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Transmissibility of influenza during the 21st-century epidemics, Spain, influenza seasons 2001/02 to 2017/18

BACKGROUND: Understanding influenza seasonality is necessary for determining policies for influenza control. AIM: We characterised transmissibility during seasonal influenza epidemics, including one influenza pandemic, in Spain during the 21th century by using the moving epidemic method (MEM) to cal...

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Autores principales: Redondo-Bravo, Lidia, Delgado-Sanz, Concepción, Oliva, Jesús, Vega, Tomás, Lozano, Jose, Larrauri, Amparo
Formato: Online Artículo Texto
Lenguaje:English
Publicado: European Centre for Disease Prevention and Control (ECDC) 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7268270/
https://www.ncbi.nlm.nih.gov/pubmed/32489178
http://dx.doi.org/10.2807/1560-7917.ES.2020.25.21.1900364
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author Redondo-Bravo, Lidia
Delgado-Sanz, Concepción
Oliva, Jesús
Vega, Tomás
Lozano, Jose
Larrauri, Amparo
author_facet Redondo-Bravo, Lidia
Delgado-Sanz, Concepción
Oliva, Jesús
Vega, Tomás
Lozano, Jose
Larrauri, Amparo
author_sort Redondo-Bravo, Lidia
collection PubMed
description BACKGROUND: Understanding influenza seasonality is necessary for determining policies for influenza control. AIM: We characterised transmissibility during seasonal influenza epidemics, including one influenza pandemic, in Spain during the 21th century by using the moving epidemic method (MEM) to calculate intensity levels and estimate differences across seasons and age groups. METHODS: We applied the MEM to Spanish Influenza Sentinel Surveillance System data from influenza seasons 2001/02 to 2017/18. A modified version of Goldstein’s proxy was used as an epidemiological-virological parameter. We calculated the average starting week and peak, the length of the epidemic period and the length from the starting week to the peak of the epidemic, by age group and according to seasonal virus circulation. RESULTS: Individuals under 15 years of age presented higher transmissibility, especially in the 2009 influenza A(H1N1) pandemic. Seasons with dominance/co-dominance of influenza A(H3N2) virus presented high intensities in older adults. The 2004/05 influenza season showed the highest influenza-intensity level for all age groups. In 12 seasons, the epidemic started between week 50 and week 3. Epidemics started earlier in individuals under 15 years of age (−1.8 weeks; 95% confidence interval (CI):−2.8 to −0.7) than in those over 64 years when influenza B virus circulated as dominant/co-dominant. The average time from start to peak was 4.3 weeks (95% CI: 3.6–5.0) and the average epidemic length was 8.7 weeks (95% CI: 7.9–9.6). CONCLUSIONS: These findings provide evidence for intensity differences across seasons and age groups, and can be used guide public health actions to diminish influenza-related morbidity and mortality.
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spelling pubmed-72682702020-06-04 Transmissibility of influenza during the 21st-century epidemics, Spain, influenza seasons 2001/02 to 2017/18 Redondo-Bravo, Lidia Delgado-Sanz, Concepción Oliva, Jesús Vega, Tomás Lozano, Jose Larrauri, Amparo Euro Surveill Research BACKGROUND: Understanding influenza seasonality is necessary for determining policies for influenza control. AIM: We characterised transmissibility during seasonal influenza epidemics, including one influenza pandemic, in Spain during the 21th century by using the moving epidemic method (MEM) to calculate intensity levels and estimate differences across seasons and age groups. METHODS: We applied the MEM to Spanish Influenza Sentinel Surveillance System data from influenza seasons 2001/02 to 2017/18. A modified version of Goldstein’s proxy was used as an epidemiological-virological parameter. We calculated the average starting week and peak, the length of the epidemic period and the length from the starting week to the peak of the epidemic, by age group and according to seasonal virus circulation. RESULTS: Individuals under 15 years of age presented higher transmissibility, especially in the 2009 influenza A(H1N1) pandemic. Seasons with dominance/co-dominance of influenza A(H3N2) virus presented high intensities in older adults. The 2004/05 influenza season showed the highest influenza-intensity level for all age groups. In 12 seasons, the epidemic started between week 50 and week 3. Epidemics started earlier in individuals under 15 years of age (−1.8 weeks; 95% confidence interval (CI):−2.8 to −0.7) than in those over 64 years when influenza B virus circulated as dominant/co-dominant. The average time from start to peak was 4.3 weeks (95% CI: 3.6–5.0) and the average epidemic length was 8.7 weeks (95% CI: 7.9–9.6). CONCLUSIONS: These findings provide evidence for intensity differences across seasons and age groups, and can be used guide public health actions to diminish influenza-related morbidity and mortality. European Centre for Disease Prevention and Control (ECDC) 2020-05-28 /pmc/articles/PMC7268270/ /pubmed/32489178 http://dx.doi.org/10.2807/1560-7917.ES.2020.25.21.1900364 Text en This article is copyright of the authors or their affiliated institutions, 2020. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution (CC BY 4.0) Licence. You may share and adapt the material, but must give appropriate credit to the source, provide a link to the licence, and indicate if changes were made.
spellingShingle Research
Redondo-Bravo, Lidia
Delgado-Sanz, Concepción
Oliva, Jesús
Vega, Tomás
Lozano, Jose
Larrauri, Amparo
Transmissibility of influenza during the 21st-century epidemics, Spain, influenza seasons 2001/02 to 2017/18
title Transmissibility of influenza during the 21st-century epidemics, Spain, influenza seasons 2001/02 to 2017/18
title_full Transmissibility of influenza during the 21st-century epidemics, Spain, influenza seasons 2001/02 to 2017/18
title_fullStr Transmissibility of influenza during the 21st-century epidemics, Spain, influenza seasons 2001/02 to 2017/18
title_full_unstemmed Transmissibility of influenza during the 21st-century epidemics, Spain, influenza seasons 2001/02 to 2017/18
title_short Transmissibility of influenza during the 21st-century epidemics, Spain, influenza seasons 2001/02 to 2017/18
title_sort transmissibility of influenza during the 21st-century epidemics, spain, influenza seasons 2001/02 to 2017/18
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7268270/
https://www.ncbi.nlm.nih.gov/pubmed/32489178
http://dx.doi.org/10.2807/1560-7917.ES.2020.25.21.1900364
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