Recurrent bacterial vaginosis is a common condition in women of reproductive age and is characterized by a disruption of the normal vaginal microbiota, with a reduction in Lactobacillus species and an overgrowth of anaerobic bacteria such as Gardnerella vaginalis. Recurrence rates after standard antibiotic treatment are high. Lactobacillus crispatus is considered one of the most protective species for maintaining vaginal microbiota balance.

This multicenter, randomized, double-blind, placebo-controlled clinical trial aims to evaluate the efficacy and safety of a probiotic supplement containing Lactobacillus crispatus CRP21 (Crispavag® capsules) in reducing the incidence of recurrent bacterial vaginosis in women diagnosed with recurrent bacterial vaginosis. After standard antibiotic treatment, participants will be randomly assigned in a 1:1 ratio to receive either the probiotic supplement or a placebo for 12 weeks.

The primary objective is to evaluate whether supplementation with Lactobacillus crispatus CRP21 reduces the incidence of recurrent bacterial vaginosis episodes compared with placebo. Participants will be followed for a total of 24 weeks, including a 12-week treatment period and a 12-week follow-up period.

This study is a prospective, multicenter, randomized, double-blind, placebo-controlled clinical trial designed to evaluate the efficacy and safety of the probiotic Lactobacillus crispatus CRP21 in reducing the incidence of recurrent bacterial vaginosis in women diagnosed with recurrent bacterial vaginosis.

Bacterial vaginosis is characterized by a disruption of the normal vaginal microbiota, with a decrease in Lactobacillus species and an overgrowth of anaerobic bacteria such as Gardnerella vaginalis. Standard antibiotic therapies, such as metronidazole, are effective in treating acute episodes but recurrence rates remain high. Lactobacillus crispatus is strongly associated with vaginal health due to its ability to produce lactic acid and antimicrobial substances that inhibit pathogenic microorganisms.

In this study, women aged 18-45 years diagnosed with recurrent bacterial vaginosis will be enrolled. Following antibiotic treatment for the acute episode, participants will be randomly assigned in a 1:1 ratio to receive either a probiotic supplement containing Lactobacillus crispatus CRP21 (Crispavag® capsules) or a placebo. The investigational product will be administered orally at a dose of one capsule per day for 12 weeks.

The total duration of participation for each subject will be 24 weeks, including a 12-week treatment period and a 12-week post-treatment follow-up period. The primary outcome is the reduction in the incidence of recurrent bacterial vaginosis episodes during the study period. Secondary outcomes include time to first recurrence, changes in vaginal pH, evaluation of symptoms such as burning and itching, incidence of other genitourinary infections, treatment adherence, tolerability, and assessment of adverse events.

The study will be conducted at multiple clinical centers in Italy and aims to enroll approximately 156 participants. Results from this trial will provide evidence on the clinical effectiveness of Lactobacillus crispatus CRP21 supplementation in preventing recurrence of bacterial vaginosis.

Inclusion Criteria:

• Female participants aged 18 to 45 years
• Diagnosis of recurrent bacterial vaginosis
• At least three documented episodes of bacterial vaginosis in the previous 12 months
• Completion of standard antibiotic therapy for bacterial vaginosis before enrollment
• Willingness to comply with study procedures and follow-up visits
• Provision of written informed consent

Exclusion Criteria:

• Pregnancy or breastfeeding
• Current use of systemic antibiotics or antifungal therapy not related to treatment of bacterial vaginosis
• Known hypersensitivity to probiotic products or study components
• Presence of other significant gynecological infections requiring treatment
• Use of vaginal probiotic products within 30 days prior to enrollment
• Participation in another clinical trial within the previous 30 days

This study is double-blind with masking of participants, care providers, investigators, and outcomes assessors. The probiotic and placebo capsules are identical in appearance, packaging, and labeling to maintain blinding throughout the study.