Circumcision Protects Insertive MSM Partners

July 21, 2009

By Tim Horn

Circumcision may protect men who have sex with men (MSM) against HIV transmission via insertive anal intercourse, according to a cohort study conducted in Soweto, South Africa, and reported Monday, July 20, at the Fifth International AIDS Society (IAS) Conference on HIV Pathogenesis, Treatment and Prevention in Cape Town.

Three clinical trials conducted to date, randomizing heterosexual men to immediate or delayed circumcision, have found that circumcision lowers the risk of HIV acquisition by roughly two thirds. Until recently, it wasn’t known if the same benefit extends to men who engage in unprotected insertive anal sex with other men.

The Soweto Men’s Study, reported at IAS by Tim Lane, PhD, MPH, of the University of California at San Francisco and his colleagues, was a non-randomized cohort evaluation involving 378 MSM. Participants reported their sexual behavior with their last five partners, including positioning during anal intercourse (insertive, receptive or both) with men. Circumcision was self-reported, and HIV status was determined through rapid antibody testing.  

HIV prevalence stood at 13.2 percent, and 76.4 percent of the men reported engaging only in insertive anal intercourse. About 36 percent of the men participating in the cohort were circumcised.

In the analysis conducted by Lane’s group, the risk of infection among uncircumcised MSM reporting exclusive insertive anal intercourse with male partners was roughly 4.5 times higher than among circumcised men who reported exclusive insertive anal intercourse.

Lane’s group believes 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. To further explore this suggestion, however, a randomized clinical trial—much like those that have enrolled heterosexual men engaging exclusively in insertive vaginal sex—is necessary. But Lane also warns that the acceptability and ethical implications of male circumcision in MSM populations should be assessed before initiating such clinical trials.

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Previous Comments:

xavier, Johannesburg, 2009-07-24 20:53:55
I think that the assumption that there is a high degree of sexual role segregation in MSM communities in Soweto to be a bit problematic. I am curious to know what evidence the researcher relied on to conclude that 76% of the men had insertive anal intercourse only, and one wonders how representative of a group of MSM this was.

Mike Arnold, Nicholasville, 2009-07-23 00:43:22
I must agree Frank, seems ironic today the US still has the highest rate of circumcision of any industrialized country. Yet still has the highest rate of HIV of any industrialized country.

Frank OHara, , 2009-07-21 20:55:35
This study directly conflicts with four previous studies carried out in Australia, New Zealand, The US and Great Britian that showed no benefit from male circumcision. How is it that this study found such a marked difference? With the falling infant male circumcision rate in The US, a raft of these studies has been coming out with breathless press releases ad infinitum. I predicted more than 10 years ago that there would be a lashback and my prediction is becoming true.