Men who are circumcised have about half the risk of acquiring HIV infection through vaginal intercourse as do men who are uncircumcised. That finding during interim analysis prompted the NIH to stop two trials underway in Uganda and Kenya prior to their completion. The announcement came during a news conference on Dec. 13.
The findings were no surprise. Researchers have known for many years that rates of HIV infection in Africa generally are lower among populations where most of the men are circumcised. However, because most of the men who are circumcised are Muslim, they did not know whether it was because of the circumcision or because of other social or cultural practices associated with that religion.
The first randomized controlled trial to test circumcision as a prevention intervention was carried out in South Africa and was stopped in 2005 when interim analysis found that it reduced female-to-male transmission of HIV by at least 60 percent. Those results were so dramatic that it would have been unethical to delay circumcision for those volunteers who had been randomized to receive it at the conclusion of the trial.
Additional trials on circumcision were underway in Uganda and Kenya and were allowed to continue with periodic monitoring of the results by a data safety monitoring board. In December, the board determined that there was a reduction in risk of acquiring HIV of 48 and 53 respectively and advised that the trials be terminated early.
'These results indicate that adult male circumcision could be an important addition to an HIV prevention strategy for men,' said Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases at NIH. 'However, it is not completely protective and must be seen as a powerful addition to, not a replacement for, other HIV prevention methods.'
The World Health Organization ( WHO ) began to develop activities around male circumcision after results of the South African trial became known last year, said Kevin De Cock, director of WHO's department of HIV/AIDS. They will offer guidance and training to countries that choose to make circumcision more widely available.
However, he warned that circumcision must be carried out under proper medical conditions. There is risk of common infection with any medical procedure, and improperly sterilized tools carry the added risk of HIV infection.
Circumcision is common in the United States, reaching a peak of about 85 percent of males born in 1965 but declining thereafter. Part of the decline is because medical associations decided that the procedure carries no medical benefit and have dropped their support for it. As a result some insurance providers no longer provide reimbursement.
Whites are more likely to be circumcised than are people of color in the U.S. Given the recent evidence of the protective effect of circumcision from the trials in Africa, this may help to explain part of the reason why rates of HIV infection are higher among Blacks and Hispanics than whites.
The results of these trials are likely to lead to reconsideration of what, if any, role circumcisions should play in the prevention of HIV transmission within different societies and groups of persons who are at risk.