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Forbi JC, Musa MS, Salawu M, Idris JM, Ba’aba AI, Higgins J, Musa AI, Bashir B, Shettima A, Njeakor N, Uzoma I, Mshelia H, Nganda GW, Mohammed KI, Bomoi IM, Chiroma U, Kovacs SD, Biya O, Waziri NE, Aina M, Adamu US, Shuaib F, Bolu O, Franka R, Wiesen E. Historical reconstruction of inaccessibility status in Local Government Areas (LGAs) of Borno and Yobe States, Nigeria, 2010-2020. Pan Afr Med J 2023; 45:7. [PMID: 38370102 PMCID: PMC10874094 DOI: 10.11604/pamj.supp.2023.45.2.39332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 06/09/2023] [Indexed: 02/20/2024] Open
Abstract
Introduction ultimately detected in 2016, wild poliovirus (WPV) transmission continued undetected after 2011 in Northeast Nigeria Borno and Yobe States in security-compromised areas, inaccessible due to armed insurgency. Varying inaccessibility prevented children aged <5 years in these areas from polio vaccination interventions and surveillance, while massive population displacements occurred. We examined progress in access over time to provide data supporting a very low probability of undetected WPV circulation within remaining trapped populations after 2016. Methods to assess the extent of inaccessibility in security-compromised areas, we obtained empirical historical data in 2020 on a quarterly and annual basis from relevant polio eradication staff for the period 2010-2020. The extent of access to areas for immunization by recall was compared to geospatial data from vaccinator tracking. Population estimates over time in security-compromised areas were extracted from satellite imagery. We compared the historical access data from staff with tracking and population esimates. Results access varied during 2010-2020, with inaccessibility peaking during 2014-2016. We observed concurrent patterns between historical recalled data on inaccessibility and contemporaneous satellite imagery on population displacements, which increased confidence in the quality of recalled data. Conclusion staff-recalled access was consistent with vaccinator tracking and satellite imagery of population displacments. Despite variability in inaccessibility over time, innovative immunization initiatives were implemented as access allowed and surveillance initiatives were initiated to search for poliovirus transmission. Along with escape and liberation of residents by the military in some geographic areas, these initiatives resulted in a massive reduction in the size of the unvaccinated population remaining resident.
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Affiliation(s)
- Joseph Che Forbi
- Polio Elimination Branch, US Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | | | - Musa Salawu
- Bill and Melinda Gates Foundation, Abuja, Nigeria
| | | | | | - Jeff Higgins
- Geospatial Research, Analysis and Services Program, Agency for Toxic Substances and Disease Registry, US Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | | | | | | | | | | | - Hyeni Mshelia
- Primary Health Care Development Agency, Abuja, Nigeria
| | - Gatei wa Nganda
- Polio Elimination Branch, US Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | | | | | - Umar Chiroma
- Primary Health Care Development Agency, Abuja, Nigeria
| | - Stephanie Diane Kovacs
- Polio Elimination Branch, US Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Oladayo Biya
- Polio Elimination Branch, US Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | | | - Muyi Aina
- Solina Center for International Development and Research, Abuja, Nigeria
| | | | - Faisal Shuaib
- Primary Health Care Development Agency, Abuja, Nigeria
| | - Omotayo Bolu
- Polio Elimination Branch, US Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Richard Franka
- Polio Elimination Branch, US Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Eric Wiesen
- Polio Elimination Branch, US Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
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Claire Endegue M, Sein C, Lopez Cavestany R, Jeyaseelan V, Palmer T, Norbert Soke G, Diaha A, Jafri B, Mainou BA, Verma H, Mach O. Community-based survey to assess seroprevalence of poliovirus antibodies in far-north Cameroon in 2020. Vaccine X 2022; 12:100244. [PMID: 36560978 PMCID: PMC9763508 DOI: 10.1016/j.jvacx.2022.100244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 11/28/2022] [Accepted: 12/01/2022] [Indexed: 12/12/2022] Open
Abstract
Background This study assessed seroprevalence of poliovirus antibodies in children from selected poliovirus high-risk areas of the Far North region of Cameroon which serves to monitor polio immunization program. Methods This was a community-based cross-sectional seroprevalence survey involving collection of dried blood specimens (DBS) among children aged 12-59 months (n = 401). Multi-stage cluster sampling using GIS was applied to select the study sample. Collected DBS were analysed with microneutralization assays for poliovirus neutralizing antibody levels. Results The overall seroprevalence of types 1, 2 and 3 neutralizing antibodies were 86.8 % (95 % confidence interval [CI]: 83.1-89.8), 74.6 % (95 % CI: 70.1-78.6) and 79.3 % (95 % CI: 75.1-83.0), respectively. Median titers (log2 scale) for type 1, 2 and 3 were 7.17 (6.5-7.5), 5.17 (4.83-5.5), and 6.17 (5.5-6.5), respectively. There was an increasing trend in median titers and seroprevalence with age, statistically significant between the youngest and oldest age groups (p < 0.001). Conclusion Though there were several opportunities for vaccination through supplementary immunization activities (SIA) and routine immunization (RI), seroprevalence levels were low for all three serotypes, particularly for type 2. This highlights the need to strengthen RI and SIA quality coverage. Low population immunity makes Cameroon vulnerable to new importations and spread of polioviruses.
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Affiliation(s)
| | - Carolyn Sein
- Polio Eradication, World Health Organization HQ, 1211 Geneva, Switzerland
| | | | - Visalakshi Jeyaseelan
- Polio Eradication, World Health Organization HQ, 1211 Geneva, Switzerland,Corresponding author at: Polio Department, World Health Organization, Avenue Appia 20, CH-1211 Genève 27, Switzerland.
| | - Tess Palmer
- Global Immunization Division, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA
| | - Gnakub Norbert Soke
- Global Immunization Division, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA
| | - Aissata Diaha
- Global Immunization Division, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA
| | - Basit Jafri
- Population Immunity Laboratory, Polio and Picornavirus Branch, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA
| | - Bernardo A. Mainou
- Population Immunity Laboratory, Polio and Picornavirus Branch, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA
| | - Harish Verma
- Polio Eradication, World Health Organization HQ, 1211 Geneva, Switzerland
| | - Ondrej Mach
- Polio Eradication, World Health Organization HQ, 1211 Geneva, Switzerland
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Hsu CH, Wannemuehler KA, Soofi S, Mashal M, Hussain I, Bhutta ZA, McDuffie L, Weldon W, Farag NH. Poliovirus immunity among children under five years-old in accessible areas of Afghanistan, 2013. Vaccine 2019; 37:1577-1583. [PMID: 30782488 PMCID: PMC6466626 DOI: 10.1016/j.vaccine.2019.02.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 01/30/2019] [Accepted: 02/03/2019] [Indexed: 11/21/2022]
Abstract
BACKGROUND Afghanistan remains among the three countries with endemic wild poliovirus transmission, and high population immunity levels are required to interrupt transmission and prevent outbreaks. Surveillance and vaccination of children in Afghanistan have been challenging due to security issues limiting accessibility in certain areas. METHODS A serosurvey was conducted in 2013 within accessible enumeration areas (EAs) among children aged <5 years using samples collected for a national micronutrient assessment survey to assess poliovirus immunity in Afghanistan. Of 21194 total EAs in Afghanistan, 107 were inaccessible and therefore were excluded from the sampling frame. RESULTS Population immunity was high overall but varied for the poliovirus serotypes, and was lowest for type 3 (95% [95% CI: 93%, 96%]) compared to type 1 (99% [95% CI:97%, 99%]) and type 2 (98% [95% CI:96%, 99%]). The proportion of the population immune to all three types was 93% (95% CI: 91%, 95%), and the proportion seronegative for all three types was 0.5% (95% CI: 0.2%, 1.7%). CONCLUSION Except for regional differences in immunity to type 3 virus, there were no other apparent differences in seroprevalence by region or by any of the demographic or nutritional characteristics assessed in this study. The study was not powered to provide provincial level seroprevalence estimates, but Paktika Province, in the South region, had the largest proportion of seronegative specimens for type 1 (4 seronegative of 17 serum specimens compared to 14 seronegative of 673 for the remainder of the areas). Among accessible children in Afghanistan, seroprevalence of antibodies to poliovirus was high, with most seroprevalence reported at 95% or greater. Despite high seroprevalence in areas assessed in this study, the continued detection of poliovirus cases in the South and East regions indicate that overall regional vaccination coverage and performance is not sufficient to stop polio transmission.
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Affiliation(s)
- Christopher H Hsu
- Polio Eradication Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA.
| | | | - Sajid Soofi
- Woman and Child Health Division, Aga Khan University, Karachi, Pakistan
| | | | - Imtiaz Hussain
- Woman and Child Health Division, Aga Khan University, Karachi, Pakistan
| | - Zulfiqar A Bhutta
- Woman and Child Health Division, Aga Khan University, Karachi, Pakistan
| | | | - William Weldon
- Division of Viral Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Noha H Farag
- Polio Eradication Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA.
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