While studies in Africa have shown that circumcised heterosexual men are as much as 60 percent less likely than their uncircumcised peers to contract HIV from female partners, a new three-year study from the Centers for Disease Control and Prevention (CDC) finds that circumcision does not necessarily prevent transmission among men who have sex with men (MSM) in Western countries, Reuters reports.

In the study, which was published in the journal AIDS, the CDC examined HIV infection rates among nearly 4,900 men in the United States, Canada and the Netherlands who took part in an HIV vaccine clinical trial. They found no evidence that circumcision affected HIV transmission risk. The agency is considering whether to recommend circumcision to high-risk heterosexual men and whether there is suitable evidence to recommend circumcision for MSM.

According to Deborah A. Gust, PhD, MPH, and her colleagues at the CDC, many HIV-positive people in Western, developed countries are on HIV regimens that reduce the risk of transmission. Furthermore, circumcision would not affect HIV risk from receptive anal sex, which she says would outweigh any protective value of circumcision during insertive sex.

Researchers note that, just as other CDC scientists have concluded, circumcision would likely have a “limited” impact on HIV transmission in the United States.