ABSTRACT
Background: With the outbreak of the COVID-19 pandemic, safe and efficacious vaccines were quickly developed and made available to reduce its morbidity and mortality. This study aimed to describe the trends and evaluate the association of COVID-19 vaccination with indicators of morbidity and mortality due to the disease in Brazil. Methods: : This was an ecological study whose unit of analysis was the time elapsed between February 16th, 2020, from the introduction of COVID-19 in Brazil and July 17th, 2021, six months after the start of vaccination in the country. From secondary databases, indicators of morbidity and mortality (incidence of hospitalization, proportion of severe cases, lethality and mortality) and vaccine coverage (doses 1, 2 or single dose) per epidemiological week (EW) and age groups were calculated (18 to 59 years and 60 years or older). Indicators of morbimortality were compared in the pre-vaccination (EW 8/2020 to EW 2/2021) and vaccination (EW 3/2021 to EW 28/2021) periods, analyzing the trends estimated using the JointPoint model and their associations using the Poisson model. Results: : For individuals aged 60 years and over, during the period of COVID-19 vaccination there was a weekly trend towards a reduction in the incidence of hospitalizations (PMSV: -4.7%), severity (PMSV: -0.3%, lethality (PMSV: -2.0%) and mortality (PMSV: -2.8%); the increase in COVID-19 vaccination coverage was inversely associated with the incidence of hospitalizations (IRR: 0.969), lethality (IRR: 0.993), and mortality (IRR: 0.981). For individuals aged 18 to 59 years of age, during the period of COVID-19 vaccination there was a weekly trend towards a reduction in the incidence of hospitalizations (PMSV: -2.6%) and lethality (PMSV: -2.0%), while there was an increase in mortality (PMSV: 3.8%); the increase in COVID-19 vaccination coverage was inversely associated with the incidence of hospitalizations (IRR: 0.975) and lethality (IRR: 0.939). Conversely, it was directly associated with mortality (IRR: 1.054). Conclusions: : it was demonstrated that COVID-19 vaccination had an indirect impact in reducing the morbidity and mortality trend from the disease in Brazil, especially in the elderly population, in which vaccination was prioritized and achieved greater coverage, when compared to individuals aged 18 to 59 years.