Sexual health specialists have long focused on circumcision as a potential safeguard against acquiring HIV. In fact, a 2006 clinical trial funded by the National Institutes of Health (NIH) found that medical circumcision reduced female-to-male transmission rates by 48% to 60% in two trials in Rakai, Uganda and Kisumu, Kenya. So it was during the course of an additional trial in Rakai — this one to determine if male-to-female transmission rates were also reduced by the procedure — that researchers decided to test the impact of circumcision on other sexually-transmitted infections.
Among the trial’s participants, all of whom were HIV-negative and in heterosexual married or long-term couples, circumcision reduced the rate of transmission of high-risk human papillomavirus (HPV) in both men and women. All men in the trial underwent the surgery, but some were randomly assigned to have the procedure immediately, while others waited for another 2 years. In the interim, the researchers monitored HPV infection rates in both the men and their partners. Women whose partners had the surgery later had a 28% higher rate of HPV infection than those whose partners were circumcised at the beginning of the study. It’s important to note, however, that while rates of new HPV infection among the women with circumcised partners was 23% lower than that of the non circumcised group, these infections continued to be transmitted. That means that condoms — and the HPV vaccine, such as Cervarix and Gardasil, when available — are still essential prevention methods. (More on Time.com: Daughters Care What their Moms Think, Especially Regarding the HPV Vaccine)
Most of the time HPV clears up on its own, but it can cause genital warts and some high-risk strains (such as those studied here) are the primary cause of cervical cancer. Some strains also increase the risk of head, neck, penile and anal cancers. Reuters reported:
Cervical cancer is the second most common cancer in women worldwide and is expected to kill 328,000 this year, mostly in developing countries.
GlaxoSmithKline and Merck make vaccines against HPV but they are not available to most women in developing countries.
Circumcision removes the foreskin of the penis, which is rich in immune system cells targeted by HIV and perhaps other viruses. Taking off the foreskin likely makes the penis less likely to carry a range of microbes, [Dr. Maria] Wawer’s team [at Johns Hopkins University] said.
“Our findings indicate that male circumcision should now be accepted as an efficacious intervention for reducing the prevalence and incidence of HPV infections in female partners. However, protection is only partial; the promotion of safe sex practices is also important,” wrote Wawer in The Lancet, where the study was published on Jan. 6.