[Prevalence and associated factors of syphilis among adolescents men who have sex with men in two Brazilian capitals].

The objective was to estimate the prevalence and identify factors associated with syphilis among adolescent men who have sex with men (AMSM). This cross-sectional, multicentric study recruited 199 AMSM aged 15 to 19 through the respondent-driven sampling (RDS) method between December 2020 and August 2022, using questionnaires and rapid tests in Fortaleza and São Paulo. Estimates were calculated using STATA 17, considering a 95% confidence interval after weighting the data in each city and combining adolescents from both capitals into a single database. A multivariate model was constructed based on bivariate analyses with p < 0.20. The prevalence of syphilis was 10.9% (95%CI: 6.7-17.3). In the final model, higher odds of syphilis infection were associated with AMSM having received money for sex (PR 2.9; 95%CI: 1.1-7.3), having taken a rapid HIV test before the study (PR 2.6; 95%CI: 1.0-6.7), and having used illicit drugs in the past three months (PR 4.4; 95% CI: 1.2-15.4). The results show a high prevalence of syphilis among AMSM, highlighting the high vulnerability of these to HIV and other STIs. They reinforce the importance of developing and implementing public policies aimed at AMSM to reduce their vulnerability.