Male circumcision may not be a universal HIV prevention tool

January 2008

ATLANTA — Male circumcision had no significant effect on HIV prevalence in a U.S. population of men who have sex with men, according to a recent study.

These results were in contrast to recent findings in three trials in Africa indicating that male circumcision could help reduce the risk of heterosexually-acquired HIV among men. Researchers estimated a 60% reduction in HIV risk for circumcised men based on results from these African trials. The trials closed early due to clear efficacy and UNAIDS and WHO began recommending male circumcision as an added method to help prevent the spread of female to male HIV transmission.

But new evidence from studies conducted in the United States, Peru and Australia indicate that male circumcision may not be universally associated with a significant reduction in HIV transmission.

However, the patient populations in the African trials were overwhelmingly heterosexual. The recent studies in the United States, Peru and Australia examined men who have sex with men (MSM).

“There are several key differences in the African trials and in the United States that we have to keep in mind when considering implications for the U.S. population,” said Peter H. Kilmarx, MD, chief of the epidemiology branch in the division of HIV/AIDS prevention at CDC. Findings from the African trials may not necessarily be transferred to the U.S. population for several reasons, Kilmarx said. Major differences in transmission modes, overall HIV prevalence and circumcision rates among adult men in the United States may decrease the impact of circumcision as HIV prevention.

Kilmarx presented an overview on male circumcision and HIV at the 2007 National HIV Prevention Conference, held here recently.

Multiple data sets analyzed

In Kilmarx’s presentation, data were used from 33 states that utilize confidential reporting of HIV and from the National Health and Nutrition Examination Survey (NHANES 1999-2004), which includes self-reported circumcision information on men (n=6,174).

A separate study on minority MSM included black MSM (n=1,154) and Latino MSM (n=1,091) from New York City, Los Angeles and Philadelphia. Participants completed computer-assisted interviews about circumcision status and HIV risk behaviors in the past three months and were tested for HIV.

High-risk heterosexual contact among men accounted for only 11% of HIV infection reported in the surveillance data from 33 states.

“Male circumcision has only shown to promote decreased HIV infection for high risk heterosexual transmission,” Kilmarx said.

Of the total population of men in NHANES, 79% were circumcised. Circumcision rates were 88% among whites, 73% among blacks and 42% among Mexican-Americans. No associations were found between circumcision and sexual behavior.

HIV prevalence is 0.4% in the United States vs. 6% to 19% at African trial sites. Circumcision rates are 70% to 80% in the United States versus 10% to 25% at African trial sites. In Africa, most HIV infections are heterosexually transmitted while in the United States; about half of all HIV cases are characterized as MSM-associated.

For more information:

• Kilmarx PH. Male circumcision and HIV prevention. PL-03.
• Millett GA, Ding H, Lauby J, et al; Circumcision status and HIV infection among black and Latino men who have sex with men in three U.S. cities. C01-4.
• Both presented at: The 2007 National HIV Prevention Conference; Dec. 2-5, 2007; Atlanta.