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Estimating Vaccine-Driven Selection in Seasonal Influenza

Vaccination could be an evolutionary pressure on seasonal influenza if vaccines reduce the transmission rates of some (“targeted”) strains more than others. In theory, more vaccinated populations should have a lower prevalence of targeted strains compared to less vaccinated populations. We tested fo...

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Autores principales: Wen, Frank T., Bell, Sidney M., Bedford, Trevor, Cobey, Sarah
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6165116/
https://www.ncbi.nlm.nih.gov/pubmed/30231576
http://dx.doi.org/10.3390/v10090509
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author Wen, Frank T.
Bell, Sidney M.
Bedford, Trevor
Cobey, Sarah
author_facet Wen, Frank T.
Bell, Sidney M.
Bedford, Trevor
Cobey, Sarah
author_sort Wen, Frank T.
collection PubMed
description Vaccination could be an evolutionary pressure on seasonal influenza if vaccines reduce the transmission rates of some (“targeted”) strains more than others. In theory, more vaccinated populations should have a lower prevalence of targeted strains compared to less vaccinated populations. We tested for vaccine-induced selection in influenza by comparing strain frequencies between more and less vaccinated human populations. We defined strains in three ways: first as influenza types and subtypes, next as lineages of type B, and finally as clades of influenza A/H3N2. We detected spatial differences partially consistent with vaccine use in the frequencies of subtypes and types and between the lineages of influenza B, suggesting that vaccines do not select strongly among all these phylogenetic groups at regional scales. We did detect a significantly greater frequency of an H3N2 clade with known vaccine escape mutations in more vaccinated countries during the 2014–2015 season, which is consistent with vaccine-driven selection within the H3N2 subtype. Overall, we find more support for vaccine-driven selection when large differences in vaccine effectiveness suggest a strong effect size. Variation in surveillance practices across countries could obscure signals of selection, especially when strain-specific differences in vaccine effectiveness are small. Further examination of the influenza vaccine’s evolutionary effects would benefit from improvements in epidemiological surveillance and reporting.
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spelling pubmed-61651162018-10-11 Estimating Vaccine-Driven Selection in Seasonal Influenza Wen, Frank T. Bell, Sidney M. Bedford, Trevor Cobey, Sarah Viruses Article Vaccination could be an evolutionary pressure on seasonal influenza if vaccines reduce the transmission rates of some (“targeted”) strains more than others. In theory, more vaccinated populations should have a lower prevalence of targeted strains compared to less vaccinated populations. We tested for vaccine-induced selection in influenza by comparing strain frequencies between more and less vaccinated human populations. We defined strains in three ways: first as influenza types and subtypes, next as lineages of type B, and finally as clades of influenza A/H3N2. We detected spatial differences partially consistent with vaccine use in the frequencies of subtypes and types and between the lineages of influenza B, suggesting that vaccines do not select strongly among all these phylogenetic groups at regional scales. We did detect a significantly greater frequency of an H3N2 clade with known vaccine escape mutations in more vaccinated countries during the 2014–2015 season, which is consistent with vaccine-driven selection within the H3N2 subtype. Overall, we find more support for vaccine-driven selection when large differences in vaccine effectiveness suggest a strong effect size. Variation in surveillance practices across countries could obscure signals of selection, especially when strain-specific differences in vaccine effectiveness are small. Further examination of the influenza vaccine’s evolutionary effects would benefit from improvements in epidemiological surveillance and reporting. MDPI 2018-09-18 /pmc/articles/PMC6165116/ /pubmed/30231576 http://dx.doi.org/10.3390/v10090509 Text en © 2018 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Wen, Frank T.
Bell, Sidney M.
Bedford, Trevor
Cobey, Sarah
Estimating Vaccine-Driven Selection in Seasonal Influenza
title Estimating Vaccine-Driven Selection in Seasonal Influenza
title_full Estimating Vaccine-Driven Selection in Seasonal Influenza
title_fullStr Estimating Vaccine-Driven Selection in Seasonal Influenza
title_full_unstemmed Estimating Vaccine-Driven Selection in Seasonal Influenza
title_short Estimating Vaccine-Driven Selection in Seasonal Influenza
title_sort estimating vaccine-driven selection in seasonal influenza
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6165116/
https://www.ncbi.nlm.nih.gov/pubmed/30231576
http://dx.doi.org/10.3390/v10090509
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