COVID-19 em idosos frágeis moradores de Instituições de Longa Permanência para Idosos: evidenciando a efetividade da vacinação

Abstract

Objectives: Evaluate the effectiveness of first, second and third COVID-19 vaccine doses, against infections, hospitalizations and deaths; and their association with frailty, age, sex and chronic disease, among older adults, in a social vulnerability context, residents of long-term care facilities (LTCF), in a middle-income country. Design: Retrospective cohort study. Setting and Participants: A total of 712 participants, of 29 LTCF, in Brazil. Methods: Continuous variables were described by medians and interquartile ranges and categorical variables were represented by absolute and relative frequencies. To compare continuous variables, the Mann-Whitney test was used. For evaluating the relation between categorical variables, Pearson's chi-square test and Z-test of proportion were applied. A significance level of 5% was considered. Results: Median age was 81.37 years, 72.8% were female, 94.61% were frail, 79.97% had a cognitive impairment, 69.54% had a mobility impairment, 78.37% have, at least, one chronic disease and 72.73% use five or more medications per day. Before the vaccine, mobility impairment was associated with great contamination rates (p=.03); frailty (p=.02) and previous pulmonary disease (p=.03) with symptoms; frailty (p=.02), pulmonary disease (p=.04) and male sex (p=.02) with emergency care or hospital admission. Following vaccination, none of these risk factors were found to be correlated with adverse outcomes. The number of positive cases (p=.001), symptomatic patients (p<.001), admissions (p=.001) and deaths (p<.001) were substantially reduced after the three vaccine doses. Conclusions and Implications: Even in a frail population, the vaccine was effective in the reduction of positive cases, the number of symptomatic patients, admission to emergency or hospital care and deaths. Before the vaccine, frailty, previous pulmonary disease and male sex were associated with worse outcomes. After the three vaccine doses, the proportion of these outcomes within those subgroups became equivalent to that observed in the remainder of the participant cohort.