[Source: Eurosurveillance, full page: (LINK). Abstract, edited.]
Influenza vaccine effectiveness against laboratory-confirmed influenza in hospitalised adults aged 60 years or older, Valencia Region, Spain, 2017/18 influenza season
Ainara Mira-Iglesias 1, F Xavier López-Labrador 1,2, Víctor Baselga-Moreno 1, Miguel Tortajada-Girbés 3, Juan Mollar-Maseres 4,Mario Carballido-Fernández 5,6, Germán Schwarz-Chavarri 7, Joan Puig-Barberà 1,8, Javier Díez-Domingo 1,on behalf of the Valencia Hospital Network for the Study of Influenza and Respiratory Viruses Disease 9
Affiliations: 1 Fundación para el Fomento de la Investigación Sanitaria y Biomédica de la Comunitat Valenciana (FISABIO-Public Health), Valencia, Spain; 2 Consorcio de Investigación Biomédica de Epidemiología y Salud Pública (CIBERESP), Instituto de Salud Carlos III, Madrid, Spain; 3 Hospital Doctor Peset, Valencia, Spain; 4 Hospital Universitario y Politécnico La Fe, Valencia, Spain; 5 Hospital General Universitario de Castellón, Castellón, Spain; 6 Universidad CEU Cardenal Herrera, Castellón, Spain; 7 Hospital General de Alicante, Alicante, Spain; 8 Centro de Salud Pública de Castellón, Castellón, Spain; 9 The Network members are acknowledged at the end of the article
Correspondence: Javier Díez-Domingo
Citation style for this article: Mira-Iglesias Ainara, López-Labrador F Xavier, Baselga-Moreno Víctor, Tortajada-Girbés Miguel, Mollar-Maseres Juan,Carballido-Fernández Mario, Schwarz-Chavarri Germán, Puig-Barberà Joan, Díez-Domingo Javier,on behalf of the Valencia Hospital Network for the Study of Influenza and Respiratory Viruses Disease. Influenza vaccine effectiveness against laboratory-confirmed influenza in hospitalised adults aged 60 years or older, Valencia Region, Spain, 2017/18 influenza season. Euro Surveill. 2019;24(31):pii=1800461. https://doi.org/10.2807/1560-7917.ES.2019.24.31.1800461
Received: 21 Aug 2018; Accepted: 05 Mar 2019
Influenza immunisation is recommended for elderly people each season. The influenza vaccine effectiveness (IVE) varies annually due to influenza viruses evolving and the vaccine composition.
To estimate, in inpatients ≥ 60 years old, the 2017/18 trivalent IVE, overall, by vaccine type and by strain. The impact of vaccination in any of the two previous seasons (2016/17 and 2015/16) on current (2017/18) IVE was also explored.
This was a multicentre prospective observational study within the Valencia Hospital Surveillance Network for the Study of Influenza and Respiratory Viruses Disease (VAHNSI, Spain). The test-negative design was applied taking laboratory-confirmed influenza as outcome and vaccination status as main exposure. Information about potential confounders was obtained from clinical registries and/or by interviewing patients; vaccine information was only ascertained by registries.
Overall, 2017/18 IVE was 9.9% (95% CI: −15.5 to 29.6%), and specifically, 48.3% (95% CI: 13.5% to 69.1%), −29.9% (95% CI: −79.1% to 5.8%) and 25.7% (95% CI: −8.8% to 49.3%) against A(H1N1)pdm09, A(H3N2) and B/Yamagata lineage, respectively. For the adjuvanted and non-adjuvanted vaccines, overall IVE was 10.0% (95% CI: −24.4% to 34.9%) and 7.8% (95% CI: −23.1% to 31.0%) respectively. Prior vaccination significantly protected against influenza B/Yamagata lineage (IVE: 50.2%; 95% CI: 2.3% to 74.6%) in patients not vaccinated in the current season. For those repeatedly vaccinated against influenza A(H1N1)pdm09, IVE was 46.4% (95% CI: 6.8% to 69.2%).
Our data revealed low vaccine effectiveness against influenza in hospitalised patients ≥60 years old in 2017/18. Prior vaccination protected against influenza A(H1N1)pdm09 and B/Yamagata-lineage.
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Keywords: Seasonal Influenza; H1N1pdm09; H3N2; Influenza B; Vaccines; Spain.