Efficacy: The trial found that a once-daily pill containing tenofovir plus emtricitabine (brand name Truvada) provided an average of 44 percent additional protection to men who have sex with men (MSM) who also received comprehensive prevention services which included monthly HIV testing, condom provision, counseling, and management of other sexually transmitted infections (95 percent CI 15 to 63 percent).
Consistent use of PrEP: The level of protection shown varied widely depending on how consistently participants used PrEP. Among those whose data (based on self-reports, bottles dispensed, and pill counts) indicates use on 90 percent or more days, HIV risk was reduced by 73 percent (95 percent CI 41 to 88 percent), while among those whose adherence by the same measure was less than 90 percent, HIV risk was reduced by only 21 percent (95 percent CI, from a 52 percent reduction to a 31 percent increase).
Risk behavior: Risk behavior among participants declined overall during the trial both in terms of decreases in the number of sexual partners and increases in condom use, likely as a result of the intensive risk reduction counseling provided as part of the trial.
*Findings from CDC Fact Sheet, Nov. 23, 2010
