Demographic and behavioral contextual risk groups among men who have sex with men participating in a phase 3 HIV vaccine efficacy trial: implications for HIV prevention and behavioral/biomedical intervention trials.

Recent outbreaks of syphilis and gonorrhea coupled with reported increases in HIV-risk behavior among men who have sex with men (MSM) have raised concerns about a potential resurgence of HIV among MSM. These concerns have led some to suggest the need for a paradigm shift in how HIV-prevention programs are designed and implemented. In this analysis, baseline demographic, sexual partnership, and substance use information was used to identify contextual-risk groups among 5,095 HIV-seronegative MSM enrolled in a 36-month phase 3 HIV vaccine efficacy trial across 61 sites primarily in North America.