Key Takeaways:
Partner Treatment Reduces Recurrence – Women whose male partners were treated had a 35% recurrence rate vs. 63% when only the woman was treated.
BV May Be Sexually Transmitted – Findings suggest BV is not just an imbalance but may involve sexual exchange of bacteria, challenging traditional views.
Potential Shift in Treatment – Some clinics, like Melbourne Sexual Health Centre, are already treating male partners, signaling a possible change in BV care.
Bacterial Vaginosis Bacteria. Credit: Dr Graham Beards
Researchers have discovered that bacterial vaginosis (BV) is a sexually transmitted infection (STI) and that treatment outcomes improve when male partners also undergo treatment.
Bacterial vaginosis is the most common cause of vaginal discharge among women of reproductive age, according to the World Health Organization (WHO). Until now, it was considered a simple condition. However, a new study published in the New England Journal of Medicine provides strong evidence that BV is, in fact, a sexually transmitted infection.
Treating Both Men and Women Improves Recovery
In their research, scientists from the Melbourne Sexual Health Centre at Monash University conducted a randomized, controlled trial involving 164 heterosexual couples in monogamous relationships where the woman had bacterial vaginosis. The study was designed to test whether treating male partners alongside female patients would improve cure rates and reduce recurrence.
81 couples were assigned to the partner-treatment group, where both the woman and her male partner received treatment.
83 couples were in the control group, where only the woman received standard care.
In the partner-treatment group, women received the standard first-line antimicrobial treatment, while men received a combination therapy consisting of:
Metronidazole (400 mg tablets, twice daily for 7 days)
2% Clindamycin cream (applied to the penile skin, twice daily for 7 days)
Major Reduction in Recurrence Rates
The results were so conclusive that the data and safety monitoring board decided to stop the trial early, as treating only women was shown to be significantly less effective.
Women who received treatment alone had a 63% recurrence rate (43 out of 68 women).
Women whose partners were also treated had a significantly lower recurrence rate of 35% (24 out of 69 women).
This represents a drastic reduction in recurrence risk, reinforcing the idea that BV is sexually transmitted and that treating both partners is key to improving outcomes.
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A New Treatment Approach for This STI
“We have long suspected that it is a sexually transmitted infection because it has an incubation period (after sexual contact) similar to most STIs and is associated with the same risk factors, such as chlamydia, including changing sexual partners and not using condoms,” said Dr. Lenka Vodstrcil, an epidemiologist and lead author of the study, in a press release.
While male partners typically do not show any symptoms, the study highlights that they may still be harboring BV-associated bacteria, unknowingly contributing to reinfection. Some men in the study experienced mild side effects from the treatment, including nausea, headaches, and a metallic taste, but these were generally well tolerated.
This discovery could change the way BV is managed in clinical practice. “There are no symptoms in men, so they have a harder time understanding that they are part of the problem,” Vodstrcil told National Geographic. “But we really emphasize that they can now be part of the solution.”
Final Thoughts: A Shift in BV Treatment
This study challenges the idea that BV is just an imbalance, but questions remain. If partner treatment helps, why does recurrence still happen in a third of cases? And will men take treatment for something they don’t feel?
Still, some clinics are already acting on the findings. The Melbourne Sexual Health Centre now treats male partners for recurrent BV, a shift that could set a new standard. It’s not a perfect solution, but for women struggling with recurrence, it may be worth discussing with a doctor.
FAQs: Bacterial Vaginosis and Partner Treatment
Is bacterial vaginosis (BV) really an STI?
BV is not classified as a typical STI, but research suggests it may be sexually exchanged. The study found that treating male partners significantly reduced recurrence, indicating a potential sexual transmission pathway.
How does treating male partners help prevent BV recurrence?
Men may harbor BV-associated bacteria without symptoms, leading to reinfection. The study showed that partner treatment nearly halved recurrence rates compared to treating only women.
What is the recommended treatment for male partners?
The study used a 7-day combination therapy:
Oral metronidazole (400 mg, twice daily)
2% clindamycin cream applied to the penile skin (twice daily)
Are there any side effects for men taking BV treatment?
Some men in the study experienced mild side effects, including nausea, headache, and a metallic taste**,** but these were generally well tolerated.
Will doctors start prescribing partner treatment for BV?
Some clinics, like the Melbourne Sexual Health Centre, are already implementing this approach for recurrent BV cases. Widespread adoption may depend on further research and guideline updates.
Should I ask my doctor about treating my partner if I have BV?
If you experience recurring BV, discussing partner treatment with your doctor may help reduce reinfection and improve long-term outcomes.
References
Vodstrcil, L. A., Plummer, E. L., Fairley, C. K., Hocking, J. S., Law, M. G., Petoumenos, K., Bateson, D., & StepUp Team. (2025). Male-partner treatment to prevent recurrence of bacterial vaginosis. The New England Journal of Medicine, 392(10), 947-957. https://doi.org/10.1056/NEJMoa2405404
World Health Organization. (n.d.). Bacterial vaginosis. Retrieved March 16, 2025, from https://www.who.int/news-room/fact-sheets/detail/bacterial-vaginosis