Topical Penile Microbicide Use by Men to Prevent Recurrent Bacterial Vaginosis in Sex Partners: A Randomized Clinical Trial

Background: Bacterial vaginosis (BV) recurs frequently after metronidazole treatment. This randomized, single-masked clinical trial evaluated the efficacy of topical application of 62% ethyl alcohol in emollient gel (gel) to the penis by male partners of women diagnosed with BV for preventing post-treatment BV recurrence. Methods: Among 587 Kenyan women presenting with vulvovaginal symptoms, 236 had BV (vaginal Gram stain Nugent score >= 7), of whom 223 (94.3%) agreed, along with their partners, to be randomized: 115 to the intervention and 108 to the control arm. In the intervention arm, male partners agreed to apply gel each morning, and before and after sexual intercourse. All couples received counseling, condoms, and syndromic treatment of sexually transmitted infection symptoms. Follow-up visits were scheduled 1 week, 1 month, and 2 months postenrollment, with vaginal Gram stains at every visit and culture for H2O2-producing lactobacilli at the 2-month visit. The primary outcome was time to diagnosis of BV during follow-up. Results: In the primary intent-to-treat analysis, diagnosis of BV was significantly more frequent in the intervention arm (hazard ratio: 1.44, 95% confidence interval: 1.01-2.04). After adjustment for baseline covariates, the hazard ratio was 1.39 (95% confidence interval: 0.98-1.99). At the 2-month visit, prevalences of any vaginal lactobacilli or of H2O2-producing lactobacilli did not differ appreciably in the 2 study arms (P = 0.81 and 0.32, respectively). Conclusion: Daily use of the 62% ethyl alcohol gel by men before and after sex significantly increased persistence or early recurrence of BV in their partners through 2 months after metronidazole treatment. However, no difference was observed in prevalences of vaginal lactobacilli within this same period.