Objectives: To describe: (a) the prevalence and individual and network characteristics of group sex events (GSEs) and GSE attendees; and (b) HIV/sexually transmitted infection (STI) discordance among respondents who said they went to a GSE together.
Methods and design: In a sociometric network study of risk partners (defined as sexual partners, persons with whom respondents attended a GSE, or drug injection partners) in Brooklyn, NY, we recruited a high-risk sample of 465 adults. Respondents reported on GSE attendance, the characteristics of GSEs, and their own and others' behaviors at GSEs. Sera and urines were collected, and STI prevalence was assayed.
Results: Of the 465 participants, 36% had attended a GSE in the last year, 26% had sex during the most recent of these GSEs, and 13% had unprotected sex there. Certain subgroups (hard drug users, men who have sex with men, women who have sex with women, and sex workers) were more likely to attend and more likely to engage in risk behaviors at these events. Among 90 GSE dyads, in which at least 1 partner named the other as someone with whom they attended a GSE in the previous 3 months, STI/HIV discordance was common [herpes simplex virus (HSV-2): 45% of dyads, HIV: 12% of dyads, and chlamydia: 21% of dyads]. Many GSEs had 10 or more participants, and multiple partnerships at GSEs were common. High attendance rates at GSEs among members of large networks may increase community vulnerability to STI/HIV, particularly because network data show that almost all members ofa large sociometric risk network either had sex with a GSE attendee or had sex with someone who had sex with a GSE attended.
Conclusions: Self-reported GSE attendance and participation were common among this high-risk sample. STI/HIV discordance among GSE attendees was high, highlighting the potential transmission risk associated with GSEs. Research on sexual behaviors should incorporate measures of GSE behaviors as standard research protocol. Interventions should be developed to reduce transmission at GSEs.