Avoidable COVID-19-related deaths and hospitalizations in Brazil, 2020-2023.

Objective: To estimate the number of avoidable COVID-19 deaths and hospitalizations in Brazil.

Methods: Secondary data on COVID-19 deaths and hospitalizations were related to two measures of cumulative vaccine coverage (in the last six months and before this period) by negative binomial regression to estimate population-level protective effectiveness (PLPE) against severe disease. The latter includes the overall protective effect of all COVID-19-preventive measures, such as direct and indirect vaccine effectiveness, social distancing, and lockdown, but only the vaccine coverage data were available for the regression analysis.

Results: COVID-19 mortality rates per 100,000 inhabitants were 10.26, 16.45, 0.14, and 0.94, for the years 2020, 2021, 2022, and the first half of 2023. In the same order and scale, COVID-19 hospitalization rates were 28.96, 47.04, 0.40, and 3.74. Both hospitalizations and deaths peaked early in 2021, then sharply reduced by the end of the year as the first-dose vaccine coverage reached 90 %, and rose with the vaccine coverage within the last six months falling below 10 % in 2023. PLPE for preventing COVID-19 deaths was 19.9 %, 98.9 %, and 93.1 % for the years 2021, 2022, and the first half of 2023. Had Brazil vaccinated the same number of people against COVID-19 in the last quarter of 2020 as it did in the first quarter of 2021, over 117,000 deaths and 277,000 hospitalizations could have been avoided over the period analyzed.

Conclusions: PLPE reduction in 2023 was likely caused by low vaccine uptake. The disease burden could have been much lower had the vaccination started earlier and had the vaccine uptake not dropped so sharply in 2023.