Vaginal Microbicide and Diaphragm Use for Sexually Transmitted Infection Prevention: A Randomized Acceptability and Feasibility Study Among High-Risk Women in Madagascar

Background: In preparation for a randomized controlled trial (RCT), we conducted a pilot RCT of the acceptability and feasibility of diaphragms and candidate vaginal microbicide for sexually transmitted infection prevention among high-risk women in Madagascar. Methods: Participants were randomized to four arms: (1) diaphragm (worn continuously) with Acidform™ applied in the dome; (2) diaphragm (worn continuously) with placebo gel hydroxyethylcellulose in the dome; (3) HEC applied intravaginally before sex; (4) Acidform applied intravaginally before sex. All women were given condoms. Participants were followed weekly for 4 weeks. We fit unadjusted negative binomial regression models with robust variance estimators to generate the proportion of sex acts with casual partners where condoms and experimental study products were used. Results: Retention was 98% among 192 participants. Experimental product use with casual partners was high, reported in 85%, 91%, 74%, and 81% of sex acts for women in the Acidform-diaphragm, HEC-diaphragm, HEC-alone, and Acidform-alone arms, respectively. However, the proportion reporting product use during 100% of acts with casual partners over the full follow-up period was much lower: 28% to 29% in the gel-diaphragm arms and 6% to 10% in gel-alone arms. Women used condoms in 62% to 67% of sex acts with casual partners, depending on the randomization arm. Participants found diaphragms easy to insert (97%) and remove (96%). Acidform users (with or without the diaphragm) reported more genitourinary symptoms than users (14% vs. 5% of visits). Conclusions: A sexually transmitted infection prevention RCT of candidate microbicide with and without the diaphragm appears acceptable and feasible in this population.