In a massive medical trial on three continents, doctors are testing a controversial pill that could temporarily boost immunity against HIV before a person is even exposed to the virus. If the pill works safely, doctors must then address whether such a drug, if made widely available, could actually worsen the AIDS epidemic.
The pre-exposure pill undergoing testing seems promising, since HIV drugs taken within days after exposure to the virus have been shown to reduce the risk of infection by 80 percent. But public health officials debate whether people at high risk for the virus, such as men who have sex with men, would be more likely to set aside the use of condoms to instead rely on a drug regimen that doesn't provide full protection against the disease, which is spread by contact with the blood or semen of an infected person.
Dennis, a 47-year-old gay man from Atlanta, is one of the test subjects for the new pill. He calls himself "blessed" for escaping the HIV epidemic that hit many of his friends in the 1980s. But his HIV-negative status hasn't stopped him from having sex with infected partners.
"If you just say that you're not going to have sex with anyone who's HIV positive , here you're eliminating a whole bunch of wonderful people," said Dennis, who asked that his last name be withheld. "How shallow would that be?"
He was recruited for the clinical trial for PreP, or pre-exposure prophylaxis for HIV prevention, with a drug called tenofovir.
"I was eager to take it," said Dennis. Since he was already using condoms, he said, "It couldn't hurt. I'll know in June if I was taking the real McCoy, or if it was the fake pill."
Soon after he started the trial, he noticed the doctors were trying to study his behavior as much as the drug's side effects. Each time he went for a monthly checkup, HIV test and counseling, Dennis said the director of the study, Lynwood Miller at the AIDS Research Consortium of Atlanta, kept asking him about his sex practices.
"I don't think I was any more promiscuous just because I was taking the drug," he said. "I didn't put myself at risk just to test the drug. I'm not that crazy."
But doctors worry that others who are at risk for HIV might well put aside their condoms for unprotected sex -- relying on the partial protection of the drug.
The stakes are high in terms of human lives and health costs. Statistics released by the Centers for Disease Control and Prevention in mid-2008 show that in 2006 some 56,000 new cases of HIV infections were reported in the United States, and 1.1 million people have HIV, 25 percent of whom don't know they have it. Worldwide, some 33 million people are infected and 25 million have died of the disease.
Doctors in the trial say they are acutely aware of the possibility the drug may be misused.
"There have been reports that people may be using PreP out in the community even before it was in trial," said Dr. Albert Liu, director of HIV prevention intervention studies at the San Francisco Department of Public Health.
So Liu and his colleagues decided to investigate. They did studies in San Francisco, traveled to large "circuit parties" in Palm Springs, Calif., and San Diego, where gay and bisexual men go to dance and have sex on weekends.