Vaccine effectiveness in preventing deaths in people with severe acute respiratory syndrome due to COVID-19 in Blumenau, Brazil, 2021

ABSTRACT Objective to analyze the vaccine effectiveness in preventing deaths attributed to severe acute respiratory syndrome due to COVID-19 (SARS/COVID-19) in adults and the elderly, in Blumenau, state of Santa Catarina, Brazil, 2021. this was a population-based study conducted among individuals aged 20 years and older hospitalized with SARS/COVID-19; each death due to SARS/COVID-19 was considered a “case”, and every survivor was considered a “control”; the association between vaccination status and the outcome of “death” was estimated using logistic regression, and vaccine effectiveness was estimated as (1-OR)*100. The study included 1,756 cases of SARS/COVID-19 (59.2% male, mean age of 56 years, 50.4% with elementary education, 68.4% with comorbidities and 39.1% in intensive care), of whom 398 died (cases) and 1,358 survived (controls); vaccine effectiveness was 74% and 85% (20-59 years old) and 72% and 75% (≥ 60 years old), respectively, for those who were partially vaccinated and fully vaccinated. Conclusion vaccines proved to be effective in reducing case fatality ratio due to SARS/COVID-19 in individuals ≥ 20 years old.