Male circumcision and HIV.

Although several studies suggest that circumcised men are less likely than uncircumcised men to become infected with HIV, evidence is insufficient to recommend male circumcision to prevent HIV, a systematic review of the research has concluded.

The review, published in the third issue of The Cochrane Library in 2003, is the most comprehensive analysis to date of studies on male circumcision and HIV. The reviewers found no published or unpublished results from completed randomized controlled trials on the effect of male circumcision on HIV acquisition. Instead, they assessed 34 observational studies that examined the relationship between male circumcision and HIV, usually as part of an investigation of various risk factors for HIV.

The studies that were reviewed found strong epidemiological evidence of an association between male circumcision and HIV prevention, particularly among groups at high risk of HIV infection. Twenty-seven of the 34 studies found that male circumcision protected men from acquiring HIV, and results from 17 of those 27 studies were statistically significant. However, the differences observed among circumcised and uncircumcised men in these studies could be explained by other factors that might confound the results, the Cochrane reviewers report. Many of the studies, for example, did not adequately account for the effects of important factors that could affect HIV risk, such as religion and sexual practices.

Four randomized controlled studies are under way in sub-Saharan Africa to test the effect of male circumcision on HIV acquisition. The results of these studies, expected in 2005 or 2006, "will need to be carefully considered before circumcision is implemented as a public health intervention for prevention of sexually transmitted HIV," the reviewers concluded.

All four trials will recruit uncircumcised men. Those who agree to participate will be randomly assigned to be circumcised or to be part of an uncircumcised comparison group. Three of the studies--one in Kisumu in western Kenya that is recruiting 2,676 men, one in South Africa's Gauteng Province involving some 3,500 men, and another in Rakai, Uganda, that is enrolling 5,000 men--will determine whether circumcision protects men from acquiring HIV. A related study in Rakai will enroll 2,900 men, including men who are HIV positive, and will follow some 6,000 women in the community to assess the effect of male circumcision on HIV transmission to female partners as well as male acquisition of the virus.