Randomised, controlled, community-level HIV-prevention intervention for sexual-risk behaviour among homosexual men in US cities

Background Community-level interventions may be helpful in population-focused HIV prevention. If members of populations at risk of HIV infection who are popular with other members can be engaged to advocate the benefits of behaviour change to peers, decreases in risk behaviour may be possible. We assessed a community-level intervention to lower the risk of HIV infection, focusing on men patronising gay bars in eight small US cities. Methods We used a randomised community-level field design. Four cities received the intervention and four control cities did not. Participants were men from each city who went to gay bars. Men completed surveys about their sexual behaviour on entering the bars during 3-night periods at baseline and at 1-year follow-up. In the control cities, HIV educational materials were placed in the bars. In the intervention cities, we recruited popular homosexual men in the community and trained them to spread behaviour-change endorsements and recommendations to their peers through conversation. Findings Population-level rates of risk behaviour decreased significantly in the intervention cities compared with the control cities at 1-year follow-up, after exclusion of surveys completed by transients and men with exclusive sexual partners. In a city-level analysis, in the intervention cities we found a reduction in the mean frequency of unprotected anal intercourse during the previous 2 months (baseline 1·68 occasions; follow-up 0·59; p=0·04) and an increase in the mean percentage of occasions of anal intercourse protected by condoms (baseline 44·7%; follow-up 66·8%, p=0·02). Increased numbers of condoms taken from dispensers in intervention-city bars corroborated risk-behaviour self-reports. Interpretation Popular and well-liked members of a community who systematically endorse and recommend risk-reduction behaviour can influence the sexual-risk practices of others in their social networks. Natural styles of communication, such as conversations, brought about population-level changes in risk behaviour.