Model predictions of the cumulative fraction of infections prevented over a period of 10 years (FC(10)) for vaginal microbicides in clinical trials with minimum individual-level efficacy (MIE) set at 20% (light gray boxes), 10% (white boxes), and 0% (dark gray boxes). Various observed efficacies are illustrated: A) 33%, B) and D) 50%, C) 75%. Box plots show 5th, 25th, 50th, 75th, and 95th percentiles of the predictions generated by 10,000 simulations per scenario. Scenarios Sc1-Sc8 are defined in Table 2.