Associations between intravaginal practices and incidence of sexually transmitted infections and bacterial vaginosis among women enrolled in the dapivirine vaginal ring trial (The Ring Study) in southwestern Uganda: a retrospective secondary analysis.

OBJECTIVES: We assessed associations between intravaginal practices (IVPs) and the incidence of sexually transmitted infections (STIs) and bacterial vaginosis (BV) among women using the dapivirine vaginal ring (DVR) or placebo vaginal ring in southwestern Uganda. METHODS: This was a retrospective secondary analysis of data collected from women at risk of HIV infection recruited into the Ring Study. The latter evaluated the safety and efficacy of the DVR between 2013 and 2016. At baseline, a behavioural questionnaire was administered to obtain information on sexual activity and IVP (exposure) defined as; insertion inside the vagina of any items aimed at cleaning the vagina for any reason before, during or after sex other than practices to manage menses. Each participant self-inserted the DVR/placebo and replaced it every 4 weeks for 2 years. Outcomes were diagnosis of STIs, that is, Chlamydia trachomatis, Neisseria gonorrhoea, Trichomonas vaginalis (TV), HIV and BV. The incidence rate of STI/BV was estimated, overall, by IVP and trial arm in single-event-per-participant and multiple-event-per-participant analyses. RESULTS: Of the 197 women enrolled, 66 (33.5%) were <25 years of age. Overall, 93 (47.2%) practised at least one form of IVP. During the follow-up, 172 (87.3%) women were diagnosed with an STI/BV at least once. The majority had TV (73.6%, n=145). Overall rate of STI/BV was 51.9/100 person-years, 95% CI 44.7 to 60.3 (IVP: yes, 51.0 (40.8-63.8) vs no, 52.6 (43.0-64.4)). IVPs were not statistically significantly associated with rate of individual STIs/BV. Similar results were observed when the analyses were conducted separately for each trial arm. CONCLUSIONS: IVP was not associated with risk of STIs/BV in the Ring Study. TRIAL REGISTRATION NUMBER: NCT01539226.