(New York)  Although studies in Africa have shown that circumcision can lower the spread of HIV among heterosexuals, it may not do much to prevent infections among gay and bisexual men in Western countries, a new study suggests.

A number of studies in African nations have found that circumcised heterosexual men were up to 60 percent less likely than uncircumcised men to contract HIV during the study periods.

But it is unclear whether circumcision could have an impact on HIV transmission in the U.S. or other Western countries, where much of the transmission is among men who have sex with men. There has so far been no good evidence that circumcision lowers HIV risk among these men.

In the new study, researchers at the U.S. Centers for Disease Control and Prevention (CDC) looked at HIV infection rates among nearly 4,900 men in the U.S., Canada and the Netherlands who took part in a clinical trial of an HIV vaccine.

Read the full article on reutershealth.com.