By David March
Johns Hopkins Medicine

A statistical review of the past medical files of more than 300 couples in Uganda in which the female partner was HIV negative and the male was HIV positive provides solid documentation of the protective effects of male circumcision in reducing the risk of infection among women. Male circumcision also reduced rates of trichomonas and bacterial vaginosis in female partners. The study is believed to be the first to demonstrate the benefits to female partners of male circumcision.

Specifically, male circumcision reduced by 30 percent the likelihood that the female partner would become infected with the virus that causes AIDS, with 299 women contracting HIV from uncircumcised partners and only 44 women becoming infected by circumcised men. Similar reductions in risk were observed for the other two kinds of infection but not for other common STDs, including human papillomavirus, syphilis, gonorrhea and chlamydia.

The study was led by Johns Hopkins researchers Ronald Gray, professor in the School of Public Health’s Department of Population and Family Health Sciences, and Steven Reynolds, assistant professor of medicine in the School of Medicine and scientific director with the NIAID/NIH International Centers for Excellence in Research Program, in Uganda.

According to Gray and Reynolds, the findings support efforts to assess male circumcision as an effective means of preventing HIV infection. Circumcision is a practice common in North America and among Jews southern Africa, Europe or Asia.

The couples in the study come from the Rakai cohort, a population of roughly 12,000 in Uganda whom researchers are monitoring to see how HIV infection spreads. The researchers based their findings on extensive interviews with each participant and annual checkups and blood tests.

The findings confirm what has been noticed anecdotally in Africa, where regions in which circumcision is common have lower rates of HIV infection than those without. And the results confirm what was first reported in summer 2005 from a clinical trial conducted in South Africa about the protective effects of circumcision on HIV-negative men who have sex with HIVpositive women.

According to researchers, circumcision’s effects come from the nature of the foreskin’s inner lining, or mucosa, whose cells bind to the virus more easily and have roughly nine times more virus in them than the outer layer of the foreskin. Removal of the foreskin, they say, may simply reduce the susceptibility factor, or degree of exposure to HIV, for the sexual partner.

Thomas C. Quinn, professor of infectious diseases at Johns Hopkins and a senior investigator at the National Institute of Allergy and Infectious Diseases, presented an overview of this trial, plus two others presently under way, as part of a plenary discussion on circumcision and HIV at the 2006 Conference on Retroviruses and Opportunistic Infections, held last week in Denver. But, he says, “We will have to wait for the ongoing two trials before drawing conclusive recommendations about circumcision for all men, and whether or not the benefits apply to transmission from females to males only, or to females from men as well. However, early indications are dramatic and, if proven, one case of HIV disease could be prevented through circumcising anywhere from 15 to 60 males.” This talk and others by Hopkins faculty can be viewed at www.retroconference.org/2006.