Topical penile microbicide use by men to prevent recurrent bacterial vaginosis in sex partners: a randomized clinical trial

Abstract

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.

Figure 1

Study profile for the randomized controlled trial. Numerator for follow-up is those either still in follow-up and at risk, or who already had BV during follow-up.

Figure 2

Survival until first detection of BV by Nugent Score ≥ 7 after the baseline visit (Kaplan-Meier estimates), by randomization arm (p=0.04, log rank test). Visits were scheduled at 1 week, 1 month, and 2 months following initiation of the treatment regimen. In the intervention arm there were 72 failures during 117 person-months at risk (61.5% incidence of BV per month in those at risk). In the control arm there were 58 failures during 132.5 person-months at risk (43.8% incidence of BV per month in those at risk). The number at risk for both study arms for a given follow-up visit is given on the first day a subject in either arm returned for that follow-up visit. For the 1 week visit, this was 5 days, for the 1 month visit, 24 days, for the 2 month visit, 55 days.