A new human immunodeficiency virus prevention strategy is making waves in the medical community.

A. David Paltiel, a professor at the School of Public Health, and his team of researchers have published a study showing that the HIV prevention model — called pre-exposure prophylaxis, or PrEP — could reduce an individual’s lifetime HIV infection risk from 44 percent to 25 percent and could increase his or her overall life expectancy by eight-tenths of a year. Despite the study’s results, however, some professionals said they remain skeptical of the PrEP approach. (PrEP is an HIV prevention strategy based on giving antiretroviral drugs to high-risk populations before they contract the disease in order to reduce their risk of infection.)

The study, which simulates the health outcomes of middle-aged homosexual men, also found that if PrEP’s effectiveness is higher than the model estimates, lifetime infection risk would be even more significantly reduced. Namely, if the drug was 90 percent effective instead of the proposed 50 percent, the risk of infection would drop from 44 percent to 5.8 percent.

“If there was a pill that you could take once a day that could prevent HIV infection,” Paltiel asked, “how much would you be willing to pay?”

For logistical and ethical reasons, Paltiel said, the researchers had to resort to a mathematical model to investigate decisions about the disease.

Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, the institute that co-funded Paltiel’s project, said he decided to fund the proposal because of its powerful implications.

“PrEP is a promising area of research that potentially could have significant public health value in preventing HIV infection,” he said.

The study’s assumption that PrEP would be effective in preventing HIV 50 percent of the time is a relatively high figure in the world of chronic disease, said Robert Levine, professor of Internal Medicine at the Yale School of Medicine.

“If you look at the cancer field, 50 percent effectiveness would be something that we truly celebrate,” he said.

But the study has also caused dissent among researchers.

For instance, Levine took issue with PrEP’s proposed cost — $9,000 annually — which he said makes the model an unfeasible option for foreign countries, and particularly for developing nations.

Gregg Gonsalves, a HIV/AIDS activist and student in the Eli Whitney Program, said the study does not take into account the benefits of social education and therapy, which might be a more cost-effective way to combat rising infection rates at this point.

“Right now we have an exploding epidemic among young, black gay men and young gay men more generally, so we desperately need to figure out a way to reduce infections among these young guys,” he said. “PrEP may be one strategy, but dealing with substance use, depression, violence in these men’s lives might also offer a way to reduce their risk.”

Martha Dale SPH ’80, executive director of Leeway, an HIV/AIDS care facility in New Haven, agreed that communities need an aggressive social marketing campaign to make younger people more aware of the risk of contracting the virus.

But Dale said she is not opposed to the possibility of a successful drug-related prevention scheme. “Everything we can do for this population, I think we should do,” she said.

A cure may be a distant reality for HIV/AIDS, which has killed an estimated 25 million people in the past 20 years. As a result, Paltiel’s study is evidence of the focus among clinicians on ways to improve treatment strategies and reduce the side effects and toxicity of HIV drugs, assistant professor of medicine Krystn Wagner said.

“There is no belief right now that a patient who is infected will eradicate the disease,” she said. “So now it’s not only about HIV control, but also about looking at the long-term effects of those drugs and how they interact with other medical conditions.”