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Is the impact of childhood influenza vaccination less than expected: a transmission modelling study
BACKGROUND: To reduce the burden of severe influenza, most industrialized countries target specific risk-groups with influenza vaccines, e.g. the elderly or individuals with comorbidities. Since children are the main spreaders, some countries have recently implemented childhood vaccination programs...
Autores principales: | , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
BioMed Central
2017
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5387286/ https://www.ncbi.nlm.nih.gov/pubmed/28399801 http://dx.doi.org/10.1186/s12879-017-2344-6 |
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author | Weidemann, Felix Remschmidt, Cornelius Buda, Silke Buchholz, Udo Ultsch, Bernhard Wichmann, Ole |
author_facet | Weidemann, Felix Remschmidt, Cornelius Buda, Silke Buchholz, Udo Ultsch, Bernhard Wichmann, Ole |
author_sort | Weidemann, Felix |
collection | PubMed |
description | BACKGROUND: To reduce the burden of severe influenza, most industrialized countries target specific risk-groups with influenza vaccines, e.g. the elderly or individuals with comorbidities. Since children are the main spreaders, some countries have recently implemented childhood vaccination programs to reduce overall virus transmission and thereby influenza disease in the whole population. The introduction of childhood vaccination programs was often supported by modelling studies that predicted substantial incidence reductions. We developed a mathematical transmission model to examine the potential impact of childhood influenza vaccination in Germany, while also challenging established modelling assumptions. METHODS: We developed an age-stratified SEIR-type transmission model to reproduce the epidemic influenza seasons between 2003/04 and 2013/14. The model was built upon German population counts, contact patterns, and vaccination history and was fitted to seasonal data on influenza-attributable medically attended acute respiratory infections (I-MAARI) and strain distribution using Bayesian methods. As novelties we (i) implemented a stratified model structure enabling seasonal variability and (ii) deviated from the commonly assumed mass-action-principle by employing a phenomenological transmission rate. RESULTS: According to the model, by vaccinating primarily the elderly over ten seasons 4 million (95% prediction interval: 3.84 – 4.19) I-MAARI were prevented which corresponds to an 8.6% (8.3% – 8.9%) reduction compared to a no-vaccination scenario and a number-needed-to-vaccinate (NNV) to prevent one I-MAARI of 37.1 (35.5 – 38.7). Additional vaccination of 2-10 year-old children at 40% coverage would have led to an overall I-MAARI reduction of 17.8% (17.1 – 18.7%) mostly due to indirect effects with a NNV of 20.7 (19.6 – 21.6). When employing the traditional mass-action-principle, the model predicted a more than 3-fold higher I-MAARI reduction (55.6%) due to childhood vaccination. CONCLUSION: In Germany, the introduction of routine childhood influenza vaccination could considerably reduce I-MAARI among all age-groups and improve the NNV. However, the predicted impact is much lower compared to previous studies, which is primarily caused by our phenomenological approach to modelling influenza virus transmission. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12879-017-2344-6) contains supplementary material, which is available to authorized users. |
format | Online Article Text |
id | pubmed-5387286 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2017 |
publisher | BioMed Central |
record_format | MEDLINE/PubMed |
spelling | pubmed-53872862017-04-11 Is the impact of childhood influenza vaccination less than expected: a transmission modelling study Weidemann, Felix Remschmidt, Cornelius Buda, Silke Buchholz, Udo Ultsch, Bernhard Wichmann, Ole BMC Infect Dis Research Article BACKGROUND: To reduce the burden of severe influenza, most industrialized countries target specific risk-groups with influenza vaccines, e.g. the elderly or individuals with comorbidities. Since children are the main spreaders, some countries have recently implemented childhood vaccination programs to reduce overall virus transmission and thereby influenza disease in the whole population. The introduction of childhood vaccination programs was often supported by modelling studies that predicted substantial incidence reductions. We developed a mathematical transmission model to examine the potential impact of childhood influenza vaccination in Germany, while also challenging established modelling assumptions. METHODS: We developed an age-stratified SEIR-type transmission model to reproduce the epidemic influenza seasons between 2003/04 and 2013/14. The model was built upon German population counts, contact patterns, and vaccination history and was fitted to seasonal data on influenza-attributable medically attended acute respiratory infections (I-MAARI) and strain distribution using Bayesian methods. As novelties we (i) implemented a stratified model structure enabling seasonal variability and (ii) deviated from the commonly assumed mass-action-principle by employing a phenomenological transmission rate. RESULTS: According to the model, by vaccinating primarily the elderly over ten seasons 4 million (95% prediction interval: 3.84 – 4.19) I-MAARI were prevented which corresponds to an 8.6% (8.3% – 8.9%) reduction compared to a no-vaccination scenario and a number-needed-to-vaccinate (NNV) to prevent one I-MAARI of 37.1 (35.5 – 38.7). Additional vaccination of 2-10 year-old children at 40% coverage would have led to an overall I-MAARI reduction of 17.8% (17.1 – 18.7%) mostly due to indirect effects with a NNV of 20.7 (19.6 – 21.6). When employing the traditional mass-action-principle, the model predicted a more than 3-fold higher I-MAARI reduction (55.6%) due to childhood vaccination. CONCLUSION: In Germany, the introduction of routine childhood influenza vaccination could considerably reduce I-MAARI among all age-groups and improve the NNV. However, the predicted impact is much lower compared to previous studies, which is primarily caused by our phenomenological approach to modelling influenza virus transmission. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12879-017-2344-6) contains supplementary material, which is available to authorized users. BioMed Central 2017-04-11 /pmc/articles/PMC5387286/ /pubmed/28399801 http://dx.doi.org/10.1186/s12879-017-2344-6 Text en © The Author(s). 2017 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. 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 Weidemann, Felix Remschmidt, Cornelius Buda, Silke Buchholz, Udo Ultsch, Bernhard Wichmann, Ole Is the impact of childhood influenza vaccination less than expected: a transmission modelling study |
title | Is the impact of childhood influenza vaccination less than expected: a transmission modelling study |
title_full | Is the impact of childhood influenza vaccination less than expected: a transmission modelling study |
title_fullStr | Is the impact of childhood influenza vaccination less than expected: a transmission modelling study |
title_full_unstemmed | Is the impact of childhood influenza vaccination less than expected: a transmission modelling study |
title_short | Is the impact of childhood influenza vaccination less than expected: a transmission modelling study |
title_sort | is the impact of childhood influenza vaccination less than expected: a transmission modelling study |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5387286/ https://www.ncbi.nlm.nih.gov/pubmed/28399801 http://dx.doi.org/10.1186/s12879-017-2344-6 |
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