Treating Partners Could Finally Cure Bacterial Vaginosis

Researchers in Australia are closing in on a lasting cure for bacterial vaginosis, the most common vaginal condition among women of reproductive age. The team at Monash University and Bayside Health's Melbourne Sexual Health Centre is now testing new antibiotic combinations and longer courses of treatment aimed at the women for whom the infection keeps returning. The effort builds on a discovery that reshaped international thinking on the condition: bacterial vaginosis is sexually transmissible, and treating a woman's partner is one of the most effective steps a doctor can take.

The most stubborn fact about bacterial vaginosis has always been how reliably it comes back. The condition begins when healthy vaginal bacteria decline and other bacteria overgrow, upsetting the balance of the vaginal microbiome. Antibiotics clear it, and then for more than half of women the infection returns within three months. According to the team's latest research, those repeat diagnoses travel along two distinct pathways: reinfection from a partner, or bacteria that survive the treatment itself and re-establish themselves.

Treating both partners changed the picture

In 2025 the same researchers published a landmark trial in the New England Journal of Medicine that treated bacterial vaginosis as a sexually transmitted infection. Rather than medicating only the woman, the trial gave her male partner oral metronidazole tablets plus clindamycin cream applied to the penile skin, twice daily for a week, while she received the standard recommended antibiotics. The results were strong enough that a safety monitoring board ended the trial early: recurrence fell by more than sixty percent. Bacterial vaginosis returned in 35 percent of women whose partners were treated, compared with 63 percent in the control group, after twelve weeks of follow-up.

The finding earned the team this year's Australian Infectious Diseases Research Centre Eureka Prize for infectious diseases research. For the first time, doctors had a clear explanation for why so many women kept relapsing and a cheap, short intervention that worked. But partner treatment did not end every case. Some women tested positive again even when their partners finished the full course, and until this year nobody could say exactly what separated them from the women who stayed clear.

Two reasons the infection returns

The new study, published in The Lancet Obstetrics, Gynaecology & Women's Health, pooled data from couples treated together and traced the repeat diagnoses back to their source. Some women were reinfected after treatment. Others carried bacterial vaginosis bacteria that survived the initial therapy and took hold again before the couple resumed sex. Lead author Dr. Lenka Vodstrcil, a senior research fellow at Monash University, said the distinction should change how doctors treat the condition: "While partner treatment improves cure for most women in a monogamous relationship, there are some women who have persistent BV bacteria that survive initial therapy before couples resume sex after treatment."

Which pathway a woman is on matters because each needs a different response. Reinfection is blocked by treating both partners at once, and that is already proven. Persistence needs a heavier hand against the bacteria themselves, which is where the new trial designs come in. Senior author Professor Catriona Bradshaw said her team is testing longer antibiotic courses and new combinations designed to eradicate the bacteria that survive standard treatment. "Using partner treatment to mitigate reinfection and more intensive strategies that target persistence of BV bacteria, we hope to create more effective treatment approaches that can be tailored to an individual and achieve higher levels of cure for all women," Bradshaw said.

The long-term goal is treatment fitted to the patient instead of one protocol for everyone: women whose infections persist would move straight to the more intensive, female-focused treatment before the infection can take hold again, while couples keep getting treated together to cut off reinfection. For the millions of women who have cycled through repeat courses of bacterial vaginosis treatment, the shift could mean the difference between managing a recurring condition and being finished with it. Details of the research were reported by Medical Xpress and News-Medical.