Treating vaginitis with probiotics in non-pregnant females: A systematic review and meta-analysis

Vaginitis, also known as vulvovaginitis, is an inflammation of the vagina and vulva and a common disease in females. It is thought to be caused by vaginal dysbiosis and improved by probiotics. Bacterial vaginosis (BV) and vulvovaginal candidiasis (VVC) are the major types of vaginal infections. The present systematic review and meta-analysis aimed to clarify the efficacy of probiotics in the treatment of common vaginal infections in non-pregnant females. Literature on randomized controlled trials and two-armed prospective studies on any intervention with probiotics published until December 24th, 2018 was searched in the PubMed, Cochrane and EMBASE databases. The outcomes of interest were recurrence rate, cure rate, remission rate and normal vaginal flora restoration. Finally, a total of 30 studies on bacterial vaginosis (BV) and/or VVC were included and stratified into 3 study types based on treatment design as follows: Type I, antibiotic/probiotics vs. antibiotics/antifungals (22 studies); Type II, probiotics vs. placebo (5 studies); Type III, probiotics vs. antibiotics (3 studies). The type I studies comprised 1,788 non-pregnant females and had the highest inter-study comparability in post-treatment follow-up design and meta-analysis outcome data. Probiotics interventions were significantly associated with a lower recurrence rate of vaginitis [pooled odds ratio (OR)=0.27, 95% CI: 0.18-0.41, P<0.001] and higher cure/remission rate (pooled OR=2.28, 95% CI: 1.20-4.32, P=0.011). However, a significant increase in normal vaginal flora after probiotic treatment was observed only in BV (pooled OR=4.55, 95% CI: 1.44-14.35, P=0.01). In addition, supportive but heterogeneous results were obtained from the 6-month follow-up data of Type-I studies, different infection types and supplementary analysis of Type-II studies. In conclusion, probiotics have a significant short-term effect in the treatment of common vaginal infections in non-pregnant females. In order to evaluate the long-term effects of probiotics in common vaginal infections, it is worthwhile to perform higher-quality clinical trials in the future.