Characteristics of the 11 PrEP trials appraised.

Legend: Registration code: as per the National Institute of Health trials registry. Sponsors: BMGF = Bill and Melinda Gates Foundation; CDC = Centers for Disease Control and Prevention (United States of America); Gilead = Gilead Sciences Incorporation; CONRAD = University of Eastern Virginia's CONtraceptive Research & Development program; FHI = Family Health International; NIH = National Institutes of Health (United States of America); USAID = United States Aid for International Development; UW = University of Washington. Enrolled: number in brackets represent target sample sizes; other numbers are actual sample sizes reported. Population: homo = homosexual; hetero = heterosexual. Countries: USA = United States of America.