Social Network Organization, Structure, and Patterns of Influence Within a Community of Transgender Women in Lima, Peru: Implications for Biomedical HIV Prevention.

Understanding social network structures can contribute to the introduction of new HIV prevention strategies with socially marginalized populations like transgender women (TW). We conducted 20 semi-structured interviews and four focus groups (n = 32) with TW from selected social networks in Lima, Peru between May and July, 2015. Participants described layers of social influence from diverse actors in their social networks. The majority identified a close relative as their primary social support, with whom they confided secrets but avoided issues of transgender identity, sexuality, and sex work. Participants described close circles of TW friends with whom they shared information about gender identity, body modification, and sexual partners, but avoided issues like HIV. Community leadership included political leaders (who advocated for transgender rights) as well as social leaders (who introduced TW to hormone therapy, body modification, and commercial sex). Detailed analysis of TW social networks can contribute to implementation and acceptability of new HIV prevention technologies.

Sampling methodologies for epidemiologic surveillance of men who have sex with men and transgender women in Latin America: an empiric comparison of convenience sampling, time space sampling, and respondent driven sampling.

Alternatives to convenience sampling (CS) are needed for HIV/STI surveillance of most-at-risk populations in Latin America. We compared CS, time space sampling (TSS), and respondent driven sampling (RDS) for recruitment of men who have sex with men (MSM) and transgender women (TW) in Lima, Peru. During concurrent 60-day periods from June-August, 2011, we recruited MSM/TW for epidemiologic surveillance using CS, TSS, and RDS. A total of 748 participants were recruited through CS, 233 through TSS, and 127 through RDS. The TSS sample included the largest proportion of TW (30.7 %) and the lowest percentage of subjects who had previously participated in HIV/STI research (14.9 %). The prevalence of newly diagnosed HIV infection, according to participants' self-reported previous HIV diagnosis, was highest among TSS recruits (17.9 %) compared with RDS (12.6 %) and CS (10.2 %). TSS identified diverse populations of MSM/TW with higher prevalences of HIV/STIs not accessed by other methods.