza A and B viruses and spatial timing of epidemics. Influenza Other Respir Viruses 2018; 12:344-352. [PMID: 29405575 PMCID: PMC5907816 DOI: 10.1111/irv.12544] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/14/2017] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND There is a limited knowledge regarding the epidemiology of influenza in Middle East and North Africa. OBJECTIVES We described the patterns of influenza circulation and the timing of seasonal epidemics in countries of Middle East and North Africa. METHODS We used virological surveillance data for 2010-2016 from the WHO FluNet database. In each country, we calculated the median proportion of cases that were caused by each virus type and subtype; determined the timing and amplitude of the primary and secondary peaks; and used linear regression models to test for spatial trends in the timing of epidemics. RESULTS We included 70 532 influenza cases from seventeen countries. Influenza A and B accounted for a median 76.5% and 23.5% of cases in a season and were the dominant type in 86.8% and 13.2% of seasons. The proportion of influenza A cases that were subtyped was 85.9%, while only 4.4% of influenza B cases were characterized. For most countries, influenza seasonality was similar to the Northern Hemisphere, with a single large peak between January and March; exceptions were the countries in the Arabian Peninsula and Jordan, all of which showed clear secondary peaks, and some countries had an earlier primary peak (in November-December in Bahrain and Qatar). The direction of the timing of influenza activity was east to west and south to north in 2012-2013 and 2015-2016, and west to east in 2014-2015. CONCLUSIONS The epidemiology of influenza is generally uniform in countries of Middle East and North Africa, with influenza B playing an important role in the seasonal disease burden.
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Affiliation(s)
- Saverio Caini
- Netherlands Institute for Health Services Research (NIVEL)UtrechtThe Netherlands
| | | | - Meral A. Ciblak
- Regional Influenza Expert, Africa/Eurasia and Middle East regionSanofi PasteurIstanbulTurkey
| | - John Paget
- Netherlands Institute for Health Services Research (NIVEL)UtrechtThe Netherlands
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Nguenha N, Tivane A, Pale M, Machalele L, Nacoto A, Pires G, Mationane E, Salência J, Gundane F, Muteto D, Chilundo J, Mavale S, Adamo N, Semá-Baltazar C, Augusto O, Gudo E, Mussá T. Clinical and epidemiological characterization of influenza virus infections in children with severe acute respiratory infection in Maputo, Mozambique: Results from the implementation of sentinel surveillance, 2014 - 2016. PLoS One 2018; 13:e0194138. [PMID: 29590162 PMCID: PMC5874022 DOI: 10.1371/journal.pone.0194138] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 02/11/2018] [Indexed: 11/16/2022] Open
Abstract
In Sub-Saharan Africa, where burden, impact, and incidence of acute respiratory infections (ARI) are the highest in the world, conversely, the epidemiology of influenza-associated severe acute respiratory infections (SARI) is incompletely known. The aim of this study was to describe the clinical and epidemiological features of influenza-associated SARI in hospitalized children in Maputo city, Mozambique. Nasopharyngeal and oropharyngeal swabs were collected from children aged 0-14 years old who met the case definition for SARI in two hospitals in Maputo city after their parents or legal representative consented to participate. A structured questionnaire was used to collect clinical and demographic data. Typing and subtyping of influenza were performed by real-time PCR. From January 2014 to December 2016, a total of 2,007 eligible children were recruited, of whom 1,997 (99.5%) were screened for influenza by real-time PCR. The median age of participants was 16.9 months (IQR: 7.0-38.9 months) and 53.9% (1076/1991) were male. A total of 77 were positive for influenza, yielding a frequency of 3.9% (77/1,991), with the highest frequency being reported in the age group 1-5 years old. Cases of influenza peaked twice each year, during which, its frequency reached up to 60%-80%. Among all influenza confirmed cases, 33.7% (26/77), 35.1% (27/77) and 28.6% (22/77) were typed as influenza A/H3N2, A/H1N1pdm09, and B, respectively. This represents the first report of influenza in urban/sub urban setting in Mozambique and the first evidence of distribution of strains of influenza in the country. Our data showed that frequency of influenza was lower than reported in a rural setting in Mozambique and the frequency of seasonal (A/H1N1pdm09) and (A/H3N2) subtypes were similar in children with SARI.
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Affiliation(s)
- Neuza Nguenha
- National Institute of Health, Ministry of Health, Maputo, Mozambique
| | - Almiro Tivane
- National Institute of Health, Ministry of Health, Maputo, Mozambique
| | - Mirela Pale
- National Institute of Health, Ministry of Health, Maputo, Mozambique
| | - Loira Machalele
- National Institute of Health, Ministry of Health, Maputo, Mozambique
| | - Afonso Nacoto
- National Institute of Health, Ministry of Health, Maputo, Mozambique
| | - Germano Pires
- National Institute of Health, Ministry of Health, Maputo, Mozambique
| | - Edirsse Mationane
- National Institute of Health, Ministry of Health, Maputo, Mozambique
| | - Judite Salência
- National Institute of Health, Ministry of Health, Maputo, Mozambique
- Pediatric Departament, Hospital Geral de Mavalane, Maputo, Mozambique
| | - Félix Gundane
- National Institute of Health, Ministry of Health, Maputo, Mozambique
- Pediatric Departament, Hospital Geral de Mavalane, Maputo, Mozambique
| | - Délcio Muteto
- Pediatric Departament, Hospital Central de Maputo, Maputo, Mozambique
| | - Josina Chilundo
- Pediatric Departament, Hospital Central de Maputo, Maputo, Mozambique
| | - Sandra Mavale
- Pediatric Departament, Hospital Central de Maputo, Maputo, Mozambique
| | - Noorbebi Adamo
- National Institute of Health, Ministry of Health, Maputo, Mozambique
| | | | - Orvalho Augusto
- Faculty of Medicine, Eduardo Mondlane University, Maputo, Mozambique
| | - Eduardo Gudo
- National Institute of Health, Ministry of Health, Maputo, Mozambique
| | - Tufária Mussá
- National Institute of Health, Ministry of Health, Maputo, Mozambique
- Faculty of Medicine, Eduardo Mondlane University, Maputo, Mozambique
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Monamele GC, Vernet MA, Nsaibirni RFJ, Bigna JJR, Kenmoe S, Njankouo MR, Njouom R. Associations between meteorological parameters and influenza activity in a subtropical country: Case of five sentinel sites in Yaoundé-Cameroon. PLoS One 2017; 12:e0186914. [PMID: 29088290 PMCID: PMC5663393 DOI: 10.1371/journal.pone.0186914] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 10/10/2017] [Indexed: 12/04/2022] Open
Abstract
Influenza is associated with highly contagious respiratory infections. Previous research has found that influenza transmission is often associated with climate variables especially in temperate regions. This study was performed in order to fill the gap of knowledge regarding the relationship between incidence of influenza and three meteorological parameters (temperature, rainfall and humidity) in a tropical setting. This was a retrospective study performed in Yaoundé-Cameroon from January 2009 to November 2015. Weekly proportions of confirmed influenza cases from five sentinel sites were considered as dependent variables, whereas weekly values of mean temperature, average relative humidity and accumulated rainfall were considered as independent variables. A univariate linear regression model was used in determining associations between influenza activity and weather covariates. A time-series method was used to predict on future values of influenza activity. The data was divided into 2 parts; the first 71 months were used to calibrate the model, and the last 12 months to test for prediction. Overall, there were 1173 confirmed infections with influenza virus. Linear regression analysis showed that there was no statistically significant association observed between influenza activity and weather variables. Very weak relationships (-0.1 < r < 0.1) were observed. Three prediction models were obtained for the different viral types (overall positive, Influenza A and Influenza B). Model 1 (overall influenza) and model 2 (influenza A) fitted well during the estimation period; however, they did not succeed to make good forecasts for predictions. Accumulated rainfall was the only external covariate that enabled good fit of both models. Based on the stationary R2, 29.5% and 41.1% of the variation in the series can be explained by model 1 and 2, respectively. This study laid more emphasis on the fact that influenza in Cameroon is characterized by year-round activity. The meteorological variables selected in this study did not enable good forecast of future influenza activity and certainly acted as proxies to other factors not considered, such as, UV radiation, absolute humidity, air quality and wind.
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Affiliation(s)
- Gwladys C. Monamele
- National Influenza Centre, Centre Pasteur du Cameroun, Yaoundé, Cameroon
- Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | | | | | - Jean Joel R. Bigna
- National Influenza Centre, Centre Pasteur du Cameroun, Yaoundé, Cameroon
| | - Sebastien Kenmoe
- National Influenza Centre, Centre Pasteur du Cameroun, Yaoundé, Cameroon
| | | | - Richard Njouom
- National Influenza Centre, Centre Pasteur du Cameroun, Yaoundé, Cameroon
- * E-mail:
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Ayora-Talavera G, Flores GMZ, Gómez-Carballo J, González-Losa R, Conde-Ferraez L, Puerto-Solís M, López-Martínez I, Díaz-Quiñonez A, Barrera-Badillo G, Acuna-Soto R, Livinski AA, Alonso WJ. Influenza seasonality goes south in the Yucatan Peninsula: The case for a different influenza vaccine calendar in this Mexican region. Vaccine 2017; 35:4738-4744. [PMID: 28755836 DOI: 10.1016/j.vaccine.2017.07.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 06/22/2017] [Accepted: 07/05/2017] [Indexed: 11/29/2022]
Abstract
INTRODUCTION While vaccination may be relatively straightforward for regions with a well-defined winter season, the situation is quite different for tropical regions. Influenza activity in tropical regions might be out of phase with the dynamics predicted for their hemispheric group thereby impacting the effectiveness of the immunization campaign. OBJECTIVE To investigate how the climatic diversity of Mexico hinders its existing influenza immunization strategy and to suggest that the hemispheric vaccine recommendations be tailored to the regional level in order to optimize vaccine effectiveness. METHODS We studied the seasonality of influenza throughoutMexico by modeling virological and mortality data.De-trended time series of each Mexican state were analyzed by Fourier decomposition to describe the amplitude and timing of annual influenza epidemic cycles and to compare with each the timing of the WHO's Northern and Southern Hemispheric vaccination schedule. FINDINGS The timings of the primary (major) peaks of both virological and mortality data for most Mexican states are well aligned with the Northern Hemisphere winter (December-February) and vaccine schedule. However, influenza peaks in September in the three states of the Yucatan Peninsula. Influenza-related mortality also peaks in September in Quintana Roo and Yucatan whereas it peaks in May in Campeche. As the current timing of vaccination in Mexico is between October and November, more than half of the annual influenza cases have already occurred in the Yucatan Peninsula states by the time the Northern Hemispheric vaccine is delivered and administered. CONCLUSION The current Northern Hemispheric influenza calendar adopted for Mexico is not optimal for the Yucatan Peninsula states thereby likely reducing the effectiveness of the immunization of the population. We recommend that Mexico tailor its immunization strategy to better reflect its climatologic and epidemiological diversity and adopt the WHO Southern Hemisphere influenza vaccine and schedule for the Yucatan Peninsula.
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Affiliation(s)
- Guadalupe Ayora-Talavera
- Centro de Investigaciones Regionales Dr. Hideyo Noguchi, Universidad Autónoma de Yucatán, Av. Itzaes #490x59, Centro, C. P. 97000 Merida, Yucatan, Mexico.
| | - Gerardo Montalvo-Zurbia Flores
- Centro de Investigaciones Regionales Dr. Hideyo Noguchi, Universidad Autónoma de Yucatán, Av. Itzaes #490x59, Centro, C. P. 97000 Merida, Yucatan, Mexico.
| | - Jesus Gómez-Carballo
- Centro de Investigaciones Regionales Dr. Hideyo Noguchi, Universidad Autónoma de Yucatán, Av. Itzaes #490x59, Centro, C. P. 97000 Merida, Yucatan, Mexico.
| | - Refugio González-Losa
- Centro de Investigaciones Regionales Dr. Hideyo Noguchi, Universidad Autónoma de Yucatán, Av. Itzaes #490x59, Centro, C. P. 97000 Merida, Yucatan, Mexico.
| | - Laura Conde-Ferraez
- Centro de Investigaciones Regionales Dr. Hideyo Noguchi, Universidad Autónoma de Yucatán, Av. Itzaes #490x59, Centro, C. P. 97000 Merida, Yucatan, Mexico.
| | - Marylin Puerto-Solís
- Centro de Investigaciones Regionales Dr. Hideyo Noguchi, Universidad Autónoma de Yucatán, Av. Itzaes #490x59, Centro, C. P. 97000 Merida, Yucatan, Mexico.
| | - Irma López-Martínez
- Instituto de Diagnóstico y Referencia Epidemiológicos "Dr. Manuel Martínez Báez" (InDRE), Secretaría de Salud, Francisco de P. Miranda 177, Lomas de Plateros, 01480 Álvaro Obregón, Mexico City, Mexico.
| | - Alberto Díaz-Quiñonez
- Instituto de Diagnóstico y Referencia Epidemiológicos "Dr. Manuel Martínez Báez" (InDRE), Secretaría de Salud, Francisco de P. Miranda 177, Lomas de Plateros, 01480 Álvaro Obregón, Mexico City, Mexico.
| | - Gisela Barrera-Badillo
- Instituto de Diagnóstico y Referencia Epidemiológicos "Dr. Manuel Martínez Báez" (InDRE), Secretaría de Salud, Francisco de P. Miranda 177, Lomas de Plateros, 01480 Álvaro Obregón, Mexico City, Mexico.
| | - Rodolfo Acuna-Soto
- Departamento de Microbiologia y Parasitologia, Facultad de Medicina, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Avenida Insurgentes Sur 3000, Del. Coyoacán, C.P. 04510 Ciudad de México, Mexico.
| | - Alicia A Livinski
- National Institute of Health Library, Division of Library Services, Office of Research Services, 10 Center Drive, Bethesda, MD 20892, USA.
| | - Wladimir J Alonso
- Fogarty International Center, National Institutes of Health, 16 Center Drive, Bethesda, MD 20892, USA.
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Tamerius J, Ojeda S, Uejio CK, Shaman J, Lopez B, Sanchez N, Gordon A. Influenza transmission during extreme indoor conditions in a low-resource tropical setting. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2017; 61:613-622. [PMID: 27562031 DOI: 10.1007/s00484-016-1238-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 08/10/2016] [Accepted: 08/15/2016] [Indexed: 06/06/2023]
Abstract
Influenza transmission occurs throughout the planet across wide-ranging environmental conditions. However, our understanding of the environmental factors mediating transmission is evaluated using outdoor environmental measurements, which may not be representative of the indoor conditions where influenza is transmitted. In this study, we examined the relationship between indoor environment and influenza transmission in a low-resource tropical population. We used a case-based ascertainment design to enroll 34 households with a suspected influenza case and then monitored households for influenza, while recording indoor temperature and humidity data in each household. We show that the indoor environment is not commensurate with outdoor conditions and that the relationship between indoor and outdoor conditions varies significantly across homes. We also show evidence of influenza transmission in extreme indoor environments. Specifically, our data suggests that indoor environments averaged 29 °C, 18 g/kg specific humidity, and 68 % relative humidity across 15 transmission events observed. These indoor settings also exhibited significant temporal variability with temperatures as high as 39 °C and specific and relative humidity increasing to 22 g/kg and 85 %, respectively, during some transmission events. However, we were unable to detect differences in the transmission efficiency by indoor temperature or humidity conditions. Overall, these results indicate that laboratory studies investigating influenza transmission and virus survival should increase the range of environmental conditions that they assess and that observational studies investigating the relationship between environment and influenza activity should use caution using outdoor environmental measurements since they can be imprecise estimates of the conditions that mediate transmission indoors.
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Affiliation(s)
- James Tamerius
- Department of Geographical and Sustainability Sciences, University of Iowa, 316 Jessup Hall, Iowa City, IA, 52242, USA.
| | - Sergio Ojeda
- Sustainable Sciences Institute, Managua, Nicaragua
| | - Christopher K Uejio
- Department of Geography and Program in Public Health, Florida State University, Tallahassee, FL, USA
- Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, MI, USA
| | - Jeffrey Shaman
- Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY, USA
| | - Brenda Lopez
- Sustainable Sciences Institute, Managua, Nicaragua
| | - Nery Sanchez
- Sustainable Sciences Institute, Managua, Nicaragua
| | - Aubree Gordon
- Department of Geography and Program in Public Health, Florida State University, Tallahassee, FL, USA
- Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, MI, USA
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Hogan AB, Anderssen RS, Davis S, Moore HC, Lim FJ, Fathima P, Glass K. Time series analysis of RSV and bronchiolitis seasonality in temperate and tropical Western Australia. Epidemics 2016; 16:49-55. [PMID: 27294794 DOI: 10.1016/j.epidem.2016.05.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 05/08/2016] [Accepted: 05/09/2016] [Indexed: 12/26/2022] Open
Abstract
Respiratory syncytial virus (RSV) causes respiratory illness in young children and is most commonly associated with bronchiolitis. RSV typically occurs as annual or biennial winter epidemics in temperate regions, with less pronounced seasonality in the tropics. We sought to characterise and compare the seasonality of RSV and bronchiolitis in temperate and tropical Western Australia. We examined over 13 years of RSV laboratory identifications and bronchiolitis hospitalisations in children, using an extensive linked dataset from Western Australia. We applied mathematical time series analyses to identify the dominant seasonal cycle, and changes in epidemic size and timing over this period. Both the RSV and bronchiolitis data showed clear winter epidemic peaks in July or August in the southern Western Australia regions, but less identifiable seasonality in the northern regions. Use of complex demodulation proved very effective at comparing disease epidemics. The timing of RSV and bronchiolitis epidemics coincided well, but the size of the epidemics differed, with more consistent peak sizes for bronchiolitis than for RSV. Our results show that bronchiolitis hospitalisations are a reasonable proxy for the timing of RSV detections, but may not fully capture the magnitude of RSV epidemics.
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Affiliation(s)
- Alexandra B Hogan
- National Centre for Epidemiology and Population Health, Research School of Population Health, The Australian National University, Australia.
| | - Robert S Anderssen
- CSIRO Data61; Mathematical Sciences Institute, The Australian National University; Mathematics and Statistics, La Trobe University, Australia
| | - Stephanie Davis
- National Centre for Epidemiology and Population Health, Research School of Population Health, The Australian National University, Australia
| | - Hannah C Moore
- Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, The University of Western Australia, Australia
| | - Faye J Lim
- Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, The University of Western Australia, Australia
| | - Parveen Fathima
- Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, The University of Western Australia, Australia
| | - Kathryn Glass
- National Centre for Epidemiology and Population Health, Research School of Population Health, The Australian National University, Australia
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Temporal Patterns of Influenza A and B in Tropical and Temperate Countries: What Are the Lessons for Influenza Vaccination? PLoS One 2016; 11:e0152310. [PMID: 27031105 PMCID: PMC4816507 DOI: 10.1371/journal.pone.0152310] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 03/11/2016] [Indexed: 12/28/2022] Open
Abstract
Introduction Determining the optimal time to vaccinate is important for influenza vaccination programmes. Here, we assessed the temporal characteristics of influenza epidemics in the Northern and Southern hemispheres and in the tropics, and discuss their implications for vaccination programmes. Methods This was a retrospective analysis of surveillance data between 2000 and 2014 from the Global Influenza B Study database. The seasonal peak of influenza was defined as the week with the most reported cases (overall, A, and B) in the season. The duration of seasonal activity was assessed using the maximum proportion of influenza cases during three consecutive months and the minimum number of months with ≥80% of cases in the season. We also assessed whether co-circulation of A and B virus types affected the duration of influenza epidemics. Results 212 influenza seasons and 571,907 cases were included from 30 countries. In tropical countries, the seasonal influenza activity lasted longer and the peaks of influenza A and B coincided less frequently than in temperate countries. Temporal characteristics of influenza epidemics were heterogeneous in the tropics, with distinct seasonal epidemics observed only in some countries. Seasons with co-circulation of influenza A and B were longer than influenza A seasons, especially in the tropics. Discussion Our findings show that influenza seasonality is less well defined in the tropics than in temperate regions. This has important implications for vaccination programmes in these countries. High-quality influenza surveillance systems are needed in the tropics to enable decisions about when to vaccinate.
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Alonso WJ, Yu C, Viboud C, Richard SA, Schuck-Paim C, Simonsen L, Mello WA, Miller MA. A global map of hemispheric influenza vaccine recommendations based on local patterns of viral circulation. Sci Rep 2015; 5:17214. [PMID: 26621769 PMCID: PMC4664865 DOI: 10.1038/srep17214] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 10/27/2015] [Indexed: 11/28/2022] Open
Abstract
Both the Northern and the Southern Hemisphere annual WHO influenza vaccine recommendations are designed to ensure vaccine delivery before the winter-time peak of viral circulation in each hemisphere. However, influenza seasonal patterns are highly diverse in tropical countries and may be out of phase with the WHO recommendations for their respective hemisphere. We modelled the peak timing of influenza activity for 125 countries using laboratory-based surveillance data from the WHO's FLUNET database and compared it with the influenza hemispheric recommendations in place. Influenza vaccine recommendations for respectively 25% and 39% of the Northern and Southern Hemisphere countries were out of phase with peak influenza circulation in their corresponding hemisphere (62% and 53%, respectively, when the analysis was limited to the 52 countries in the tropical belt). These results indicate that routine influenza immunization efforts should be closely tailored to local patterns of viral circulation, rather than a country's hemispheric position.
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Affiliation(s)
- Wladimir J. Alonso
- National Institutes of Health, Fogarty International Center, Bethesda, MD, 20892, USA
| | - Christine Yu
- George Washington University, Milken Institute School of Public Health, Washington, DC 20052, USA
| | - Cecile Viboud
- National Institutes of Health, Fogarty International Center, Bethesda, MD, 20892, USA
| | - Stephanie A. Richard
- National Institutes of Health, Fogarty International Center, Bethesda, MD, 20892, USA
| | | | - Lone Simonsen
- George Washington University, Milken Institute School of Public Health, Washington, DC 20052, USA
| | - Wyller A. Mello
- Evandro Chagas Institute, WHO Global Influenza Surveillance Network, Para, Brazil
| | - Mark A. Miller
- National Institutes of Health, Fogarty International Center, Bethesda, MD, 20892, USA
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