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Lower risk of HIV infection among circumcised MSM: results from the Soweto Men's Study
Presented by Tim Lane (United States).
T. Lane1, H.F. Raymond2, S. Dladla3, J. Rasethe3, H. Struthers3, W. McFarland2, J. McIntyre3
1University of California San Francisco, Center for AIDS Prevention Studies, San Francisco, United States, 2San Francisco Department of Public Health, San Francisco, United States, 3Perinatal HIV Research Unit (PHRU), Johannesburg, South Africa
Background: While results of clinical trials have shown that circumcision reduces men's risk of HIV infection through vaginal sex, the effect of circumcision on homosexual transmission through anal intercourse (AI) is less well understood. A recent meta-analysis of available observational data found insufficient evidence of a protective effect with men who have sex with men (MSM), noting that data from high-prevalence, resource-challenged settings are lacking. The Soweto Men's Study explored the association between insertive AI and HIV infection in a peri-urban South African MSM community.
Methods: 378 MSM from Soweto were recruited via respondent-driven sampling (RDS). Participants reported their sexual behavior with their last five partners, including positioning during AI (insertive, receptive, or both) with men. Circumcision status was self-reported, and HIV status was determined though rapid antibody testing. All results have been adjusted for network size and recruitment patterns as recommended by RDS methodology, and are reported with 95% confidence intervals (CI).
Results: HIV prevalence was 13.2% (12.4%-13.9%), and circumcision prevalence was 36.4% (30.0%-44.8%). Exclusive insertive AI (IAI) was reported by 76.4% (75.4%-77.3%); 88.1% (87.1%-89.1%) of these also reported female sexual partners. In multivariable analysis, the odds of infection among uncircumcised MSM reporting exclusive IAI with male partners was significantly higher than among insertive circumcised MSM (AOR 4.5, 95% CI 3.1-6.7).
Conclusions: Circumcision may be effective at reducing HIV transmission between men in high prevalence settings such as Soweto where MSM practice a high degree of sexual role segregation. It may be feasible to conduct a randomized controlled trial of circumcision among MSM in such communities. The acceptability and ethical implications of male circumcision in MSM populations must be assessed prior to initiating clinical trials.
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