Figure 1.

Impact of partial adherence in randomized controlled trials. The measured efficacy (Eff_Measured = 1 - RR) of an HIV prevention intervention as a function of mean adherence level in a trial with actual biological efficacy per sexual act of Eff_Int = 25%, 50% or 75% respectively. Panel A shows the results assuming vaginal intercourse as the mode of transmission and panel B shows the results assuming receptive anal intercourse as the mode of transmission.