Effectiveness of influenza vaccine in preventing severe influenza

Introduction: Influenza is one of the diseases with the greatest epidemiological impact and the greatest relevance in the management of health services. The flu vaccine can have great variability each season, so our objective was to know the effectiveness of the flu vaccine for the 2017/2018 season for the prevention of severe cases of flu in a general acute hospital in 385 beds. Material and method: Case control study. All hospitalized patients with laboratory confirmed influenza during the 2017/2018 season were included. Those who met the criteria for a severe case of influenza were considered cases. Those that did not meet the severity criteria were considered controls. The factors associated with the development of severe influenza were calculated. Results: The effectiveness adjusted by age group and comorbidity was 60.7% (20.5-80.5). The vaccinated and unvaccinated groups were different in terms of age (P < .0381). The highest proportion of cases were concentrated in those over 65 years of age (45.5%). Vaccination status against severe influenza was found to be an independent protective factor (OR = .746; .694-.831). Conclusions: The effectiveness of influenza vaccination provided greater protection against infection and reduced the severity of influenza in hospitalized patients. These findings should be considered to improve vaccination strategies and achieve better vaccination coverage in the population at risk. (C) 2022 FECA. Published by Elsevier Espana, S.L.U. All rights reserved.