[Prevalence of SARS-CoV-2 antibodies in the State of Mato Grosso, Brazil: a population-based survey].

Seroprevalence data provide relevant information on the development and progression of the COVID-19 pandemic. The study aimed to estimate the prevalence of SARS-CoV-2 antibodies in Mato Grosso State, Brazil, and its distribution according to sociodemographic and economic characteristics. This population-based serological survey was conducted in September-October 2020 in individuals 18 years or older in ten municipalities (counties) in the state of Mato Grosso. Interviews and collection of biological samples were conducted in the households, and determination of IgG antibodies to SARS-CoV-2 was performed with chemiluminescence. A total of 4,306 individuals were evaluated, and COVID-19 prevalence was estimated at 12.5% (95%CI: 10.5; 14.7), ranging from 7.4% to 24.3% between municipalities. No significant differences were found in prevalence of infection according to race/color, schooling, or family income, but lower prevalence was seen in individuals with a pensioner living in the same household, who did not receive emergency financial aid, and whose family income had not decreased after social distancing measures during the epidemic. Estimated prevalence of SARS-CoV-2 antibodies in this population-based survey is essential to measure the magnitude of the disease and will back measures to confront and control the pandemic.