Why BV Comes Back Even After Partner Treatment — New Study Finds Two Separate Causes

Researchers at Monash University and Bayside Health's Melbourne Sexual Health Centre have identified two distinct reasons bacterial vaginosis (BV) keeps coming back — even in women whose male partners were treated alongside them — a finding that could lead to more individually tailored BV treatment.

In this article:

• Building on last year's landmark discovery
• Two separate pathways to recurrence
• What's being trialed now
• Why this matters for recurrent BV patients

Building on Last Year's Landmark Discovery

In 2025, the same research team published a study in the New England Journal of Medicine showing that treating male partners alongside female patients reduced BV recurrence by more than 60%, confirming that BV behaves as a sexually transmissible condition. The discovery reshaped international thinking on BV and won the Australian Infectious Diseases Research Centre Eureka Prize for Infectious Diseases Research.

Two Separate Pathways to Recurrence

The team's newest study, published in The Lancet Obstetrics, Gynaecology & Women's Health, dug into a follow-up question: why does BV still come back for some women even when their partner was treated at the same time? The researchers identified two distinct mechanisms behind repeat diagnoses — re-infection from a partner, and persistence, where BV-causing bacteria survive the initial treatment course and resurface once couples resume sexual activity.

Lead author Dr. Lenka Vodstrcil explained that while partner treatment improves cure rates for most women in monogamous relationships, some women have persistent bacteria that outlast initial therapy. Distinguishing between the two pathways early, she said, opens the door to more intensive, female-focused treatment before a persistent infection takes hold again.

What's Being Trialed Now

Senior author Professor Catriona Bradshaw said her team is now trialing new treatment approaches, including longer antibiotic courses and new antibiotic combinations specifically designed to eradicate persistent BV-causing bacteria. The goal is to pair partner treatment — to address re-infection — with more intensive, individualized therapy for women whose bacteria simply weren't fully cleared the first time.

Why This Matters

For women who've done everything "right" — completed treatment, had their partner treated too — and still ended up with another BV diagnosis, this research offers a concrete explanation: not every recurrence has the same cause, and a one-size-fits-all treatment approach may be part of why cure rates have stayed stubbornly low. As these more targeted antibiotic strategies move through trials, they point toward future care that distinguishes between "got it again" and "never fully got rid of it" — two very different clinical problems requiring different fixes.

Conclusion

This is active research, not yet a new standard of care — the antibiotic combinations described are still being trialed. But it's a meaningful next step from a research group with a strong track record on BV, and it reinforces that recurrent BV is a more complex problem than current single-protocol treatment accounts for.

Sources

• News-Medical.net / Monash University, "New antibiotic combinations aim to prevent recurrent bacterial vaginosis" (September 30, 2026): news-medical.net