Effect of consistent condom use on 6-month prevalence of bacterial vaginosis varies by baseline BV status

Objectives: Bacterial vaginosis (BV) is a condition characterized by a disturbed vaginal ecosystem which fluctuates in response to extrinsic and intrinsic factors. BV recurrence is common. To explore whether consistent condom use was associated with BV occurrence or recurrence, we compared the effect of condom use on BV prevalence after 6 months, among women with and without BV at baseline. Methods: We used data from a randomized controlled trial, conducted among female sex workers in Madagascar during 2000-2001, that assessed the impact of adding clinic-based counselling to peer education on sexual risk behaviour and sexually transmitted infection incidence. BV was diagnosed at two time points (baseline and 6 months) according to modified Amsel criteria. Consistent condom users were women reporting no unprotected sex acts with clients in the past month or non-paying partners in the past year. Adjusted prevalence ratios (PRs) and 95% confidence intervals (CIs) were calculated using multivariable regression models. Results: At baseline, 563 (56%) women had BV. Of those, 360 (72%) had BV at 6 months, compared to 158 (39%) without BV at baseline. The adjusted 6-month PR for BV comparing consistent to inconsistent condom users was 0.99 (95% CI: 0.85-1.13) among women with BV at baseline and 0.57 (95% CI: 0.30-0.94) among women without BV at baseline. Conclusions: Consistent condom use was associated with reduced BV prevalence at 6 months for women who were BV-negative at baseline, but had no effect among women who were BV-positive at baseline. Male condoms appeared to protect against BV occurrence, but not BV recurrence.