Pre-exposure prophylaxis study with 129 people split into high/low exposure groups, with each group split into different dosing regimens, showing higher effectivess with more frequent doses.
High-exposure group:
every 7 days dosing: 0 of 20 cases, 100% effective
every 14 days dosing: 1 of 47 cases, 98% effective
every 30 days dosing: 2 of 20 cases, 90% effective
Low-exposure group:
every 14 days dosing: 0 of 21 cases, 100% effective
every 30 days dosing: 1 of 20 cases, 95% effective
Chang et al., 10/31/2020, preprint, 2 authors.