COVID-19 no Brasil: carga da doença, efetividade vacinal e efeitos da vacinação

Abstract

The COVID-19 pandemic has represented one of the most significant public health challenges of the 21st century. Brazil, one of the most affected countries, has implemented a broad vaccination program. This study aims to quantify the impact of COVID-19 and vaccination in the country. Through analysis of epidemiological data, we estimated (i) the burden of disease in terms of disability-adjusted life years (DALYs) in 2020, (ii) the effectiveness of the different vaccines used, (iii) the number of severe cases and deaths averted by immunisation, and (iv) how much receiving the COVID-19 vaccine affected the hospital stay of COVID-19 patients. COVID-19 has had a significant impact on the health of the Brazilian population, resulting in more than 5 million DALYs and, assuming that there were no major changes in disease burden between 2019 and 2020, the burden of COVID-19 would be classified as the leading cause of illness and disability in Brazil. We also observed that the primary vaccination schedule provided protection above 25% and 50%, respectively; even after 19 weeks, the booster doses conferred greater protection when compared to the primary schedule, with the heterologous doses providing greater protection than the booster doses of homologous vaccines. Vaccination in Brazil prevented a 74% increase in severe cases (n = 875,846) of COVID-19 and an 82% increase in deaths (n = 303,129) in the first year of the national vaccination campaign. Finally, we observed that the average length of hospital stay for those who received the vaccine was shorter than for those who were not vaccinated and that receiving at least one dose of the vaccine increased the probability of discharge compared to those who were not vaccinated. The results of the thesis contribute to a better understanding of the dynamics of the pandemic in Brazil and can assist in formulating public health policies.