(WALTHAM, Mass.) -- Antiretroviral drugs given as treatment of HIV/AIDS could prevent HIV infection if taken before exposure to the virus, according to a new study published Tuesday in the New England Journal of Medicine.
The study offered the first indication of an oral method to prevent the spread of HIV among those at high risk.
"We've known for some time that correct and consistent condom use is the best way to prevent transmission," said Dr. Anthony Fauci, Director of the National Institute of Allergy and Infectious Diseases, an arm of the National Institutes of Health in Bethesda, Maryland, which partly funded the study. "We have had frustration all along in behavior modification programs -- getting people to use condoms, getting people to reduce the number of sexual partners."
Surpisingly, study participants who used the new oral method, called pre-exposure prophylaxis, or PrEP, reported a higher compliance with other HIV prevention methods such as condom use, and also reported a decrease in the number of sexual partners, Fauci said.
The study, called iPrEx, which began in June 2007, followed 2,499 men and transgendered women from six countries, including the U.S., who engaged in sexual intercourse with other men and were categorized as high risk for HIV infection. Participants were randomized to either receive a combination antiretroviral drug commonly known as Truvada or a placebo.
Participants assigned to Truvada who reported taking the pills about half of the time they were prescribed had about a 50 percent lower risk of HIV infection. Those who reported taking the medication about 90 percent of the time had a 73 percent lower risk of infection.
Although the study was limited to one type of high-risk group, other PrEP studies are looking at other groups at risk for transmission, including heterosexual couples and intravenous drug users. Researchers also plan to conduct a follow up study to iPrEx beginning 2011.
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