SARS-CoV-2 seroprevalence among adults in the cities of Mariana and Ouro Preto, Minas Gerais, Brazil

Abstract

Background and Objectives: At the beginning of the COVID-19 pandemic, the absence of a national protocol for epidemiological surveillance and control hindered the understanding of the true prevalence of COVID-19 in Brazil. This study aimed to estimate the anti-SARS-CoV-2 antibodies prevalence and describe the serological profile according to socioeconomic, geographic, and health characteristics in Mariana and Ouro Preto municipalities, Minas Gerais. Methods:A cross-sectional population-based serological survey was conducted with 1,762 adults from October to December 2020. A qualitative immunochromatographic rapid test assessed infection; georeferencing and statistical inference analyses were performed. Results: The infection prevalence was 5.2%. Multivariate analysis revealed that lower per capita family income (≤ 0.5 minimum wage) (OR: 0.27; 95% CI: 0.13–0.59), higher density of occupants per room (≥ 0.5) (OR: 0.47; 95% CI: 0.23–0.97), and previous contact with suspected or confirmed cases of COVID-19 (OR: 2.58; 95% CI: 1.16–5.73) were significantly associated with seropositivity. Seropositive individuals reported higher frequencies of fatigue (14.8%), dyspnea (9.3%), ageusia (9.3%), and anosmia (8.8%), in addition to lower educational performance (p=0.024), lower per capita family income (p=0.018), and a greater number of comorbidities (p=0.041). A heterogenous geographic distribution was observed, with concentrations in census sectors with average incomes of one to three minimum wages. Conclusion: The study highlights a heterogeneous distribution of SARS-CoV-2 infections, with seropositive individuals predominantly coming from lower socioeconomic segments and presenting greater health vulnerabilities. These findings emphasize the need for targeted public health strategies and interventions to improve disease surveillance and mitigate health disparities in similar contexts.