More Evidence on the Protective Effects of Male Circumcision

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Summary and Comment

More Evidence on the Protective Effects of Male Circumcision

Two large trials confirm that male circumcision can reduce HIV incidence among men by at least 50%.

In December 2006, two large randomized trials of male circumcision were halted when the Data and Safety Monitoring Boards concluded that circumcision dramatically lowered the incidence of HIV infection among men (ACC Dec 22 2006). Now, investigators have published the 24-month results of both studies.

In the first study, 2784 HIV-negative men in Kenya (age range, 18–24) were randomized to circumcision or to a wait list. During follow-up, seroconversion occurred among 22 men in the circumcision group and 47 in the control group, yielding 2-year incidence rates of 2.1% and 4.2%, respectively. In an intent-to-treat analysis, circumcision was associated with a 53% reduction in risk for HIV infection. In an as-treated analysis, the magnitude of risk reduction was even greater (60%). Adverse events (most commonly, bleeding, infection, and disruption in healing) occurred in 1.5% of circumcised men. About 95% of all circumcised men adhered to the 30-day post-circumcision period of abstinence. At 24 months, both groups had significant reductions in high-risk sexual behavior.

Similar results were seen in the second study, which involved 4996 HIV-negative men in Uganda (age range, 15–49). The incidence of HIV infection per 100 person-years was 0.66 in the circumcision group, compared with 1.33 in the control group. Circumcision was associated with a 51% reduction in incidence in an intent-to-treat analysis and a 55% reduction in incidence in an as-treated analysis. Eight percent of the intervention group experienced adverse events, with most rated as mild or moderate. At 6 months, the circumcision group reported more condom use than did the control group, but by 24 months, the groups had similar patterns of risk behavior.

Comment: These two trials, together with a similar one in South Africa (PLoS Med 2005; 2:e298), indicate that male circumcision can lower HIV incidence among men by at least 50%. Importantly, the intervention groups in these studies did not display measurable increases in high-risk behavior, as previously feared. However, both studies included intensive counseling, education, and access to condoms, and such interventions might not be available to the same extent outside the research setting. The rate of serious complications was low in both studies but also underscores the need for appropriate medical follow-up and availability of further care when necessary. For male circumcision to have the greatest possible effect, it must be part of a comprehensive prevention package and be provided with the highest achievable level of safety. Results are eagerly awaited from long-term follow-up of the circumcised men in these trials and from a parallel study in Uganda of HIV-infected men and the rate of transmission to their partners after circumcision.

— Rebeca Plank, MD

Dr. Plank is an Infectious Disease Fellow at Brigham and Women’s Hospital in Boston.

Published in AIDS Clinical Care March 19, 2007