French and South African researchers have found that male circumcision reduces by about 70% a man's risk of contracting HIV through intercourse with an infected woman. Nothing besides abstinence and safer sex has been proven to reduce the sexual spread of HIV. Worldwide, heterosexual sex has been the major route of HIV transmission for many years.

The circumcision study's findings were so dramatic that the data and safety monitoring board overseeing the research halted the study in February, roughly nine months before completion, on the ground that it would be immoral to proceed without offering the uncircumcised control group an opportunity to undergo the procedure. Circumcision directly affected men's chances of infection; women would benefit indirectly if circumcision reduced the chances of their partners being HIV-positive.

Field researchers are aware of the study's basic findings, but experts haven't evaluated them because the study has yet to be published. The British journal The Lancet declined to publish the study, for reasons unrelated to data and scientific content, according to people familiar with the matter. In accordance with policy, the journal's officials refused to comment on why the study was turned down.

That an independent board ordered the study halted is considered by some to be a strong sign that the science is sound. Bertran Auvert, the French lead researcher, is expected to present the findings later this month at an International AIDS Society conference in Brazil.

The research was conducted with more than 3,000 HIV-negative South African men ages 18-24. Half were randomly assigned circumcision while half remained uncircumcised as controls. After following all the men for a year, researchers found that for every 10 uncircumcised men who contracted HIV, only about three circumcised men got the virus.

Stopping trials is common when an intervention is clearly shown to be effective. The result of the trial may spark discussion of whether to halt or modify two other major circumcision-HIV studies underway in Kenya and Uganda, funded by the National Institutes of Health. Ronald Gray, lead researcher on the Uganda trial, says it would be unwise to stop the Kenya and Uganda trials because "medicine has been burned in the past when policy is based on a single trial."

The new study suggests that in countries where male circumcision is uncommon and heterosexual HIV rates are high or rapidly rising, circumcision could be a powerful way of reducing the virus's spread. However, researchers warn of potential pitfalls, stressing that HIV transmission could rise if men abandon safer sex practices because they think circumcision completely protects them.

"It will not take very much of an increase in risk behavior to overcome the benefit from circumcision," says Carolyn Williams, an American researcher involved in the Kenya trial. AIDS experts say circumcision would have to be accompanied by intensive counseling.

Furthermore, experts worry that circumcision performed under unsanitary conditions could lead to dangerous complications. There also is the question of whether men from African cultures that do not practice circumcision would consent to the procedure to reduce their risk of contracting HIV.

[This summary provided by the CDC National Center for HIV, STD, and TB Prevention | Mark Schoofs, Sarah Lueck, and Michael M. Phillips | July 5, 2005 | The Wall Street Journal]