The study's independent Data Safety and Monitoring Board met Dec. 12 to review the interim data. Based on the board's review, the National Institutes of Health halted the trial and recommended that all men enrolled in the study who remain uncircumcised be offered circumcision.
"Circumcision is now a proven, effective prevention strategy to reduce HIV infections in men," said Robert Bailey, professor of epidemiology in the UIC School of Public Health and principal investigator of the study.
The clinical trial, funded by the National Institute of Allergy and Infectious Diseases and the Canadian Institute of Health Research, enrolled 2,784 HIV negative, uncircumcised men between 18 and 24 years old in Kisumu, Kenya.
Half the men were randomly assigned to circumcision, half remained uncircumcised. All men enrolled in the study received free HIV testing and counseling, medical care, tests and treatment for sexually transmitted infections, condoms and behavioral risk counseling for 24 months.
Study results show that 22 of the 1,393 circumcised men in the study contracted HIV, compared to 47 of the 1,391 uncircumcised men. In other words, circumcised men had 53 percent fewer HIV infections than uncircumcised men.
Until now, public health organizations have not supported circumcision as a method of HIV prevention due to a lack of randomized controlled trials.
"With these findings, the evidence is now available for donor and normative agencies, like WHO and UNAIDS, to actively promote circumcision in a safe context and along with other HIV prevention strategies," Bailey said.
"Circumcision cannot be a stand-alone intervention. It has to be integrated with all the other things that we do to prevent new HIV infections, such as treating sexual transmitted diseases and providing condoms and behavioral counseling," Bailey said. "We can't expect to just cut off a foreskin and have the guy go on his merry way without additional tools to fight against getting infected."
Opponents of circumcision have speculated that circumcised men may feel they are not at risk of contracting HIV and may be more likely to engage in risky behavior. The Kenya study suggests that circumcision did not increase risky behavior among circumcised or uncircumcised men, according to Bailey.
"Both uncircumcised and circumcised men are reducing their sexual risk behavior," he said, "which indicates that our counseling is doing some good."
The study also evaluated the safety of circumcision in a community health clinic with specially trained practitioners. There were no severe or lasting complications from circumcision. However, 1.7 percent of surgeries resulted in mild complications, such as bleeding or infection.
Bailey said that promoting circumcision in Africa must be done in conjunction with proper technical training and medical tools, equipment and supplies necessary to perform large numbers of circumcisions safely.
"Already, there are large numbers of boys and young men who are seeking circumcision in areas of Africa where men are not traditionally circumcised," he said. "The danger is that unqualified practitioners will fill a niche by providing circumcision, but with much higher complication rates."
An estimated 30 million people in Africa are infected with HIV/AIDS and more than 90 percent of HIV infections in adults result from heterosexual intercourse. In Kisumu, the third-largest city in Kenya, an estimated 26 percent of uncircumcised men are HIV infected by age 25.
"This study will likely not have a large impact on the incidence of HIV/AIDS in the United States or Europe where heterosexual transm ission of HIV is low compared with areas like sub-Saharan Africa and parts of Asia," Bailey said. "However, there are other proven health benefits of circumcision, including better hygiene, fewer urinary tract infections, and less risk of cervical cancer in the partners of circumcised men."
The armamentarium of HIV prevention strategies is very small, according to Bailey. The only other strategy proven effective is the use of antiretroviral drugs to reduce transmission from mother to child.
If a significant proportion of men in a population get circumcised, it will have an enormous impact on preventing HIV infection in men, as well as reducing infections in women, Bailey said.