Vaginal Probiotics: Results of a Randomized Pilot Trial and Systematic Review
Janneke H.H.M. van de Wijgert1,2, Marijn C. Verwijs1, on behalf of the Rwanda VMB trial group 1 Institute of Infection and Global Health, University of Liverpool, Liverpool, UK; 2 Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands Background: Bacterial vaginosis (BV) is associated with adverse outcomes, and recurrence rates after treatment are high. Many intervention trials have been conducted but few incorporated molecular endpoints. Methods: HIV-negative non-pregnant high-risk Rwandan women were randomized to four groups (n=17 per group) after successful metronidazole treatment of BV or Trichomonas vaginalis (TV): behavioral counseling only (control group) or behavioral counseling plus intermittent use of oral metronidazole, or one of two vaginal probiotics, for two months. Vaginal microbiota (VMB) assessments at all visits included Nugent scoring (7-10 is BV) and 16S rRNA gene qPCR and HiSeq sequencing. Results: No safety concerns were identified for any of the products. During the intervention period, metronidazole users compared to controls had significantly lower BV incidence (1.41/person-year at risk (PY) versus 10.18/PY), and higher mean Lactobacillus concentration and relative abundance, and were less likely to have a dysbiotic VMB type consisting of BV-anaerobes. The two vaginal probiotics also outperformed 'counseling only', albeit with lower effect sizes than metronidazole (e.g. BV incidence rates were 3.58/PY and 5.36/PY), with some but not all effects reaching statistical significance, likely due to limited statistical power. Hormonal contraceptive use/pregnancy, consistent condom use, and sampling around menses also affected VMB composition. Some product-related protective effects persisted after adjustment for these in mixed effects models. Conclusions: All three interventions were promising. Unlike antibiotics, vaginal probiotics will not affect other microbiota niches or cause antimicrobial resistance. Our results will be compared with those of other trials, and recommendations will be made for next steps, including the incorporation of molecular endpoints in trials.
Funding: This work was funded by the DFID/MRC/Wellcome Trust Joint Global Health Trials Scheme as a Development Project (grant reference MR/M017443/1; grant title: “Preparing for a clinical trial of interventions to maintain normal vaginal microbiota for preventing adverse reproductive health outcomes in Africa”). Vaginal probiotics for use in the trial were donated by the manufacturers (details will be presented).
Credits: None available.
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