Do sexual partners of individuals with bacterial vaginosis (BV) need to be treated?

Treatment of Sexual Partners in Bacterial Vaginosis

No, sexual partners of women with bacterial vaginosis do not need to be treated according to established CDC guidelines, though this recommendation is now challenged by the highest quality recent evidence showing significant benefit from concurrent partner treatment. 1, 2

Current Guideline Recommendations vs. Recent Evidence

Traditional Guideline Position

• CDC guidelines have consistently stated that treatment of male sex partners has not been beneficial in preventing BV recurrence in women 3, 1
• The principal goal of BV therapy is to relieve vaginal symptoms in the affected woman, not to prevent transmission 1
• Male partners are typically asymptomatic even when carrying BV-associated bacteria 4
• This recommendation has been the standard of care for decades 3

Groundbreaking 2025 Evidence

However, a landmark 2025 randomized controlled trial published in the New England Journal of Medicine directly contradicts these longstanding guidelines and demonstrates clear benefit from partner treatment. 2

• In this trial, concurrent male partner treatment reduced BV recurrence from 63% to 35% within 12 weeks (absolute risk reduction of 28%) 2
• The recurrence rate dropped from 4.2 per person-year (control group) to 1.6 per person-year (partner-treatment group), representing a statistically significant difference (P<0.001) 2
• The trial was stopped early by the data safety monitoring board because treating women only was clearly inferior to treating both partners 2

Why Previous Guidelines Were Wrong

Flaws in Historical Evidence

• All six previous randomized trials that formed the basis for CDC recommendations had significant methodological flaws 5
• These trials used suboptimal treatment regimens in women, failed to report adherence, had inadequate randomization methods, and were severely underpowered 5
• None assessed whether antibiotic treatment actually affected the penile microbiota 5
• A 2016 Cochrane review found low to very low quality evidence supporting the "no treatment" recommendation 6

Microbiological Evidence Supporting Partner Treatment

• BV-associated bacteria are found in the male genital tract (penile skin and urethra) and can be sexually exchanged between partners 7, 2
• A 2021 pilot study showed that concurrent partner treatment significantly reduced BV-associated bacteria at all three anatomical sites (vagina, penile skin, and male urethra) immediately post-treatment 7
• Women who have never been sexually active rarely develop BV, suggesting sexual transmission plays a role 3

Recommended Partner Treatment Regimen

Based on the 2025 NEJM trial, the effective partner treatment protocol is: 2

• For the woman: Standard first-line treatment (oral metronidazole 500 mg twice daily for 7 days OR intravaginal clindamycin/metronidazole) 8, 2
• For the male partner: Combined oral and topical therapy:
  • Metronidazole 400 mg orally twice daily for 7 days 2
  • Clindamycin 2% cream applied to penile skin twice daily for 7 days 2

Safety and Tolerability in Male Partners

• Men tolerated the combination therapy well in clinical trials 7, 2
• Common adverse events included nausea, headache, and metallic taste 2
• Men must avoid alcohol during metronidazole treatment and for 24 hours afterward due to potential disulfiram-like reaction 1, 8
• Adherence to treatment was good in the 2025 trial 2

Clinical Implementation

Given the dramatic reduction in recurrence rates demonstrated in the 2025 NEJM trial, concurrent male partner treatment should be strongly considered, particularly for: 2

• Women with recurrent BV (≥2 episodes in 6 months or ≥3 in 12 months) 9
• Women in monogamous heterosexual relationships 2
• Couples willing to adhere to the full 7-day treatment course 2

Important Caveats

• The 2025 evidence applies specifically to heterosexual couples in monogamous relationships 2
• Treatment of multiple or casual partners has not been studied 2
• Female-to-female transmission has not been addressed in these trials 2
• Current CDC guidelines have not yet been updated to reflect this 2025 evidence 1

The Bottom Line

While established CDC guidelines state partner treatment is not necessary, the single highest quality and most recent study (2025 NEJM) provides Level 1 evidence that concurrent male partner treatment reduces BV recurrence by nearly 50%. 2 This represents a paradigm shift in BV management that prioritizes improved patient outcomes (reduced recurrence and associated morbidity) over outdated recommendations based on flawed historical trials. 2, 5