Phase 2B/3 Double-blinded Placebo-controlled

Primary: To determine if intravaginal EVO100 reduces the risk of urogenital Chlamydia trachomatis (CT) infection. Secondary: To determine if intravaginal EVO100 reduces the risk of urogenital Neisseria gonorrhoeae (GC) infection. Exploratory:To determine if EVO100 use rate (subject adherence to instructed use) has an effect on proportion of subjects who experience CT or GC infection during the study intervention period. Primary Outcome Measures: Proportion of subjects who experience urogenital CT infection during the study intervention period (incident infection of CT). Secondary Outcome Measures: Proportion of subjects who experience urogenital GC infection during the study intervention period (incident infection of GC). Exploratory Outcome Measures: * Compliance with EVO100 usage during study (rate of product use adherence). * Sensitivity analyses of the primary parameter (proportion of subjects who experience at least one CT or GC infection during the study intervention period) will be performed for the following: * Subjects with ≥20%, ≥40%, ≥60% and ≥80% product use adherence * Subject Satisfaction * Sexual satisfaction