Lactobacilli-containing vaginal probiotics to cure or prevent bacterial or fungal vaginal dysbiosis: a systematic review and recommendations for future trial designs

Abstract

BACKGROUND: Vaginal probiotics claiming to cure and/or prevent bacterial and/or fungal vaginal dysbiosis are available on the market but, until recently, did not have to be approved as drugs for human use. OBJECTIVES: We evaluated the impact of vaginal probiotics on bacterial vaginosis (BV) and vulvovaginal candidiasis (VVC) cure and/or recurrence, as well as vaginal microbiota (VMB) composition and vaginal detection of probiotic strains. SEARCH STRATEGY: We performed a systematic literature search in MEDLINE and Embase up to 15 January 2019. SELECTION CRITERIA: There were no restrictions in probiotic strains/formulations, study populations, and designs. BV had to be diagnosed by Nugent or Ison-Hay Gram stain scoring, VVC by culture, wet mount or PCR, and VMB composition/detection by molecular techniques. DATA COLLECTION AND ANALYSIS: The authors independently extracted data. MAIN RESULTS: All 22 vaginal probiotics evaluated in the 34 eligible studies contained Lactobacillus strains, and some contained additional active ingredients. The probiotics hold promise for BV cure and prevention, but much less so for VVC cure and prevention. No major safety concerns were reported in any of the studies. Vaginal detection of probiotic strains never lasted long beyond the dosing period, suggesting that they did not colonise the vagina. However, findings are not definitive because heterogeneity was high and the quality of most studies suboptimal. CONCLUSIONS: Availability of vaginal probiotics for vaginal health indications will likely decline in 2020 because of regulatory changes. We urge the field to invest in clinical evidence-based product development and to conduct future trials more rigorously. TWEETABLE ABSTRACT: Lactobacilli-containing vaginal probiotics hold promise for bacterial vaginosis cure and prevention, but not for vulvovaginal candidiasis.