“…For instance, the latest study, published in 2016, looked at PrEP coverage of 25%, 50%, 75% and 100% in comparison with no PrEP use. 25 As to adherence, Kessler et al 24 and Schneider et al 26 considered adherence of 63% and 75%, respectively, while Carnegie et al used adherence cut-offs of zero, two and four pills per week, with a corresponding per-contact risk reduction of 0%, 75% and 90%, respectively.…”