EFFECT-Brazil is one of the 10 driver projects selected among 400+ proposals for the Grand Challenge of the International COVID-19 Data Alliance (ICODA) Data Science initiative and funded by the Gates Foundation.

Brazil is one of the most addected countries by the COVID-19 pandemic and has evolved as a hotspot of the new SARS-SoV-2 variants of concern (VOC). Even with worrying numbers of cases and deaths, the vaccination process progresses slowly. Only in the best-case scenario, the majority of its 200 million habitants will be vaccinated before 2022. Besides, Brazil has a nathional health system (SUS) and an extensive public immunization program (National Program of Immunization - PNI).

Our central question in "What is the COVID-19 effectiveness in Brazil?". Hence, we aim to estimate both individual and population vaccine effectiveness, respectively:

(i) in preventing hospitalization of moderate to severe cases, and

(ii) in reducing the transmission accouting for inequities in vaccine access.

For the individual effectiveness, we will address a test-negative design using data of patients admitted at 43 hospitals from the largest hospital network in Latin America, Rede D'or São Luis. For the populational effectiveness, we will perform an ecological study to estimate the vaccine impact in the progression of COVID-19 cases, hospitalization, and deaths by combining time series, machine learning and epidemiological models with data retrieved from the SUS and seroprevalence provided by the Dados do Bem app.