EPICOVID 19-BR 2: national expanded access seroprevalence survey

COVID-19 is a disease produced by the SARS-CoV-2 virus that is part of a broad family of viruses that can cause illness in humans and animals. This virus has spread rapidly around the world, which has led the World Health Organization to classify this disease as an international health emergency and, subsequently, to declare a COVID-19 pandemic. The number of cases reaches the figure of 19,200,000. cases reported in the world, but these data do not reflect the real prevalence of COVID-19 in the population, since they are susceptible to a series of limitations, given that people with more severe symptoms are more likely to perform the test, whereas asymptomatic individuals or those with mild illness have a low chance of undergoing the test. Brazil is the second most affected country, with more than 2,900,000 reported cases and 98,493 deaths. In Brazil, the State of São Paulo is the most affected state with more than 598,000 cases and 24,500 reported deaths. Therefore, to identify the magnitude of the problem, it is necessary to have data that allow a good estimate of the prevalence of the infection in the population, its dynamic behavior and the dispersion pattern of the disease in the various waves existing in the Brazilian population. Seroprevalence surveys are powerful tools for measuring the exposure of a given population to an epidemic infectious agent. The main objectives of this study are to estimate the seroprevalence of SARS-CoV-2 in Brazil, to evaluate symptoms and to analyze the speed of expansion of the infection in a territorial sample that covers a significant part of the Brazilian population. This study is part of and represents the continuation of the study EPICOVID 19-BR - Evolution of the prevalence of COVID-19 infection in Brazil: a population-based study, coordinated by the Federal University of Pelotas and with 6 sequential phases foreseen. However, for administrative reasons, the original funding foreseen for the study was interrupted after the completion of the third phase. At the moment, it was decided, also for financial administrative issues, to divide the sequence of the study into two parallel projects. 1) corresponds to phase 4 of the original study, with the same design and methodology and will be conducted by the same team from UFPEL with financial support from the institution Todos Pela Saúde, according to attached documents; 2) corresponds to the proposal presented in this project for funding in the form of Thematic Research Project, submitted to FAPESP. It will be conducted in a single phase, with a methodology similar to that of the original study, but with a significant methodological difference, which will be sampled all residents of the selected households. This will represent an approximately 4-fold increase in the sample size originally calculated. There are several advantages of this new design: 1) greater precision in prevalence estimates; 2) possibility of estimating differences in exposure by age and municipality / region with greater precision. Check more precisely the patterns of dispersion of the epidemic wave in the national territory; 3) finally, with the best epidemiological knowledge of the dynamics of the epidemic in our country, allowing the development of optimized control strategies. The following text describes the methodology of the original study with appropriate insertions and modifications for the description of the work that it proposes to finance through the FAPESP Theme. (AU)