Prevalence and Vulnerability Factors Associated with HIV and Syphilis in Older People from Subnormal Agglomerate, Brazilian Amazon

Background: This study aimed to estimate the prevalence of HIV and syphilis and associated factors among elderly people from subnormal agglomerations in a city in the Brazilian Amazon. Methods: An observational, cross-sectional study was carried out in a subnormal agglomerate from the Brazilian Amazon. Data collection was conducted from August 2021 to February 2022, using a structured questionnaire. Whole blood samples were collected to perform a rapid test for HIV and syphilis. People aged 50 and over were included in the study, and the sample consisted of 213 participants. The odds ratio was calculated by multiple logistic regression. Results: A total of 203 participants with a mean age of 63.5 years were considered (95% CI: 62.4; 64.6; standard deviation: 8.1; minimum age: 50 years and maximum age: 94 years). The prevalence of either HIV or syphilis was 16.4% (35/213; 95% CI: 0.11; 0.21); syphilis was 15.5% (33/213) and HIV was 1.40% (3/213). One coinfection (0.46%; 1/213) was registered. In the final multiple logistic regression, the elderly with an education level of illiterate/elementary were two times more likely to have a positive rapid test result for HIV or syphilis. Conclusions: Testing for HIV and syphilis identified that STI represented a burden on populations affected by socioeconomic inequality.