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Ruttoh VK, Symekher SL, Majanja JM, Opanda SM, Chitechi EW, Wadegu M, Tonui R, Rotich PK, Nyandwaro TT, Mwangi AW, Mwangi IN, Oira RM, Musimbi AG, Nzou SM. Tracking severe acute respiratory syndrome coronavirus 2 transmission and co-infection with other acute respiratory pathogens using a sentinel surveillance system in Rift Valley, Kenya. Influenza Other Respir Viruses 2023; 17:e13227. [PMID: 38019696 PMCID: PMC10686236 DOI: 10.1111/irv.13227] [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: 05/29/2023] [Revised: 10/29/2023] [Accepted: 11/05/2023] [Indexed: 12/01/2023] Open
Abstract
BACKGROUND The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been the most significant public health challenge in over a century. SARS-CoV-2 has infected over 765 million people worldwide, resulting in over 6.9 million deaths. This study aimed to detect community transmission of SARS-CoV-2 and monitor the co-circulation of SARS-CoV-2 with other acute respiratory pathogens in Rift Valley, Kenya. METHODS We conducted a cross-sectional active sentinel surveillance for the SARS-CoV-2 virus among patients with acute respiratory infections at four sites in Rift Valley from January 2022 to December 2022. One thousand two hundred seventy-one patients aged between 3 years and 98 years presenting with influenza-like illness (ILI) were recruited into the study. Nasopharyngeal swab specimens from all study participants were screened using a reverse transcription-quantitative polymerase chain reaction (RT-qPCR) for SARS-CoV-2, influenza A, influenza B and respiratory syncytial virus (RSV). RESULTS The samples that tested positive for influenza A (n = 73) and RSV (n = 12) were subtyped, while SARS-CoV-2 (n = 177) positive samples were further screened for 12 viral and seven bacterial respiratory pathogens. We had a prevalence of 13.9% for SARS-CoV-2, 5.7% for influenza A, 2% for influenza B and 1% for RSV. Influenza A-H1pdm09 and RSV B were the most dominant circulating subtypes of influenza A and RSV, respectively. The most common co-infecting pathogens were Streptococcus pneumoniae (n = 29) and Haemophilus influenzae (n = 19), accounting for 16.4% and 10.7% of all the SARS-CoV-2 positive samples. CONCLUSIONS Augmenting syndromic testing in acute respiratory infections (ARIs) surveillance is crucial to inform evidence-based clinical and public health interventions.
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Affiliation(s)
| | | | | | | | | | - Meshack Wadegu
- Centre for Virus ResearchKenya Medical Research InstituteNairobiKenya
| | - Ronald Tonui
- Department of Molecular Biology and BiotechnologyPan African University Institute of Basic Sciences Technology and InnovationNairobiKenya
| | | | | | - Anne Wanjiru Mwangi
- Centre for Microbiology ResearchKenya Medical Research InstituteNairobiKenya
| | - Ibrahim Ndungu Mwangi
- Centre for Biotechnology Research and DevelopmentKenya Medical Research InstituteNairobiKenya
| | | | | | - Samson Muuo Nzou
- Centre for Microbiology ResearchKenya Medical Research InstituteNairobiKenya
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Waterlow NR, Radhakrishnan S, Dawa J, van Leeuwen E, Procter SR, Lambach P, Bresee J, Mazur M, Eggo RM, Jit M. Potential health and economic impact of paediatric vaccination using next-generation influenza vaccines in Kenya: a modelling study. BMC Med 2023; 21:106. [PMID: 36949456 PMCID: PMC10032252 DOI: 10.1186/s12916-023-02830-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 01/30/2023] [Indexed: 03/24/2023] Open
Abstract
BACKGROUND Influenza is a major year-round cause of respiratory illness in Kenya, particularly in children under 5. Current influenza vaccines result in short-term, strain-specific immunity and were found in a previous study not to be cost-effective in Kenya. However, next-generation vaccines are in development that may have a greater impact and cost-effectiveness profile. METHODS We expanded a model previously used to evaluate the cost-effectiveness of seasonal influenza vaccines in Kenya to include next-generation vaccines by allowing for enhanced vaccine characteristics and multi-annual immunity. We specifically examined vaccinating children under 5 years of age with improved vaccines, evaluating vaccines with combinations of increased vaccine effectiveness, cross-protection between strains (breadth) and duration of immunity. We evaluated cost-effectiveness using incremental cost-effectiveness ratios (ICERs) and incremental net monetary benefits (INMBs) for a range of values for the willingness-to-pay (WTP) per DALY averted. Finally, we estimated threshold per-dose vaccine prices at which vaccination becomes cost-effective. RESULTS Next-generation vaccines can be cost-effective, dependent on the vaccine characteristics and assumed WTP thresholds. Universal vaccines (assumed to provide long-term and broad immunity) are most cost-effective in Kenya across three of four WTP thresholds evaluated, with the lowest median value of ICER per DALY averted ($263, 95% Credible Interval (CrI): $ - 1698, $1061) and the highest median INMBs. At a WTP of $623, universal vaccines are cost-effective at or below a median price of $5.16 per dose (95% CrI: $0.94, $18.57). We also show that the assumed mechanism underlying infection-derived immunity strongly impacts vaccine outcomes. CONCLUSIONS This evaluation provides evidence for country-level decision makers about future next-generation vaccine introduction, as well as global research funders about the potential market for these vaccines. Next-generation vaccines may offer a cost-effective intervention to reduce influenza burden in low-income countries with year-round seasonality like Kenya.
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Affiliation(s)
- Naomi R Waterlow
- Centre for Mathematical Modeling of Infectious Disease, London School of Hygiene and Tropical Medicine, London, WC14 7HT, UK.
| | - Sreejith Radhakrishnan
- Centre for Mathematical Modeling of Infectious Disease, London School of Hygiene and Tropical Medicine, London, WC14 7HT, UK
- School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, G61 1QH, UK
| | - Jeanette Dawa
- Center for Epidemiological Modelling and Analysis, University of Nairobi, Nairobi, Kenya
- Washington State University - Global Health Kenya, Nairobi, Kenya
| | - Edwin van Leeuwen
- Centre for Mathematical Modeling of Infectious Disease, London School of Hygiene and Tropical Medicine, London, WC14 7HT, UK
- Statistics, Modelling and Economics Department, UK Health Security Agency, London, NW9 5EQ, UK
| | - Simon R Procter
- Centre for Mathematical Modeling of Infectious Disease, London School of Hygiene and Tropical Medicine, London, WC14 7HT, UK
| | - Philipp Lambach
- Immunization Vaccines and Biologicals Department, World Health Organization, Geneva, Switzerland
| | | | | | - Rosalind M Eggo
- Centre for Mathematical Modeling of Infectious Disease, London School of Hygiene and Tropical Medicine, London, WC14 7HT, UK
| | - Mark Jit
- Centre for Mathematical Modeling of Infectious Disease, London School of Hygiene and Tropical Medicine, London, WC14 7HT, UK
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Apopo AA, Kariithi HM, Ateya LO, Binepal YS, Sirya JH, Dulu TD, Welch CN, Hernandez SM, Afonso CL. A retrospective study of Newcastle disease in Kenya. Trop Anim Health Prod 2019; 52:699-710. [PMID: 31501991 PMCID: PMC7039849 DOI: 10.1007/s11250-019-02059-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 08/29/2019] [Indexed: 11/16/2022]
Abstract
Newcastle disease (ND) is a major constraint to Kenya’s poultry production, which is comprised of approximately 80% indigenous chickens (ICs; caged and free-range system) and 20% exotic chickens (intensive system). This study analyzed cases reported as suspected ND in Kenya between 2005 and 2015. Of the suspected 332 ND reported cases from the three production systems in 27 locations within six Kenyan Agro-Ecological Zones (AEZs), 140 diagnosed as infected with avian orthoavulavirus 1 (AOaV-1; formerly Newcastle disease virus) were present in every year in all AEZs. The numbers of AOaV-1-positive cases differed significantly (p < 0.05) between the production systems across the years depending on the season, climate, and location. In the free-range system, both ambient temperatures and season associated significantly (p = 0.001 and 0.02, respectively) with the number of cases, while in the intensive and caged systems, the positive cases correlated significantly with season and relative humidity, respectively (p = 0.05). Regardless of the production systems, the numbers of clinically sick birds positively correlated with the ambient temperatures (r = 0.6; p < 0.05). Failure to detect AOaV-1 in 58% of the ND cases reported, and mortalities exceeding the observed numbers of clinically sick birds suggest deficiencies in the current ND reporting and diagnostic system. Intensive farmers were the slowest in reporting the cases and diagnostic deficiencies were most evident by failure to test the exposure of ICs to natural infection with AOaV-1 and for the AOaV-1-negative cases lack of testing for other pathogens and/or AOaV-1 variants. This study indicates a need for improved surveillance and diagnostics in Kenyan domestic poultry.
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Affiliation(s)
- Auleria A Apopo
- Directorate of Veterinary Services, State Department for Livestock, Ministry of Agriculture, Livestock, Fisheries and Irrigation, Private Bag-00625, Nairobi, Kenya
| | - Henry M Kariithi
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, P.O Box 57811, Kaptagat Road, Loresho, Nairobi, 00200, Kenya. .,Exotic and Emerging Avian Viral Diseases Research Unit, Southeast Poultry Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture, US National Poultry Research Center, 934 College Station Road, Athens, GA, 30605, USA.
| | - Leonard O Ateya
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, P.O Box 57811, Kaptagat Road, Loresho, Nairobi, 00200, Kenya
| | - Yatinder S Binepal
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, P.O Box 57811, Kaptagat Road, Loresho, Nairobi, 00200, Kenya
| | - Jane H Sirya
- Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology, P.O. Box 62000, Nairobi, 00200, Kenya
| | - Thomas D Dulu
- Directorate of Veterinary Services, State Department for Livestock, Ministry of Agriculture, Livestock, Fisheries and Irrigation, Private Bag-00625, Nairobi, Kenya
| | - Catharine N Welch
- Warnell School of Forestry and Natural Resources and The Southeastern Cooperative Wildlife Disease Study at the College of Veterinary Medicine, University of Georgia, Athens, GA, 30602, USA
| | - Sonia M Hernandez
- Warnell School of Forestry and Natural Resources and The Southeastern Cooperative Wildlife Disease Study at the College of Veterinary Medicine, University of Georgia, Athens, GA, 30602, USA
| | - Claudio L Afonso
- Exotic and Emerging Avian Viral Diseases Research Unit, Southeast Poultry Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture, US National Poultry Research Center, 934 College Station Road, Athens, GA, 30605, USA
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Kanyiri CW, Mark K, Luboobi L. Mathematical Analysis of Influenza A Dynamics in the Emergence of Drug Resistance. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2018; 2018:2434560. [PMID: 30245737 PMCID: PMC6136569 DOI: 10.1155/2018/2434560] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Revised: 06/12/2018] [Accepted: 07/12/2018] [Indexed: 01/08/2023]
Abstract
Every year, influenza causes high morbidity and mortality especially among the immunocompromised persons worldwide. The emergence of drug resistance has been a major challenge in curbing the spread of influenza. In this paper, a mathematical model is formulated and used to analyze the transmission dynamics of influenza A virus having incorporated the aspect of drug resistance. The qualitative analysis of the model is given in terms of the control reproduction number, Rc. The model equilibria are computed and stability analysis carried out. The model is found to exhibit backward bifurcation prompting the need to lower Rc to a critical value Rc∗ for effective disease control. Sensitivity analysis results reveal that vaccine efficacy is the parameter with the most control over the spread of influenza. Numerical simulations reveal that despite vaccination reducing the reproduction number below unity, influenza still persists in the population. Hence, it is essential, in addition to vaccination, to apply other strategies to curb the spread of influenza.
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Affiliation(s)
- Caroline W. Kanyiri
- Department of Mathematics, Pan African University Institute of Basic Sciences, Technology and Innovation, P.O. Box 62000-00200, Nairobi, Kenya
| | - Kimathi Mark
- Department of Mathematics, Machakos University, P.O. Box 139-90100, Machakos, Kenya
| | - Livingstone Luboobi
- Institute of Mathematical Sciences, Strathmore University, P.O. Box 59857-00200, Nairobi, Kenya
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Talla Nzussouo N, Duque J, Adedeji AA, Coulibaly D, Sow S, Tarnagda Z, Maman I, Lagare A, Makaya S, Elkory MB, Kadjo Adje H, Shilo PA, Tamboura B, Cisse A, Badziklou K, Maïnassara HB, Bara AO, Keita AM, Williams T, Moen A, Widdowson MA, McMorrow M. Epidemiology of influenza in West Africa after the 2009 influenza A(H1N1) pandemic, 2010-2012. BMC Infect Dis 2017; 17:745. [PMID: 29202715 PMCID: PMC5716025 DOI: 10.1186/s12879-017-2839-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 11/16/2017] [Indexed: 01/20/2023] Open
Abstract
Background Over the last decade, capacity for influenza surveillance and research in West Africa has strengthened. Data from these surveillance systems showed influenza A(H1N1)pdm09 circulated in West Africa later than in other regions of the continent. Methods We contacted 11 West African countries to collect information about their influenza surveillance systems (number of sites, type of surveillance, sampling strategy, populations sampled, case definitions used, number of specimens collected and number of specimens positive for influenza viruses) for the time period January 2010 through December 2012. Results Of the 11 countries contacted, 8 responded: Burkina Faso, Cote d’Ivoire, Mali, Mauritania, Niger, Nigeria, Sierra Leone and Togo. Countries used standard World Health Organization (WHO) case definitions for influenza-like illness (ILI) and severe acute respiratory illness (SARI) or slight variations thereof. There were 70 surveillance sites: 26 SARI and 44 ILI. Seven countries conducted SARI surveillance and collected 3114 specimens of which 209 (7%) were positive for influenza viruses. Among influenza-positive SARI patients, 132 (63%) were influenza A [68 influenza A(H1N1)pdm09, 64 influenza A(H3N2)] and 77 (37%) were influenza B. All eight countries conducted ILI surveillance and collected 20,375 specimens, of which 2278 (11%) were positive for influenza viruses. Among influenza-positive ILI patients, 1431 (63%) were influenza A [820 influenza A(H1N1)pdm09, 611 influenza A(H3N2)] and 847 (37%) were influenza B. A majority of SARI and ILI case-patients who tested positive for influenza (72% SARI and 59% ILI) were children aged 0–4 years, as were a majority of those enrolled in surveillance. The seasonality of influenza and the predominant influenza type or subtype varied by country and year. Conclusions Influenza A(H1N1)pdm09 continued to circulate in West Africa along with influenza A(H3N2) and influenza B during 2010–2012. Although ILI surveillance systems produced a robust number of samples during the study period, more could be done to strengthen surveillance among hospitalized SARI case-patients. Surveillance systems captured young children but lacked data on adults and the elderly. More data on risk groups for severe influenza in West Africa are needed to help shape influenza prevention and clinical management policies and guidelines. Electronic supplementary material The online version of this article (10.1186/s12879-017-2839-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ndahwouh Talla Nzussouo
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA. .,CTS Global Inc., California, El Segundo, USA. .,Noguchi Memorial Institute for Medical Research, P.O. Box LG 481, Legon, Accra, Ghana.
| | - Jazmin Duque
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA.,Battelle Atlanta, Atlanta, GA, USA
| | - Adebayo Abel Adedeji
- National Influenza Reference Laboratory, Federal Ministry of Health, Abuja, Nigeria
| | - Daouda Coulibaly
- Institut National d'Hygiene Publique (INHP), Abidjan, Côte d'Ivoire
| | - Samba Sow
- Centre National d'Appui à la Lutte Contre la Maladie (CNAM), Centre pour le Développement des Vaccins du Mali (CVD), Bamako, Mali
| | - Zekiba Tarnagda
- Institut de Recherche en Sciences de Santé (IRSS), Bobo-Dioulasso, Burkina Faso
| | | | - Adamou Lagare
- Centre de Recherche Médicale et Sanitaire (CERMES), Niamey, Niger
| | - Sonia Makaya
- Influenza National Reference Laboratory Lakka, Freetown, Sierra Leone
| | | | | | - Paul Alhassan Shilo
- National Influenza Reference Laboratory, Federal Ministry of Health, Abuja, Nigeria
| | - Boubou Tamboura
- Centre National d'Appui à la Lutte Contre la Maladie (CNAM), Centre pour le Développement des Vaccins du Mali (CVD), Bamako, Mali
| | - Assana Cisse
- Institut de Recherche en Sciences de Santé (IRSS), Bobo-Dioulasso, Burkina Faso
| | | | | | - Ahmed Ould Bara
- Institut National Recherche en Sante Publique (INRSP), Nouakchott, Mauritanie
| | - Adama Mamby Keita
- Centre National d'Appui à la Lutte Contre la Maladie (CNAM), Centre pour le Développement des Vaccins du Mali (CVD), Bamako, Mali
| | - Thelma Williams
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Ann Moen
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Marc-Alain Widdowson
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Meredith McMorrow
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA.,U.S. Public Health Service, Rockville, MD, USA
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Epidemiology and Surveillance of Influenza Viruses in Uganda between 2008 and 2014. PLoS One 2016; 11:e0164861. [PMID: 27755572 PMCID: PMC5068740 DOI: 10.1371/journal.pone.0164861] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 10/03/2016] [Indexed: 02/04/2023] Open
Abstract
INTRODUCTION Influenza surveillance was conducted in Uganda from October 2008 to December 2014 to identify and understand the epidemiology of circulating influenza strains in out-patient clinic attendees with influenza-like illness and inform control strategies. METHODOLOGY Surveillance was conducted at five hospital-based sentinel sites. Nasopharyngeal and/or oropharyngeal samples, epidemiological and clinical data were collected from enrolled patients. Real-time reverse transcription polymerase chain reaction (RT-PCR) was performed to identify and subtype influenza strains. Data were double-entered into an Epi Info 3.5.3 database and exported to STATA 13.0 software for analysis. RESULTS Of the 6,628 patient samples tested, influenza virus infection was detected in 10.4% (n = 687/6,628) of the specimens. Several trends were observed: influenza circulates throughout the year with two peaks; the major one from September to November and a minor one from March to June. The predominant strains of influenza varied over the years: Seasonal Influenza A(H3) virus was predominant from 2008 to 2009 and from 2012 to 2014; Influenza A(H1N1)pdm01 was dominant in 2010; and Influenza B virus was dominant in 2011. The peaks generally coincided with times of higher humidity, lower temperature, and higher rainfall. CONCLUSION Influenza circulated throughout the year in Uganda with two major peaks of outbreaks with similar strains circulating elsewhere in the region. Data on the circulating strains of influenza and its patterns of occurrence provided critical insights to informing the design and timing of influenza vaccines for influenza prevention in tropical regions of sub-Saharan Africa.
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Hirve S, Newman LP, Paget J, Azziz-Baumgartner E, Fitzner J, Bhat N, Vandemaele K, Zhang W. Influenza Seasonality in the Tropics and Subtropics - When to Vaccinate? PLoS One 2016; 11:e0153003. [PMID: 27119988 PMCID: PMC4847850 DOI: 10.1371/journal.pone.0153003] [Citation(s) in RCA: 125] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Accepted: 03/22/2016] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND The timing of the biannual WHO influenza vaccine composition selection and production cycle has been historically directed to the influenza seasonality patterns in the temperate regions of the northern and southern hemispheres. Influenza activity, however, is poorly understood in the tropics with multiple peaks and identifiable year-round activity. The evidence-base needed to take informed decisions on vaccination timing and vaccine formulation is often lacking for the tropics and subtropics. This paper aims to assess influenza seasonality in the tropics and subtropics. It explores geographical grouping of countries into vaccination zones based on optimal timing of influenza vaccination. METHODS Influenza seasonality was assessed by different analytic approaches (weekly proportion of positive cases, time series analysis, etc.) using FluNet and national surveillance data. In case of discordance in the seasonality assessment, consensus was built through discussions with in-country experts. Countries with similar onset periods of their primary influenza season were grouped into geographical zones. RESULTS The number and period of peak activity was ascertained for 70 of the 138 countries in the tropics and subtropics. Thirty-seven countries had one and seventeen countries had two distinct peaks. Countries near the equator had secondary peaks or even identifiable year-round activity. The main influenza season in most of South America and Asia started between April and June. The start of the main season varied widely in Africa (October and December in northern Africa, April and June in Southern Africa and a mixed pattern in tropical Africa). Eight "influenza vaccination zones" (two each in America and Asia, and four in Africa and Middle East) were defined with recommendations for vaccination timing and vaccine formulation. The main limitation of our study is that FluNet and national surveillance data may lack the granularity to detect sub-national variability in seasonality patterns. CONCLUSION Distinct influenza seasonality patterns, though complex, could be ascertained for most countries in the tropics and subtropics using national surveillance data. It may be possible to group countries into zones based on similar recommendations for vaccine timing and formulation.
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Affiliation(s)
| | - Laura P. Newman
- University of Washington, Seattle, Washington, United States of America
| | - John Paget
- Netherlands Institute for Health Services Research, Utrecht, The Netherlands
| | | | - Julia Fitzner
- Global Influenza Program, World Health Organization, Geneva, Switzerland
| | - Niranjan Bhat
- Program for Appropriate Technology, Seattle, Washington, United States of America
| | | | - Wenqing Zhang
- Global Influenza Program, World Health Organization, Geneva, Switzerland
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Considerations of strategies to provide influenza vaccine year round. Vaccine 2015; 33:6493-8. [PMID: 26319745 PMCID: PMC8218336 DOI: 10.1016/j.vaccine.2015.08.037] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Revised: 07/27/2015] [Accepted: 08/11/2015] [Indexed: 11/20/2022]
Abstract
There is potential for influenza vaccine programmes to make a substantial impact on severe disease in low-resource settings, however questions around vaccine composition and programmatic issues will require special attention. Some countries may benefit from immunization programmes that provide year-round supply of vaccine; however the best way to ensure adequate vaccine supply has yet to be determined. In this report, we discuss vaccine composition, availability, and programmatic issues that must be considered when developing year-round influenza immunization programmes. We then explore how these considerations have influenced immunization practices in the Latin American region as a case study. We identify three different approaches to achieve year-round supply: (1) alternating between Northern Hemisphere and Southern Hemisphere formulations, (2) extending the expiration date to permit extended use of a single hemisphere formulation, and (3) local vaccine manufacture with production timelines that align with local epidemiology. Each approach has its challenges and opportunities. The growing data suggesting high influenza disease burden in low resource countries underscores the compelling public health need to determine the best strategies for vaccine delivery.
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Burmaa A, Kamigaki T, Darmaa B, Nymadawa P, Oshitani H. Epidemiology and impact of influenza in Mongolia, 2007-2012. Influenza Other Respir Viruses 2014; 8:530-7. [PMID: 25043147 PMCID: PMC4181816 DOI: 10.1111/irv.12268] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/11/2014] [Indexed: 11/28/2022] Open
Abstract
Background Mongolia's Health Service began to conduct surveillance for influenza in the 1970s. This surveillance has become more comprehensive over time and now includes 155 sentinel sites in Mongolia. In this study, we analyzed the epidemiological characteristics and impact of influenza using data from influenza surveillance in Mongolia. Materials and methods The data were collected by the National Influenza Center, Mongolia (NIC). Incidence rates of influenza-like illness (ILI) and severe acute respiratory infections (sARI) were calculated as the proportion of the number of ILI and sARI cases to the total population in the studied areas. Nasopharyngeal samples were collected and tested using real-time reverse transcription polymerase chain reaction [(rt)-RT-PCR]. Selected samples negative for influenza were tested for other respiratory pathogens by multiplex rt-RT-PCR. Results Averages of 14·0 ILI and 0·8 sARI episodes per 100 population per year were observed during the five influenza seasons. The highest incidences of influenza associated with ILI and sARI were observed among children 0–4 years old. The number of ILI cases showed a clear seasonality, generally peaking between December and February. In contrast, sARI incidence peaked twice during each season. Influenza B was most prevalent during 2007–2008 and 2011–2012, influenza A (H3N2) during 2010–2011, seasonal A (H1N1) during 2008–2009, and A (H1N1) pdm09 during 2009–2010. Conclusions Additional data on the epidemiology and impact of influenza including socioeconomic impact and vaccine effectiveness are required to develop a national influenza control policy, including a vaccination strategy. Our results provide useful data for developing such a policy.
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Affiliation(s)
- Alexanderyn Burmaa
- National Influenza Center, National Center of Communicable Diseases, Ulaanbaatar, Mongolia
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