Seroprevalence of SARS-CoV-2 in southwest Goiás, Brazil, 2020: a population-based cross-sectional serological study

Aim: The COVID-19 pandemic has been causing significant socioeconomic and health implications worldwide. We aimed to perform a population-based serological survey of SARS-CoV-2 in Quirinópolis, Goiás and to relate the infection to sociodemographic and epidemiological aspects. Methods: Systematic sampling and active search in the community was conducted using a rapid detection kit for specific IgG and IgM. Three collection phases occurred between September and October 2020. Results: In total, 557 volunteers participated in the study. The general seroprevalence rate was 8.1%, with one-off prevalence of 10.4%, 6.7% and 6.8% in each of the three phases. There was a predominance of results for IgG antibodies (88.9%). The bivariate analysis revealed that age < 19 years (OR = 5.0; 95%CI: 2.10-11.90; P = 0.0003), search for medical care (OR = 2.21; 95%CI: 1.10-4.31; P = 0.03), families of 3-4 residents (OR = 2.34; 95%CI: 1.085.05; P = 0.03) and the presence of symptoms (OR = 3.59; 95%CI: 1.92-6.78; P < 0.001) were associated with antibody detection. The symptoms related to the detection of antibodies were mainly fever (OR = 10.49; 95%CI: Page 32 Costa et al. One Health Implement Res 2021;1:31-42 https://dx.doi.org/10.20517/ohir.2021.05 4.52-23.93; P < 0.001) and abnormalities in taste (OR = 13.57; 95%CI: 6.15-29.84; P < 0.001) and smell (OR = 13.30; 95%CI: 5.36-32.99; P < 0.001). Conclusion: The high seroprevalence and predominance of IgG antibodies indicated intense circulation of the virus. These data suggest late application of protective measures, as well as population behaviour that favours viral dissemination. In this aspect, young people < 19 years of age were important, possibly due to greater exposure. The majority detection of mild symptoms was a reflection of the active search in the community.