Lower Risk of HIV Among Circumcised MSM: Results From the Soweto Men's Study

Male circumcision has been found to reduce female-to-male HIV transmission through vaginal sex in randomized controlled trials. However, one recent meta-analysis of observational data found insufficient evidence of a protective effect with men who have sex with men (MSM), while noting the lack of data from high-prevalence settings. In the Soweto Men's Study, researchers examined the association between insertive anal intercourse and HIV infection among MSM in a peri-urban South African community.

Researchers enrolled 378 MSM through respondent-driven sampling and surveyed the men about their sexual behavior with their last five partners. Participants were asked whether their sexual role with male partners was insertive, receptive or both. Circumcision status was self-reported, and HIV status was determined by rapid antibody testing. Results were adjusted for network size and recruitment patterns and reported with 95 percent confidence intervals (CI).

Overall, 36.4 percent of MSM were circumcised; HIV prevalence was 13.2 percent (12.4-13.9 percent); and 76.4 percent reported exclusive insertive anal intercourse (75.4-77.3 percent). Among those exclusively insertive, 88.1 percent (87.1-89.1 percent) also reported having female partners. In multivariable analysis, the odds of infection among uncircumcised MSM reporting exclusive insertive anal intercourse with male partners were significantly higher than among insertive circumcised MSM (adjusted odds ratio 4.5; 95 percent CI 3.1-6.7).

"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," the researchers concluded. "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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