PREVAIL IV:  Double-Blind Randomized Two-Phase Placebo Controlled Phase II Trial of GS-5734 to Assess the Antiviral Activity, Longer-Term Clearance of Ebola Virus and Safety in Male Ebola Survivors with Evidence of Ebola Virus Persistence in Semen is a blinded, randomized, two‐phase (treatment and longer‐term follow‐up), two‐arm trial of GS‐5734 versus placebo to evaluate the safety, tolerability, antiviral activity, and longer‐term clearance of Ebola virus from male survivors with persistent Ebola virus in semen at screening. Male participants from PREVAIL III with evidence of Ebola viral RNA in their semen are randomized to receive a five-day infusion of GS-5734 or a five-day infusion of placebo. Primary objectives are to compare the antiviral activity of GS-5734 to placebo over 28 days and to compare the treatment groups on detection of Ebola virus RNA in semen over 24 weeks. Enrollment began in Liberia and was expanded into Guinea.