HIV Treatment Dramatically Prevents Heterosexual Transmission

Jon is a staff writer for Science.

A multicountry study has found that HIV-infected people who start antiretroviral (ARV) treatment at earlier stages of the disease lowered their risk of transmitting the virus to their sexual partners by 96%. The results have major policy implications and “add yet again to the armamentarium of data that indicate the multifaceted benefits of early treatment,” said Anthony Fauci, head of the U.S. National Institute of Allergy and Infectious Diseases (NIAID), which sponsored the 6-year study.

NIAID, which spent $73 million on the trial, had planned to fund it for another 4 years, but an interim analysis by an independent monitoring group led the institute to pull the plug early and announce the results. Run by the HIV Prevention Trials Network (HPTN) at 13 sites in nine countries, the study recruited 1763 couples (97% heterosexual) in which only one partner was infected with the AIDS virus at the start. None of the HIV-positive people had taken ARVs, and all had CD4 counts that ranged from 350 to 550 per milliliter (normal is above 600). Half the participants received immediate treatment, and the other half did not start ARVs until their CD4 count dropped to 250 or they developed an AIDS-related symptom. Everyone received free condoms, safe sex counseling, and treatment for other sexually transmitted diseases.

The interim analysis found that 39 people had become infected, and 28 cases were linked by genetic tests to their regular partners. Of those 28, all but one had a partner in the group that waited to start treatment. Earlier observational studies had shown a similar impact of ARVs reducing sexual transmission in heterosexual couples, but this was the first to demonstrate the prevention power of the drugs in a randomized, controlled clinical trial. “This applies exclusively to heterosexual couples,” cautioned Mike Cohen, a researcher at the University of North Carolina, Chapel Hill, who headed the so-called HPTN 052 study. Cohen noted that they had hoped to include men who have sex with men in the study, but few volunteered to participate.

Although the finding was largely expected—ARVs, after all, reduce the level of HIV in infected people—the prevention power of the drug was greater than the study designers initially anticipated, and policymakers hope it will have a major impact. “It’s information that is not really taking me by surprise, but it’s a game-changer in the AIDS response,” says Michel Sidibé, who heads the Joint United Nations Programme on HIV/AIDS. Sidibé says the results should help put to rest debates about the worthiness of spending money on ARVs as prevention when only one-third of the 15 million HIV-infected people in the world who need treatment for their own immediate health have access to drugs. “The divorce between treatment and prevention is not real,” he says. “Treatment can reduce the number of new infections, which can increase the value of treatment.”

Current treatment guidelines issued by the World Health Organization call for offering treatment to everyone at CD4 counts of 350 or below. Most guidelines in developed countries recommend starting treatment between 350 and 500, but in reality, people who have health insurance or their own money can start at any CD4 count. Sidibé says he hopes the new results will compel pharmaceutical companies to lower the price of ARVs as the demand for the drugs expands. He also anticipates that new partnerships will form to advocate for increased funding and that the findings will be prominently discussed next month at the United Nations High Level Meeting on AIDS in New York City.

But some HIV/AIDS advocates question whether the world will respond appropriately to this good news. Matthew Kavanagh, director of U.S. advocacy for Health GAP (Global Access Project) in Washington, D.C., notes that the U.S. government’s PEPFAR program—which supplies about half the ARVs to people in developing countries—has no plans to scale up. “It’s crazy to me that we’re hearing out of PEPFAR and other places there is not a strategy to roll this out,” Kavanagh says. “The U.S. could be stepping up and saying, 'We have an amazing finding and let’s galvanize the world around this.' ”

Kavanagh notes that the Global Fund to Fight AIDS, Tuberculosis and Malaria—which provides the other half of HIV treatment for the poor countries—also has far less money than it needs. “If there’s not a renewed emphasis that, at all costs, we have to scale up treatment for both life-saving and prevention benefits, we’re going to see a reversal of fortunes and we’ re not going to be able to make use of what the science is telling us,” he says.

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