Increased vulnerability to SARS-CoV-2 infection among indigenous peoples living in the urban area of Manaus (preprint)

ABSTRACT

Background The COVID-19 pandemic threatens indigenous peoples living in suburban areas of large Brazilian cities and has thus far intensified their pre-existing socio-economic inequalities. This study evaluated the epidemiological situation of SARS-CoV-2 infection among residents of the biggest urban multiethnic indigenous community of the Amazonas state, Brazil. Methods Blood samples of 280 indigenous people who live in the urban community known as Parque das Tribos, which is located in the surrounding area of Manaus, were tested for the presence of anti- SARS-CoV-2 IgA or IgG antibodies using an enzyme-linked immunosorbent assay. An epidemiological standardized interviewer-administered questionnaire was applied to assess the risk factors and sociodemographic information of the study population. Results We found a total positivity rate of 64.64% (95% CI 59.01-70.28) for SARS-CoV-2 infection. IgA and IgG were detected in 55.71% (95% CI 49.89-61.54) and 60.71% (95% CI 54.98-66.45) of the individuals tested, respectively. From the total number (n=280), 80.11% of positive individuals (95%; CI 74.24-85.98) were positive for both IgA and IgG Abs. All individuals with COVID-19-related symptoms on the day of blood collection (n=11) were positive for IgG, while IgA was detected in 84.61% (n=55) of individuals who had presented symptoms several weeks before the blood collection. Individuals aged 30-39 were more susceptible to SARS-CoV-2 infection (prevalence ratio [PR] 0.77; 95% CI 0.58-1.03; p=0.033). People whose main source of information on COVID-19 was religious leaders or friends showed higher susceptibility to infection (PR 1.22; 95% CI 1.00-1.49; p=0.040). In addition, individuals who left home more frequently were at higher risk of infection (PR 1.22; 95% CI 1.00-1.49; p=0.048). Five or more individuals per household increased almost 5-fold the risk of virus transmission (Odds ratio [OR] 2.56; 95% CI; 1.09-6.01; p=0.019). Over 95% of the study population had no access to clean water and/or sanitation. Conclusions The disproportionate dissemination of SARS-CoV-2 infection observed in the Parque das Tribos urban indigenous community might be driven by typical cultural behavior and socioeconomic inequalities. Despite the pandemic threat, this population is not being targeted by public policies and appears to be chronically invisible to the Brazilian authorities.