Daily pill can ward of HIV infection, studies find
Donald G. McNeil Jr., New York Times
Wednesday, July 13, 2011

Two studies released Wednesday add to the growing body of evidence that taking a daily pill containing one or two AIDS drugs can keep an uninfected person from catching HIV.

The studies were the first to show protection in heterosexuals; the only earlier one with similar results involved gay men.

As it becomes clearer that modern antiretroviral drugs can not only treat the disease, but prevent it, pressure is likely to increase on donors to find more money to supply them in African nations now ravaged by HIV and on pharmaceutical manufacturers to sell them cheaply worldwide or release their patents to companies that can.

"This is an extremely exciting day for HIV prevention," said Dr. Kevin Fenton, director of AIDS prevention at the Centers for Disease Control and Prevention. "It's clear we're not going to find a magic pill that prevents it, but this is adding more to the tool kit."

Until a few years ago, condoms and abstinence were alone in that tool kit. Recent studies have added male circumcision, vaginal microbicides, a daily pill for the uninfected and early treatment for the infected.

One of the studies released Wednesday, conducted in Kenya and Uganda by researchers from the University of Washington, showed that participants who took a daily Truvada pill had a 73 percent lower chance of getting infected. The study was done in 4,758 "discordant couples," those in which one partner was infected and the other was not. Partners who took a Viread pill had a 62 percent lower chance.

The second study, done in Botswana by the CDC, found that those taking Truvada had a 63 percent lower chance of infection. The subjects were 1,200 sexually active young adults.

These studies follow a breakthrough study conducted among gay men in San Francisco and published in November. In it, men who took Truvada daily were 44 percent less likely to become infected. But those whose blood samples showed they took it faithfully had 90 percent protection.

The new studies may lead some heterosexual Americans to ask their doctors for Truvada.

Although it will take months to write new CDC guidelines, doctors could use the guidelines written for gay patients after the San Francisco study, with the proviso that Truvada has not been tested in pregnant women, said Dr. Jonathan Mermin, a CDC specialist in AIDS prevention.

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