The first large Brazilian study on the extent of infection by the new coronavirus estimates that the number of infected people in the country is at least seven times greater than that officially registered. The last report, from this Thursday, shows 30,425 confirmed cases, and 1,924 deaths due to COVID-19.

Coordinated by the Epidemiology Center of the Federal University of Pelotas (UFPel), the study, whose model was imported from China, aims to test 33,250 people from 133 Brazilian cities through a rapid test that detects the presence of IgM (most recently infected) and IgC (oldest infection) antibodies. The idea is that the sampling is sufficient to indicate the number of real cases in the country.

The pilot project of the study collected samples in nine cities in the state of Rio Grande do Sul last weekend. From it, the researchers estimate that the number of infected people can be at least seven times greater than that officially registered.

About 0.05% of the more than 11 million inhabitants of the state of Rio Grande do Sul may have been contaminated, that is, 5,650. In the state government accounts, which usually test only the most symptomatic or severe cases of the disease, Rio Grande do Sul would have 747 cases.

The national phase of the study begins next week. According to the epidemiologist and rector of Ufpel, Pedro Hallal, with these data, it is possible to estimate how many infections are asymptomatic or “subclinical”, and have data for more accurate calculations of lethality (percentage of deaths among those infected), the scientist told the newspaper Folha de S.Paulo.