Self-reported symptoms and seroprevalence against SARS-CoV-2 in the population of Mato Grosso: a household-based survey in 2020

OBJECTIVE: This study aimed to analyze the association between self-reported symptoms and seroprevalence against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the population of Mato Grosso. METHODS: A household-based survey was conducted on 4,206 adults from 10 municipalities of Mato Grosso, in the Brazilian Midwest, who were selected by cluster sampling in three stages. Questionnaires were applied between September and October 2020, and chemiluminescence was used for the quantitative determination of immunoglobulin G (IgG) antibodies against the S1 and S2 proteins of SARS-CoV-2. RESULTS: Approximately half (47.0%) of individuals with SARS-CoV-2 antibodies (12.5%) reported having no symptoms. The most prevalent symptoms among individuals with antibodies were body pain (37.0%), fever (32.9%), and smell and taste change (28.7%). The search for a basic health unit was predominant (45.0%) as the first service, and only 5.3% reported being hospitalized. CONCLUSION: A high proportion of asymptomatic cases of coronavirus disease 2019 (COVID-19) was identified in the general population, even among older adults and individuals with comorbidities.