Math Models Examine HIV Therapies

Although an estimated 25 million people have died of AIDS since 1981, research conducted by a Harvard Medical School professor suggests that future prospects may not be as bleak.

More than 1.2 million deaths could be prevented in South Africa alone over the next five years by making antiretroviral therapy (ART) more accessible, according to a study released online by the Journal of Infectious Diseases last week.

Using a mathematical model of HIV onset and treatment to simulate hypothetical patients from real data, researchers—led by Rochelle P. Walensky of Mass. General Hospital—projected the number of AIDS-related deaths through 2012 in South Africa under five scenarios.

If current conditions are maintained, 2.4 million South Africans would die from AIDS, but widespread use of ART could cut that number in half.

“The enormity of lives lost is huge,” Walensky said. “Death rates would add up with so many people in need of the [antiretroviral] therapy.”

The one-year survival rate for patients who receive ART is 94 percent, compared to 55 percent for those who go without the treatment, according to the study.

Walensky said that the results of the study highlight the need for continued federal support.

The President’s Emergency Plan for AIDS Relief has supported efforts to increase access to ART in South Africa for the past five years, and reauthorization for this $15 billion plan is due in May.

Kenneth A. Freedberg ’79, who developed the mathematical simulation model in 1994, said that he hopes that the findings will help inform policy decisions.

“We don’t need a vaccine. We don’t need a miracle,” said Freedberg, one of the study’s co-authors. “What’s required is the political will and commitment to save the lives of millions of people.”

OPENING THE GATES

Though Congress has not yet decided whether to reauthorize the AIDS relief plan, Mass. General Hospital received a five-year, $20.5 million grant from the Bill and Melinda Gates Foundation to research the possibility of a vaccine that would limit the replication of the HIV virus in those infected by the virus.

Bruce D. Walker, who is leading the study, estimates that one in every 300 individuals has the genetic makeup to control HIV without medication.

“Basically, there is an extraordinary group of people who have been infected with HIV for up to 30 years and who have never gotten sick,” said Walker, who is the director of the Partners AIDS Research Center at the hospital. “The goal of this project is to figure out why that is and whether we can replicate that in other people.”

Walker and his colleagues founded the International HIV Controllers Study in 2006 with a $2.5 million grant from Mark Schwartz ’76 and Lisa Schwartz, which currently involves more than a dozen countries.

The Schwartzes, who have been major donors to the University’s financial aid and research programs, said that it was a way to “marry [their] interest at Harvard with global health.”

Walker and his team have already recruited 1,000 participants and said they plan to expand the study group to 2,000.

“The reality is that there are [HIV-infected] people walking around right now that have figured out someway to survive without need for medication,” Walker said. “There are answers that could be gleaned from these people that could have incredibly important implications.”

—Staff writer June Q. Wu can be reached at junewu@fas.harvard.edu.

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