Increase in syphilis among men who have sex with men in Brazil.

This article aims to report the prevalence of syphilis and its associated factors among men who have sex with men (MSM) in Brazil. Respondent-driven sampling was conducted in 12 cities in Brazil between June and December 2016. The target sample size was 350 MSM in each city. Five to six seeds were selected to initiate recruitment and coupons and interviews were conducted online. MSM were considered syphilis-positive if the RST+ and Venereal Disease Research Laboratory results were positive for FTA-Abs. A total of 4176 MSM were recruited. The lifetime prevalence of syphilis was 26.9% (95%CI: 24.0-29.9). The prevalence of active syphilis is 13.2%. Factors associated with active syphilis were as follows: age < 25 years (PR: 1.67, 95%CI: 1.29-2.17), use of mobile dating apps to seek sexual partners (PR: 1.35, 95%CI: 1.01-1.80), and previous diagnosis of sexually transmitted infection (STI) (PR: 1.33, 95%CI: 1.03-1.70). A high prevalence of active syphilis among MSM, particularly young individuals, was found. Approaches to the development of health interventions for MSM STI screening and treatment should be applied.