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The potential impact of expanding target age groups for polio immunization campaigns
BACKGROUND: Global efforts to eradicate wild polioviruses (WPVs) continue to face challenges due to uninterrupted endemic WPV transmission in three countries and importation-related outbreaks into previously polio-free countries. We explore the potential role of including older children and adults i...
Autores principales: | , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
BioMed Central
2014
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3918103/ https://www.ncbi.nlm.nih.gov/pubmed/24472313 http://dx.doi.org/10.1186/1471-2334-14-45 |
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author | Duintjer Tebbens, Radboud J Kalkowska, Dominika A Wassilak, Steven GF Pallansch, Mark A Cochi, Stephen L Thompson, Kimberly M |
author_facet | Duintjer Tebbens, Radboud J Kalkowska, Dominika A Wassilak, Steven GF Pallansch, Mark A Cochi, Stephen L Thompson, Kimberly M |
author_sort | Duintjer Tebbens, Radboud J |
collection | PubMed |
description | BACKGROUND: Global efforts to eradicate wild polioviruses (WPVs) continue to face challenges due to uninterrupted endemic WPV transmission in three countries and importation-related outbreaks into previously polio-free countries. We explore the potential role of including older children and adults in supplemental immunization activities (SIAs) to more rapidly increase population immunity and prevent or stop transmission. METHODS: We use a differential equation-based dynamic poliovirus transmission model to analyze the epidemiological impact and vaccine resource implications of expanding target age groups in SIAs. We explore the use of older age groups in SIAs for three situations: alternative responses to the 2010 outbreak in Tajikistan, retrospective examination of elimination in two high-risk states in northern India, and prospective and retrospective strategies to accelerate elimination in endemic northwestern Nigeria. Our model recognizes the ability of individuals with waned mucosal immunity (i.e., immunity from a historical live poliovirus infection) to become re-infected and contribute to transmission to a limited extent. RESULTS: SIAs involving expanded age groups reduce overall caseloads, decrease transmission, and generally lead to a small reduction in the time to achieve WPV elimination. Analysis of preventive expanded age group SIAs in Tajikistan or prior to type-specific surges in incidence in high-risk areas of India and Nigeria showed the greatest potential benefits of expanded age groups. Analysis of expanded age group SIAs in outbreak situations or to accelerate the interruption of endemic transmission showed relatively less benefit, largely due to the circulation of WPV reaching individuals sooner or more effectively than the SIAs. The India and Nigeria results depend strongly on how well SIAs involving expanded age groups reach relatively isolated subpopulations that sustain clusters of susceptible children, which we assume play a key role in persistent endemic WPV transmission in these areas. CONCLUSIONS: This study suggests the need to carefully consider the epidemiological situation in the context of decisions to use expanded age group SIAs. Subpopulations of susceptible individuals may independently sustain transmission, which will reduce the overall benefits associated with using expanded age group SIAs to increase population immunity to a sufficiently high level to stop transmission and reduce the incidence of paralytic cases. |
format | Online Article Text |
id | pubmed-3918103 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2014 |
publisher | BioMed Central |
record_format | MEDLINE/PubMed |
spelling | pubmed-39181032014-02-09 The potential impact of expanding target age groups for polio immunization campaigns Duintjer Tebbens, Radboud J Kalkowska, Dominika A Wassilak, Steven GF Pallansch, Mark A Cochi, Stephen L Thompson, Kimberly M BMC Infect Dis Research Article BACKGROUND: Global efforts to eradicate wild polioviruses (WPVs) continue to face challenges due to uninterrupted endemic WPV transmission in three countries and importation-related outbreaks into previously polio-free countries. We explore the potential role of including older children and adults in supplemental immunization activities (SIAs) to more rapidly increase population immunity and prevent or stop transmission. METHODS: We use a differential equation-based dynamic poliovirus transmission model to analyze the epidemiological impact and vaccine resource implications of expanding target age groups in SIAs. We explore the use of older age groups in SIAs for three situations: alternative responses to the 2010 outbreak in Tajikistan, retrospective examination of elimination in two high-risk states in northern India, and prospective and retrospective strategies to accelerate elimination in endemic northwestern Nigeria. Our model recognizes the ability of individuals with waned mucosal immunity (i.e., immunity from a historical live poliovirus infection) to become re-infected and contribute to transmission to a limited extent. RESULTS: SIAs involving expanded age groups reduce overall caseloads, decrease transmission, and generally lead to a small reduction in the time to achieve WPV elimination. Analysis of preventive expanded age group SIAs in Tajikistan or prior to type-specific surges in incidence in high-risk areas of India and Nigeria showed the greatest potential benefits of expanded age groups. Analysis of expanded age group SIAs in outbreak situations or to accelerate the interruption of endemic transmission showed relatively less benefit, largely due to the circulation of WPV reaching individuals sooner or more effectively than the SIAs. The India and Nigeria results depend strongly on how well SIAs involving expanded age groups reach relatively isolated subpopulations that sustain clusters of susceptible children, which we assume play a key role in persistent endemic WPV transmission in these areas. CONCLUSIONS: This study suggests the need to carefully consider the epidemiological situation in the context of decisions to use expanded age group SIAs. Subpopulations of susceptible individuals may independently sustain transmission, which will reduce the overall benefits associated with using expanded age group SIAs to increase population immunity to a sufficiently high level to stop transmission and reduce the incidence of paralytic cases. BioMed Central 2014-01-29 /pmc/articles/PMC3918103/ /pubmed/24472313 http://dx.doi.org/10.1186/1471-2334-14-45 Text en Copyright © 2014 Duintjer Tebbens et al.; licensee BioMed Central Ltd. http://creativecommons.org/licenses/by/2.0 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. |
spellingShingle | Research Article Duintjer Tebbens, Radboud J Kalkowska, Dominika A Wassilak, Steven GF Pallansch, Mark A Cochi, Stephen L Thompson, Kimberly M The potential impact of expanding target age groups for polio immunization campaigns |
title | The potential impact of expanding target age groups for polio immunization campaigns |
title_full | The potential impact of expanding target age groups for polio immunization campaigns |
title_fullStr | The potential impact of expanding target age groups for polio immunization campaigns |
title_full_unstemmed | The potential impact of expanding target age groups for polio immunization campaigns |
title_short | The potential impact of expanding target age groups for polio immunization campaigns |
title_sort | potential impact of expanding target age groups for polio immunization campaigns |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3918103/ https://www.ncbi.nlm.nih.gov/pubmed/24472313 http://dx.doi.org/10.1186/1471-2334-14-45 |
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