Yale scientists have, for the first time, quantified evidence that shows circumcision reduces HIV transmission in African communities.

Kyeen Mesesan MED ’07, an M.D./Ph.D. candidate at the University, developed a mathematical model exploring the beneficial effects of increased adult male circumcision in helping to prevent the spread of HIV.

Mesesan and her team presented their research at the 16th International AIDS Conference in Toronto earlier this summer. Mesesan said the idea of using surgery as a means to fight HIV is a novel idea, and though her model specifically examined the Johannesburg township of Soweto in South Africa, her results are far-reaching.

“These results can be extrapolated to any population of HIV in which the disease is transmitted heterosexually,” she said.

According to a study published in the June 10, 2000, issue of the British Medical Journal, circumcision may decrease the HIV transmission rate because the foreskin — which is surgically removed during circumcision — contains a thin layer of cells with receptors that act as targets for the virus.

Mesesan’s quantitative model simulated the impact of a number of male circumcision programs on the population of Soweto. The team examined HIV prevalence and forecast the total number of people who contracted the disease over a 20-year period after the implementation of five-year circumcision programs. According to the abstract, Mesesan was able to conclude that a program targeting 20 percent of uncircumcised males would prevent 53,000 infections and decrease prevalence to 13 percent.

But despite these optimistic results, Mesesan said the most difficult part of the issue is its sensitive nature — culturally, religiously and politically.

“Understandably, this is a very political and very contentious issue,” she said. “Gender, power, manhood — they’re all defined different ways in different cultures.”

David Paltiel, an associate professor of public health and managerial sciences, said Mesesan’s research is valuable because it shows that even modest increases in the rate of male circumcision will have “enormous health benefits in terms of HIV prevention.”

“It may very well be time to act in terms of widespread implementation of adult male circumcision,” he said. “But the question is the degree to which this can be made culturally effective. Obviously, asking adult males to do something which they might see as mutilation could be difficult.”

But both Mesesan and Paltiel agreed that proper implementation of the new research in HIV-ridden communities can only be done in conjunction with education about sexual risk reduction practices. Mesesan said it would be dangerous and counterproductive if men thought circumcision would lead to immunity from the disease.

Mesesan said that as the HIV epidemic continues to spread, it will be more important to apply her model to other parts of the world as well in order to show the positive effects of circumcision. But she said she recognizes the fact that the hard part of that task will be getting the members of those communities to understand the importance of the issue. Despite the sensitivity towards the issue in some parts of Africa, she said the idea of circumcision is even less acceptable to some populations in India and other South Asian countries.

Benjamin Siegel ’07, an editor at the Yale Journal of Public Health who spent the past two summers in India, said the religious and cultural differences among Hindus, who are not typically circumcised, and Muslims, who are, bring even more complications to the issue in that region, where the two religious groups repeatedly engage in issues of political contention.

Despite a recent study published in the British journal Lancet presenting a significant correlation between being circumcised and becoming HIV positive, actually convincing grown men to adopt the practice is tricky, Siegel said.

“Organizations need to think carefully about the cultural implications that this study has and how to approach something that is this sensitive,” he said.

Even in Africa, Mesesan said, part of the reason for acquiescence may not actually be a change in cultural opinion but the stark reality of the disease’s immediacy — Africans are seeing their friends and neighbors die every day.