JOHANNESBURG -- Men who are circumcised have a dramatically lower rate of HIV infection than those who are not, according to new studies in Africa and India, suggesting that the ancient surgical procedure may play a role in helping prevent the spread of the deadly virus.
One unpublished household survey in Kenya has shown that uncircumcised men have an HIV rate that is 11 times greater, while a second study in India has found uncircumcised men have a seven times higher rate of infection. Other studies showed that Zambia and Ethiopia had lower rates of HIV infection in areas of the countries where circumcision was more common. Researchers have suspected a link between circumcision and HIV prevention for more than 15 years. In the United States, studies have shown that high circumcision rates have had a protective benefit for heterosexual Americans. But most specialists have not recommended the procedure because they believed that other factors such as religious and cultural beliefs might explain the link.
The recent Kenya data, however, have given new impetus among some AIDS experts to focus more attention on the issue. The Kenya study was completed by the Demographic and Health Surveys, a Maryland-based independent group that conducts detailed surveys around the world.
Leaders in at least two African countries, Swaziland and Zambia, have said that, while they want more definitive evidence linking circumcision with preventing HIV, they say the epidemiological studies have startled them.
"Watch this. There could be some breakthroughs coming out of this," Derek von Wissell, director of Swaziland's National Emergency Response Council on HIV/AIDS, said in a telephone interview from Mbabane, the capital. "If the evidence comes through, we could really look at this as a preventive measure. It's almost as effective as a vaccine. The effect would be massive."
World Health Organization officials, however, warn that ongoing clinical trials need to be completed before deciding whether circumcision should be recommended as a prevention tool against the spread of HIV. Those studies, underway in Kenya, Uganda, and South Africa, will be completed in one to three years.
"The numbers are striking, but we have to make sure that's really the effect from circumcision," said Kevin R. O'Reilly, a WHO specialist on the treatment and prevention of HIV and AIDS. "We don't know if the elevenfold increase we're seeing in Kenya is related to circumcision alone or differences in sex patterns, religious patterns, and other things."
O'Reilly said that even if male circumcision was shown to help prevent HIV, "the question is, what do you do with that information? . . . The preference for or against circumcision among different groups is a fairly strongly-held conviction. It has a lot to do with group identify. In tribal circumstances, it might be us vs. them -- we circumcise and they don't."
He also expressed concern that some men who believe circumcision prevents HIV might abandon other safe-sex precautions. "We have a long history in HIV/AIDS prevention learning time. . . . There is no magic bullet."
Circumcision, the removal of the foreskin of the penis, is one of the world's oldest and most common surgical procedures. It is part of a ritual practiced for thousands of years by Jews and Muslims. Many Christians and people of other faiths also are circumcised, and the procedure is most often performed on newborn babies.
According to a review of scientific research by the US Agency for International Development, the inner surface of the foreskin absorbs HIV up to nine times more efficiently than female cervical tissue.
Circumcision is already known to reduce a man's risk of penile cancer. A study of 393 men from a clinic in Tuscon, published last month in the journal Sexually Transmitted Diseases, also found that circumcision may reduce the risk of cervical cancer in female sexual partners. That confirmed an earlier five-country study published in the New England Journal of Medicine.
In Africa, the countries with the highest rates of HIV infection are in the far south, which have low circumcision rates. Countries in West Africa and the island nation of Madagascar have lower HIV prevalence and very high male circumcision rates.
For years, most AIDS experts have said that the lower rates were largely attributable to large Muslim populations, which generally had more conservative sexual behaviors than Christian communities.
Conservative religious beliefs and sexual behavior apparently do not explain some situations for low HIV prevalence. In Madagascar, where nearly 100 percent of boys are circumcised by puberty, about 10 percent of the population is Muslim, 45 percent Christian, and 45 percent follow traditional beliefs. The island also has high rates of sexually transmitted infections, which can increase risk for HIV transmission. And yet the island's HIV prevalence is estimated at 1.4 percent.
"It's an intriguing question why HIV prevalence varies so dramatically across different parts of Africa as well as parts of Asia," Daniel Halperin, a USAID expert on HIV prevention, said in an interview from Washington. "The main, although not the only, factor explaining this appears to be male circumcision."
But Halperin, who has been one of the most passionate supporters for more research on male circumcision and health, said that USAID would not recommend mass circumcision campaigns to lower HIV risk. "It really needs to come from the Africans themselves," he said. "They may be the ones to implement it on their own or ask for donor assistance. Maybe that's when things will change."
In Zambia, USAID has just begun funding its first training sessions for health workers to perform voluntary circumcision surgery. Emmanuel Oladipo Otolorin, a regional HIV/AIDS adviser for Johns Hopkins University's international public health institute, said that African countries should start training health workers now to perform safe circumcisions, instead of waiting for further data.
"One cannot ignore these observational studies," Otolorin said by telephone from Lusaka. "Now many men are going to traditional circumcisers and some are coming out with terrible complications and infections. So why don't we strengthen sites that are already providing facilities on a limited scale?"
In September, Otolorin posted a small note outside a clinic in Lusaka advertising free circumcisions. He said more than 50 men showed up. Only a few mentioned that they wanted to be circumcised as a prevention for HIV; most said they believed circumcision would either improve their hygiene or sexual satisfaction.
"But can you imagine if we now go out and say, 'Oh, male circumcision is associated with a lower risk of HIV?' " Otolorin asked. "All the young men would be queuing up to have this done. We have to be cautious about this. We know it is not an absolute protection. But this is an intervention we cannot ignore."
John Donnelly can be reached at donnelly@globe.com