Published online: 8 February 2006
Since the late 1980s, anecdotal evidence has suggested that circumcision can make men less likely to catch HIV from infected partners. The inner lining of the male foreskin can hold nine times more virus than the outer layers of the penis, and is the main entry point for HIV. Some doctors have suggested that cutting off the virus's gateway to the body could dramatically curb infection rates in men.
Now, researchers from the Johns Hopkins Medical Institutions in Baltimore, Maryland, say that it might also benefit women. They say that women with circumcised partners are 30% less likely to become infected, because they are less exposed to the virus.
Ronald Gray led the project, which studied the medical records of more than 300 Ugandan couples from 1994 to 2001. At the beginning, all the men involved were HIV positive, whereas all the women were HIV negative. Of the men, 44 were circumcised and 299 were not. The medical records show that the average annual rate of female HIV infection was 6.6% if they had circumcised partners, compared with 10.3% if the men were uncircumcised.
This suggests that the circumcision of young males in the general African population could have protective effects for both men and women, the team says. They present their conclusions today at the 2006 Conference on Retroviruses and Opportunistic Infections in Denver, Colorado.
Although the study may provide a promising lead for public-health researchers, its findings will have to be confirmed by full medical trials before circumcision can be recommended for all men. "There are all sorts of issues about the quality of this information," warns Jimmy Volmink, director of the South African Medical Research Council's Cochrane Centre in Tygerberg. "It is not a trial, it is a review of medical records," he says, and a statistical review of medical records such as this does not account for factors such as hygienic or sexual practices.
"The strength of a clinical trial is that you can be relatively sure the group is balanced and there are no other factors intervening," says Volmink.
Preliminary findings from the Ugandan review spurred researchers to instigate just such a clinical trial: this involves circumcising half of the 5,000 men in the study and then monitoring rates of HIV infection in the men and their partners. The trial is due to end in 2007.
Trials of male circumcision and HIV in Kenya and South Africa have not monitored its effect on women, because of the difficulty of linking and tracking two people, says Steven Reynolds, part of the Johns Hopkins team.
In 2005, French and South African researchers called an early halt to a trial held in Orange Farm near Johannesburg, because outcomes were so favourable (see 'Caution on circumcision cuts South Africa's AIDS researchers'). Officials considered it unethical to continue after uncircumcised men were shown to be 60% more likely to become infected than circumcised men.
But the results of this trial are still questioned by some AIDS researchers. "In trials, numbers of participants jump around quite a lot and we don't have a final result for this one," says Volmink. "It is prudent to await results before making policy decisions."
Even if the benefits of circumcision can be proved, it may be difficult to persuade some to accept it as standard practice. And public-health officials should be aware that a sudden rise in circumcisions that are not medically supervised could even lead to an increase in infections, adds Volmink.