People who took a daily pill to protect against HIV were protected aganist the virus but caught other sexually transmitted diseases through unprotected sex, researchers reported on Monday.
Over a four-year study, only two out of about 500 participants, all at high risk for getting the virus, got infected with HIV, the team reported to the Journal of the American Medical Association.
Each volunteer was given a free supply of Truvada, the pill that's been shown in other studies to protect uninfected people from the virus. It's called pre-exposure prophylaxis or PrEP.
Out of the 437 participants who stuck with the study over four years, most did not stop their high-risk behaviors like anal sex without condoms.