Male circumcision reduces risk of genital herpes and HPV infection, but not syphilis

Heterosexual men who undergo medical circumcision can significantly reduce their risk of acquiring two common sexually transmitted infections-herpes simplex virus type 2 (HSV-2), the cause of genital herpes, and human papillomavirus (HPV), which can cause cancer and genital warts, according to a report in the March 26 issue of the New England Journal of Medicine (NEJM). In the study, circumcision had no effect on their risk of becoming infected with the bacterium that causes syphilis, however.

The findings build upon earlier clinical research funded by the National Institute of Allergy and Infectious Disease (NIAID), part of the NIH, which found that circumcision decreases a man's risk of acquiring HIV infection through heterosexual intercourse by more than 50 percent (http://www3.niaid.nih.gov/news/newsreleases/2006/AMC12_06.htm).

"Medically supervised adult male circumcision is a scientifically proven method for reducing a man's risk of acquiring HIV infection through heterosexual intercourse," says NIAID Director Anthony S. Fauci, M.D. "This new research provides compelling evidence that circumcision can provide some protection against genital herpes and human papillomavirus infections as well."

The study was conducted by scientists at the Rakai Health Sciences Program in Uganda in collaboration with researchers at the Johns Hopkins University Bloomberg School of Public Health in Baltimore, Makerere University in Kampala, Uganda, and NIAID's Division of Intramural Research. The collaborators examined samples from two parallel clinical trials in Rakai that successfully proved male circumcision as an HIV prevention method and also assessed the surgical procedure's ability to prevent other sexually transmitted infections, including syphilis and HSV-2. These infections cause genital ulcers and are associated with an increased risk of HIV acquisition. The research team also assessed circumcision's effect on HPV infections, which can cause anal, cervical and penile cancers and genital warts.

The two trials, one funded by NIAID and the other by the Bill & Melinda Gates Foundation, enrolled 3,393 uncircumcised men between the ages of 15 and 49 who initially tested negative for both HIV and HSV-2. The men were assigned at random to one of two study groups: 1,684 received immediate circumcision performed by trained medical professionals in an outpatient setting (intervention group); and 1,709 received medical circumcision after a delay of 24 months (control group). The researchers evaluated the volunteers at six, 12 and 24 months for HSV-2 and syphilis infection. Additionally, a subgroup of 697 volunteers (352 participants in the intervention group; 345 in the control group) was evaluated for HPV infection at enrollment and at 24 months.

In analyzing the effect of circumcision on HSV-2 acquisition across both studies, the researchers found that the cumulative probability of HSV-2 infection was significantly lower among those volunteers who received immediate circumcision (7.8 percent) than among those in the control group who were circumcised at 24 months (10.3 percent). Overall, the researchers found that medically supervised circumcision reduced the men's risk of HSV-2 infection by 28 percent.