Prevalent bacterial vaginosis infection - a risk factor for incident sexually transmitted infections in women in Durban, South Africa

The association between bacterial vaginosis (BV) and incident sexually transmitted infections (STIs) in a cohort of high-risk women from Durban, South Africa was investigated in this study. We undertook a secondary analysis of the Methods for Improving Reproductive Health in Africa trial that assessed effectiveness of the latex diaphragm and lubricant gel on HIV prevention among women. During study visits, urine specimens were collected for testing for Neisseria gonorrhoeae, Chlamydia trachomatis and Trichomonas vaginalis. The presence of BV was based on vaginal pH and wet mount test assessments. The association between BV and the risk for incident STIs was determined using the Cox proportional hazards model. Prevalence of BV was 31% in a cohort of 435 women tested at baseline. Among these women, BV was significantly associated with incident Trichomonas vaginalis (14.6 per 100 PY, p=0.03) and Chlamydia trachomatis infections (15.8 per 100 PY, p=0.04). BV remained a significant predictor for Trichomonas vaginalis infections even after adjusting for potential confounders such as age and marital status (HR: 1.60, 95% CI: 1.00, 2.57, p=0.04). Our study showed an association between baseline BV infections and incident Trichomonas vaginalis and Chlamydia trachomatis infections. Women with BV infections should be counselled on the use of condoms and the risk of new STIs.