Male circumcision fends off the most common STDs

Male circumcision offers a degree of protection against genital herpes and human papillomavirus infections, scientists report in the March 26 New England Journal of Medicine. Previous research shows circumcision can also protect against HIV, which means the operation can fend off the three most common viral sexually transmitted diseases — all of which are currently incurable.

The new findings, from a study of men and adolescent boys in Uganda, show that circumcision provides only partial protection against these three viruses, and the researchers caution that it should not be considered a full shield.

Nevertheless, that partial benefit could have a huge public health impact, says Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases in Bethesda, Md. For example, herpes ulcers make a man more susceptible to HIV infection.

“Circumcision not only prevents HIV outright, but also prevents [genital herpes] that is associated with an increased likelihood of acquisition of HIV,” he says. “You get a double-positive here.” In Kenya, four out of five people infected with HIV are also infected with genital herpes, says Robert Bailey, an epidemiologist at the University of Illinois at Chicago.

Meanwhile, the new study and a recent report from South Africa show that male circumcision may benefit women, too. Compared with uncircumcised men, those who were circumcised as part of either of the clinical trials were one-third less likely to be infected with one of the dangerous types of human papillomavirus, or HPV, that can cause cervical cancer when passed on to women.

A third study team, based in Kenya, will also report findings on circumcision’s effect against STDs in the coming months. Bailey, a member of the Kenya study team, could not give details but acknowledged that the upcoming results will fall in line with the newly released data.

Earlier studies by all three teams showed male circumcision lessened the risk of acquiring HIV by up to 60 percent.

“I think this trio of trials is certainly a landmark in prevention, not only of HIV but of these other sexually transmitted infections,” says Judith Wasserheit, an infectious disease physician at the University of Washington and the Fred Hutchinson Cancer Research Center, both in Seattle. “These new data really are a game changer.”

The trial in Uganda, supported by the NIAID and the Bill & Melinda Gates Foundation, enrolled 3,393 uncircumcised heterosexual males ranging in age from 15 to 49. None had genital herpes and all wanted to be circumcised. Half were randomly assigned to get circumcised at the start of the trial and the others were designated to undergo the operation after a two-year wait.

After the two years elapsed, circumcised volunteers were one-fourth less likely to have genital herpes and one-third less apt to carry a type of HPV that causes cervical cancer, compared with the still-uncircumcised males. HPV comes in many varieties. When all HPV types were assessed, including those causing genital warts, the circumcised volunteers were still nearly one-third less likely to carry one of the types, says study coauthor Thomas Quinn, an infectious disease physician at NIAID and Johns Hopkins University in Baltimore. The study did not show protection against syphilis.