Sociodemographic and Behavioral Characteristics and HIV and Syphilis Prevalence Among Partners of Transgender Women in Buenos Aires, Argentina.

Transgender women (TW) bear high HIV and syphilis burden, but little is known about their partners (PTW). We conducted a cross-sectional study at a voluntary HIV-testing center in Argentina (June/2023-January/2025). PTW were individuals reporting sex with TW, regardless of other partners' genders. We compared sociodemographic and behavioral characteristics and HIV and syphilis prevalence among PTW, men who have sex with men (MSM), and TW. We included 211 PTW, 1715 MSM, and 152 TW. PTW median age was 30 years and 65% identified as cisgender men. PTW also reported sex with cisgender women (74.9%) and men (53.6%); 22.1% reported transactional sex. HIV and syphilis prevalences in PTW (3.3%, 5.2%) were lower than TW (10.5%, 27.0%) and similar to MSM (6.1%, 8.7%). Syphilis was associated with transactional sex and inversely associated with having sex with cisgender men (p < .05), underscoring the need for tailored prevention strategies for PTW.