June 9, 2000 -- The foreskin of the uncircumcised penis is a welcome mat for HIV, according to a new study. The finding strengthens a growing consensus among public health experts that both infant and adolescent circumcision programs ought to be a major tool in the fight to stop AIDS, especially in countries where HIV is rampant.

The experts warn that circumcision alone does not protect a man from being infected with HIV. It does, however, greatly reduce his odds of being infected.

The new study takes a close look at a surprisingly neglected part of the human anatomy: the penis. Roger V. Short, ScD, professor of obstetrics/gynecology at the University of Melbourne Royal Women's Hospital in Melbourne, Australia, and his colleague Robert Szabo analyzed penis tissues from autopsies of 13 men age 60 to 96 years, seven of whom had been circumcised. They found that the inner surface of the foreskin -- but not any other outside part of the penis -- is rich in a type of cell that carries HIV directly to the T cells, the cells in which the virus replicates itself.

Why has it taken so long for such a relatively simple study to be performed? "When you look at who has studied the anatomy of the male penis, it is almost no one," Short tells WebMD. "First of all, you have a very hard time obtaining the material. We have woefully little information on the human penis, and that is why no one has looked at the cells responsible for the viral uptake."

Szabo and Short found that a relatively hard layer of skin protects the shaft of the penis and the outside of the foreskin. However, the inner surface of the foreskin is not protected. During sex, the foreskin is pulled back down the shaft of the penis and provides a large area of exposure to HIV from an infected partner.

This finding is more than just interesting. Public health experts have been piling up evidence that circumcised men are at far lower risk of contracting HIV -- if they are free of sexually transmitted diseases (STDs) -- than uncircumcised men. One of these scientists has estimated that circumcision, as practiced in 15 African and Asian countries, has prevented some 8 million HIV infections. But these experts say the world's public health agencies have turned a deaf ear to their pleas for action.

Szabo and Short cite a controversial recent study from Uganda looking at couples in which the woman was HIV-positive but the man was HIV negative. During a two and a half year period, the 50 circumcised men did not become HIV-positive, but 40 of the 137 uncircumcised men did become HIV-positive.

Robert C. Bailey, PhD, MPH, professor of epidemiology and anthropology at the School of Public Health at the University of Illinois at Chicago, praises the Szabo and Short findings. "This is one of the pieces of evidence we have been missing to prove that circumcision can have a real biological effect," Bailey tells WebMD.

Bailey and co-author Daniel T. Halperin of the University of California, San Francisco, recently wrote an article putting all the public health evidence together. They show that in comparable areas of the world with comparable sexual practices and comparable standards of living, cultures in which most men are circumcised have significantly fewer AIDS cases than areas where circumcision is uncommon.

"I believe that it is outrageous and in some situations unethical the way this data has been ignored," Bailey says. "Now at least 37 studies show a highly significant effect for circumcision in reducing AIDS incidence. So far the international public health agencies have ignored this. It is past time to do something about this. They ought to be starting to fund and support studies of the acceptability of male circumcision programs in areas of high HIV prevalence. They should be looking into feasibility, training, and resource needs. They also ought to start integrating information on both the risks and benefits of male circumcision into all public health programs."

Both Short and Bailey warn that circumcision would inadvertently increase risk of HIV infection if circumcised men come to believe that they are immune to HIV. The two researchers adamantly insist that circumcision can only be effective in the context of other means of HIV risk reduction.

Interestingly, the two researchers each point to evidence that areas of the world where HIV is highly prevalent would not only support circumcision programs but are already attempting to institute them at the grassroots level.

"I've done surveys in Uganda and western Kenya and asked both men and women about attitudes with regard to circumcision," Bailey says. "They associate circumcision with cleanliness and cleanliness with reduced risk of infection. Many men in areas where they do not traditionally circumcise are seeking information for themselves and their sons. I've seen many clinics springing up to meet this perceived need. Now in South Africa traditional healers are recommending circumcision to prevent recurrent STDs."

Szabo and Short suggest that new medicines that could prevent HIV from entering the penis or the vagina would be a potent new tool in preventing heterosexual HIV transmission to both men and to women.

Ironically, their report is published in the British Medical Journal -- the same medical journal that 50 years ago published an article that brought routine circumcision to an end in the British commonwealth. The article, called "Fate of the Foreskin," set off a furor after blaming infant circumcision for 16 deaths per year.

For more information from WebMD, visit our Diseases and Conditions page on HIV/AIDS, or read our Quick Facts about the disease.

Vital Information:

• Most HIV-positive men were infected through the penis.
• Uncircumcised men are at higher risk of getting AIDS than circumcised men.
• Circumcision alone does not protect a man from catching the AIDS virus.
• Many experts argue that public health agencies should fund circumcision programs in areas hardest hit by the AIDS epidemic.