Influenza vaccine effectiveness in preventing severe outcomes in patients hospitalized with laboratory-confirmed influenza during the 2017-2018 season. A retrospective cohort study in catalonia (spain)
Acosta, Lesly (Universitat Politècnica de Catalunya. Departament d'Estadística i Investigació Operativa)
Torner, Nuria (CIBER Epidemiología Salud Pública. CIBERESP. PREVICET Program)
Martínez, Ana (Servei Català de la Salut)
Ayneto, Xavier (Servei Català de la Salut)
Rius i Gibert, Maria Cristina (Agència de Salut Pública de Barcelona)
Jané i Checa, Mireia (Servei Català de la Salut)
Domínguez, Ángela (Universitat de Barcelona. Departament de Medicina)
Soldevila, Nuria (Universitat de Barcelona. Departament de Medicina)

Date:	2021
Abstract:	Seasonal influenza is a common cause of hospital admission, especially in older people and those with comorbidities. The objective of this study was to determine influenza vaccine effectiveness (VE) in preventing intensive care admissions and shortening the length of stay (LOS) in hospitalized laboratory-confirmed influenza cases (HLCI) in Catalonia (Spain). A retrospective cohort study was carried out during the 2017-2018 season in HLCI aged ≥18 years from 14 public hospitals. Differences in means and proportions were assessed using a t-test or a chi-square test as necessary and the differences were quantified using standardized effect measures: Cohen's d for quantitative and Cohen's w for categorical variables. Adjusted influenza vaccine effectiveness in preventing severity was estimated by multivariate logistic regression where the adjusted VE = (1 − adjusted odds ratio) · 100%; adjustment was also made using the propensity score. We analyzed 1414 HLCI aged ≥18 years; 465 (33%) were vaccinated, of whom 437 (94%) were aged ≥60 years, 269 (57. 8%) were male and 295 (63. 4%) were positive for influenza type B. ICU admission was required in 214 (15. 1%) cases. There were 141/1118 (12. 6%) ICU admissions in patients aged ≥60 years and 73/296 (24. 7%) in those aged <60 years (p < 0. 001). The mean LOS and ICU LOS did not differ significantly between vaccinated and unvaccinated patients. There were 52/465 (11. 2%) ICU admissions in vaccinated cases vs. 162/949 (17. 1%) in unvaccinated cases. Patients admitted to the ICU had a longer hospital LOS (mean: 22. 4 [SD 20. 3] days) than those who were not (mean: 11. 1 [SD 14. 4] days); p < 0. 001. Overall, vaccination was associated with a lower risk of ICU admission. Taking virus types A and B together, the estimated adjusted VE in preventing ICU admission was 31% (95% CI 1-52; p = 0. 04). When stratified by viral type, the aVE was 40% for type A (95% CI-11-68; p = 0. 09) and 25% for type B (95% CI-18-52; p = 0. 21). Annual influenza vaccination may prevent ICU admission in cases of HLCI. A non-significantly shorter mean hospital stay was observed in vaccinated cases. Our results support the need to increase vaccination uptake and public perception of the benefits of influenza vaccination in groups at a higher risk of hospitalization and severe outcomes.
Grants:	Agència de Gestió d'Ajuts Universitaris i de Recerca 2017SGR1342
Note:	Altres ajuts: Programme of Prevention, Surveillance and Control of Transmissible Diseases (PREVICET); CIBER de Epidemiología y Salud Pública (CIBERESP); Instituto de Salud Carlos III.
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Influenza; intensive care unit ; Vaccine effectiveness ; Length of stay
Published in:	Viruses, Vol. 13 Núm. 8 (august 2021) , p. 1465, ISSN 1999-4915

DOI: 10.3390/V13081465
PMID: 34452337

12 p, 2.7 MB

The record appears in these collections:
Research literature > UAB research groups literature > Research Centres and Groups (research output) > Health sciences and biosciences > Institut de Recerca Sant Pau
Articles > Research articles
Articles > Published articles