A new study concludes that circumcision of HIV positive men does not reduce the risk of transmission of the AIDS virus to women.  But researchers say male circumcision remains a potent weapon against the spread of HIV.

AIDS campaigners were optimistic after a study three years ago among circumcised males in Kenya, Uganda and South Africa which found foreskin removal more than halved men's risk of infection by HIV.

One of the big questions, though, was whether male circumcision could also reduce the risk for women who have intercourse with an HIV-infected man.

The answer, according to a more rigorous trial in Uganda, was no.

 Maria Wawer, a professor with the Department of Population, Family and Reproductive Health at the Bloomberg School of Public Health in Baltimore, Maryland is lead author of the study conducted in Uganda.

"Yes, of course we are disappointed.  But the data are what the data are," she said.

The study involved 922 uncircumcised Ugandan men aged 15-49 who were infected with HIV but who did not show any symptoms.

Half of the group then had circumcision. The other half remained uncircumcised for two years.

The study included uninfected female partners of the men. The couples were counseled about safe sexual practices.

Researchers found that 18 percent of women became infected by their male sexual partners who were circumcised at the start of the study.  That's compared to 12 percent of women who had relations with their uncircumcised husbands for two years until the procedure was performed.

The study was halted because Maria Wawer says investigators essentially saw no difference in the HIV transmission rate between circumcised and uncircumcised men to their uninfected wives.

"As long as couples abstained from sex until full wound healing which is about six weeks then we didn't see any increased risk.  We didn't see decreased risk but we didn't see increased risk," she said.

Wawer says the results of the study - published this week in the journal The Lancet - do not mean that circumcision overall is ineffective in reducing the rate of HIV transmission.  

Wawer says the fact that uncircumcised men may still be at risk of transmitting the virus to women opens the door to education about safe sexual practices," she said. "In other words, if men come in for circumcision, it's a great opportunity to also provide them with HIV health education, to promote and offer condoms, to promote and if at all possible offer counseling.  It's also a way of reaching the partners of men."

Even though the study shows that circumcision appears to offer no benefit to the female partners of men who are infected with HIV, Jared Baeten, a professor of global health at the University of Washington in Seattle, says programs promoting circumcision reduce the spread of the AIDS-virus in entire communities.

"Preventing men from getting HIV in the first place by offering them circumcision, by circumcising them in the first place, will prevent them from getting HIV and will thereby prevent HIV in women," said Baeten.

Researchers say the longer term benefits of male circumcision to women still need to be further studied.