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)
Por:
Acosta, L, Soldevila, N, Torner, N, Martinez, A, Ayneto, X, Rius, C, Jane, M, Dominguez, A
Publicada:
1 ago 2021
Resumen:
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) center dot 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.
Filiaciones:
Acosta, L:
Polytech Univ Catalonia BARCELONATECH, Dept Stat & Operat Res, E-08028 Barcelona, Spain
Soldevila, N:
CIBERESP, CIBER Epidemiol Salud Publ, PREVICET Program, E-28029 Madrid, Spain
Univ Barcelona, Dept Med, E-08036 Barcelona, Spain
Torner, N:
CIBERESP, CIBER Epidemiol Salud Publ, PREVICET Program, E-28029 Madrid, Spain
Martinez, A:
CIBERESP, CIBER Epidemiol Salud Publ, PREVICET Program, E-28029 Madrid, Spain
Publ Hlth Agcy Catalonia, E-08005 Barcelona, Spain
Ayneto, X:
Publ Hlth Agcy Catalonia, E-08005 Barcelona, Spain
Rius, C:
CIBERESP, CIBER Epidemiol Salud Publ, PREVICET Program, E-28029 Madrid, Spain
Publ Hlth Agcy Barcelona, E-08024 Barcelona, Spain
Jane, M:
CIBERESP, CIBER Epidemiol Salud Publ, PREVICET Program, E-28029 Madrid, Spain
Univ Barcelona, Dept Med, E-08036 Barcelona, Spain
Publ Hlth Agcy Catalonia, E-08005 Barcelona, Spain
Dominguez, A:
CIBERESP, CIBER Epidemiol Salud Publ, PREVICET Program, E-28029 Madrid, Spain
Univ Barcelona, Dept Med, E-08036 Barcelona, Spain
Green Published, Green Submitted, gold
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