Over the past two years, it has become increasingly clear that adult circumcision helps protect men from acquiring HIV. As previously reported recent studies have shown that circumcision reduced the rate of HIV infection by as much as 60% in high-prevalence countries in Africa.

At the XVII International AIDS Conference last week in Mexico City, researchers who conducted one of the pivotal African studies in Kisumu, Kenya, reported follow-up data showing that the benefits appear to be long-lasting.

As reported in the February 24, 2007 issue of The Lancet, the Kisumu trial included 2874 young men aged 18-24 years who expressed an interest in circumcision and were randomly assigned to undergo the procedure immediately or to be added to a waiting list for delayed circumcision. The trial was stopped ahead of schedule in December 2006 after interim results at 24 months showed a 53% to 60% reduction in HIV acquisition in the circumcised group, and all participants were offered circumcision regardless of initial assignment.

In last week's presentation, Robert Bailey from the University of Illinois at Chicago School of Public Health reported data from up to 42 months (median 30 months) of follow-up. As of May 2008, 1545 men consented to extended follow-up (767 in the circumcision group and 778 controls). During this period, 42% of the men in the delayed circumcision control group elected to undergo circumcision; the age and number of sexual partners were similar for men who did and did not undergo circumcision.

Results

• During the extended follow-up, there were 5 additional infections in the circumcised group compared with 17 in the uncircumcised group.

• In total, there were 27 HIV total seroconversions among the circumcised men compared with 62 among the uncircumcised men over the entire study period.

• The 42 month cumulative HIV incidence rate was 2.6% among circumcised men and 7.4% among uncircumcised men, representing a protective effect of 70%.

• In an analysis based on initial assignment to the immediate or delayed circumcision group, the protective effect was 65%.

"The protective effect of circumcision against HIV acquisition among sexually active men seen over 24 months of follow-up is sustained, and possibly strengthened, to 42 months," the investigators concluded. "Results support expeditious provision of safe, affordable circumcision services as part of comprehensive HIV prevention strategies."

The study is planned to continue through 5 years to determine whether the protective effect lasts even longer.

University of Illinois at Chicago School of Public Health, Chicago, IL; RTI International, Research Triangle Park, NC; UNIM Clinic and University of Manitoba, Winnipeg, Canada; University of Washington School of Medicine, Seattle, WA; National Institute of Allergy and Infectious Disease, Division of AIDS, Bethesda, MD; University of Nairobi, Nairobi, Kenya.

8/15/08

References

RC Bailey, S Moses, CB Parker, and others. The protective effect of male circumcision is sustained for at least 42 months: results from the Kisumu, Kenya Trial. XVII International AIDS Conference (AIDS 2008). Mexico City. August 3-8, 2008. (Abstract)

Other citations

RC Bailey, S Moses, CB Parker, and others. Male Circumcision for HIV prevention in young men in Kismu, Kenya: a randomised controlled trial. The Lancet 369(9562): 643-656. February 24, 2007.