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4Flu - an individual based simulation tool to study the effects of quadrivalent vaccination on seasonal influenza in Germany

BACKGROUND: Influenza vaccines contain Influenza A and B antigens and are adjusted annually to match the characteristics of circulating viruses. In Germany, Influenza B viruses belonged to the B/Yamagata lineage, but since 2001, the antigenically distinct B/Victoria lineage has been co-circulating....

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Autores principales: Eichner, Martin, Schwehm, Markus, Hain, Johannes, Uphoff, Helmut, Salzberger, Bernd, Knuf, Markus, Schmidt-Ott, Ruprecht
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2014
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4099094/
https://www.ncbi.nlm.nih.gov/pubmed/24993051
http://dx.doi.org/10.1186/1471-2334-14-365
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author Eichner, Martin
Schwehm, Markus
Hain, Johannes
Uphoff, Helmut
Salzberger, Bernd
Knuf, Markus
Schmidt-Ott, Ruprecht
author_facet Eichner, Martin
Schwehm, Markus
Hain, Johannes
Uphoff, Helmut
Salzberger, Bernd
Knuf, Markus
Schmidt-Ott, Ruprecht
author_sort Eichner, Martin
collection PubMed
description BACKGROUND: Influenza vaccines contain Influenza A and B antigens and are adjusted annually to match the characteristics of circulating viruses. In Germany, Influenza B viruses belonged to the B/Yamagata lineage, but since 2001, the antigenically distinct B/Victoria lineage has been co-circulating. Trivalent influenza vaccines (TIV) contain antigens of the two A subtypes A(H3N2) and A(H1N1), yet of only one B lineage, resulting in frequent vaccine mismatches. Since 2012, the WHO has been recommending vaccine strains from both B lineages, paving the way for quadrivalent influenza vaccines (QIV). METHODS: Using an individual-based simulation tool, we simulate the concomitant transmission of four influenza strains, and compare the effects of TIV and QIV on the infection incidence. Individuals are connected in a dynamically evolving age-dependent contact network based on the POLYMOD matrix; their age-distribution reproduces German demographic data and predictions. The model considers maternal protection, boosting of existing immunity, loss of immunity, and cross-immunizing events between the B lineages. Calibration to the observed annual infection incidence of 10.6% among young adults yielded a basic reproduction number of 1.575. Vaccinations are performed annually in October and November, whereby coverage depends on the vaccinees’ age, their risk status and previous vaccination status. New drift variants are introduced at random time points, leading to a sudden loss of protective immunity for part of the population and occasionally to reduced vaccine efficacy. Simulations run for 50 years, the first 30 of which are used for initialization. During the final 20 years, individuals receive TIV or QIV, using a mirrored simulation approach. RESULTS: Using QIV, the mean annual infection incidence can be reduced from 8,943,000 to 8,548,000, i.e. by 395,000 infections, preventing 11.2% of all Influenza B infections which still occur with TIV (95% CI: 10.7-11.8%). Using a lower B lineage cross protection than the baseline 60%, the number of Influenza B infections increases and the number additionally prevented by QIV can be 5.5 times as high. CONCLUSIONS: Vaccination with TIV substantially reduces the Influenza incidence compared to no vaccination. Depending on the assumed degree of B lineage cross protection, QIV further reduces Influenza B incidence by 11-33%.
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spelling pubmed-40990942014-07-25 4Flu - an individual based simulation tool to study the effects of quadrivalent vaccination on seasonal influenza in Germany Eichner, Martin Schwehm, Markus Hain, Johannes Uphoff, Helmut Salzberger, Bernd Knuf, Markus Schmidt-Ott, Ruprecht BMC Infect Dis Research Article BACKGROUND: Influenza vaccines contain Influenza A and B antigens and are adjusted annually to match the characteristics of circulating viruses. In Germany, Influenza B viruses belonged to the B/Yamagata lineage, but since 2001, the antigenically distinct B/Victoria lineage has been co-circulating. Trivalent influenza vaccines (TIV) contain antigens of the two A subtypes A(H3N2) and A(H1N1), yet of only one B lineage, resulting in frequent vaccine mismatches. Since 2012, the WHO has been recommending vaccine strains from both B lineages, paving the way for quadrivalent influenza vaccines (QIV). METHODS: Using an individual-based simulation tool, we simulate the concomitant transmission of four influenza strains, and compare the effects of TIV and QIV on the infection incidence. Individuals are connected in a dynamically evolving age-dependent contact network based on the POLYMOD matrix; their age-distribution reproduces German demographic data and predictions. The model considers maternal protection, boosting of existing immunity, loss of immunity, and cross-immunizing events between the B lineages. Calibration to the observed annual infection incidence of 10.6% among young adults yielded a basic reproduction number of 1.575. Vaccinations are performed annually in October and November, whereby coverage depends on the vaccinees’ age, their risk status and previous vaccination status. New drift variants are introduced at random time points, leading to a sudden loss of protective immunity for part of the population and occasionally to reduced vaccine efficacy. Simulations run for 50 years, the first 30 of which are used for initialization. During the final 20 years, individuals receive TIV or QIV, using a mirrored simulation approach. RESULTS: Using QIV, the mean annual infection incidence can be reduced from 8,943,000 to 8,548,000, i.e. by 395,000 infections, preventing 11.2% of all Influenza B infections which still occur with TIV (95% CI: 10.7-11.8%). Using a lower B lineage cross protection than the baseline 60%, the number of Influenza B infections increases and the number additionally prevented by QIV can be 5.5 times as high. CONCLUSIONS: Vaccination with TIV substantially reduces the Influenza incidence compared to no vaccination. Depending on the assumed degree of B lineage cross protection, QIV further reduces Influenza B incidence by 11-33%. BioMed Central 2014-07-03 /pmc/articles/PMC4099094/ /pubmed/24993051 http://dx.doi.org/10.1186/1471-2334-14-365 Text en Copyright © 2014 Eichner 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 credited.
spellingShingle Research Article
Eichner, Martin
Schwehm, Markus
Hain, Johannes
Uphoff, Helmut
Salzberger, Bernd
Knuf, Markus
Schmidt-Ott, Ruprecht
4Flu - an individual based simulation tool to study the effects of quadrivalent vaccination on seasonal influenza in Germany
title 4Flu - an individual based simulation tool to study the effects of quadrivalent vaccination on seasonal influenza in Germany
title_full 4Flu - an individual based simulation tool to study the effects of quadrivalent vaccination on seasonal influenza in Germany
title_fullStr 4Flu - an individual based simulation tool to study the effects of quadrivalent vaccination on seasonal influenza in Germany
title_full_unstemmed 4Flu - an individual based simulation tool to study the effects of quadrivalent vaccination on seasonal influenza in Germany
title_short 4Flu - an individual based simulation tool to study the effects of quadrivalent vaccination on seasonal influenza in Germany
title_sort 4flu - an individual based simulation tool to study the effects of quadrivalent vaccination on seasonal influenza in germany
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4099094/
https://www.ncbi.nlm.nih.gov/pubmed/24993051
http://dx.doi.org/10.1186/1471-2334-14-365
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