New Study Confirms Bacterial Vaginosis (BV) is an STI—And Men Are the Missing Link

Groundbreaking Research Reveals a Shift in BV Treatment and Prevention

A major study led by researchers at Monash University and Alfred Health has confirmed that bacterial vaginosis (BV) is a sexually transmitted infection (STI)—a discovery that could revolutionise treatment and significantly reduce recurrence rates among women.

BV is the most common vaginal condition worldwide, affecting nearly one in three women and increasing the risk of infertility, premature birth, and newborn complications. Despite its prevalence, treatment has remained largely ineffective, with over 50% of women experiencing a recurrence within three months of receiving antibiotics.

However, this new study—published in the New England Journal of Medicine—has uncovered a key missing factor in the treatment of BV: male partners must also be treated to prevent reinfection.

Key Findings: Treating Both Partners Halves Recurrence Rates

Led by Professor Catriona Bradshaw and Dr Lenka Vodstrcil, the study followed 164 monogamous couples, where one partner had BV.

Participants were randomly assigned to two groups:

1. Women-only treatment (standard practice)

2. Couple treatment, where both partners received antibiotics—men took an oral antibiotic and applied a topical antibiotic cream.

The results were so striking that the trial was stopped early:

• BV recurrence was halved in the partner treatment group compared to women-only treatment.

• This proves that reinfection from untreated male partners plays a major role in persistent and recurrent BV.

  
  

Professor Bradshaw emphasised that this low-cost, short-term intervention has the potential to transform BV treatment worldwide:

"For the first time, we have a way to improve BV cure rates for women while also opening up exciting new opportunities for prevention."

Why BV Has Been Misunderstood for So Long

BV has long been considered a vaginal microbiome imbalance rather than an STI.

However, the study’s findings confirm that it meets several key STI criteria:

• It has a similar incubation period after sex as other STIs.

• It is strongly linked to changes in sexual partners and condom use—both classic STI risk factors.

• Studies have found BV-associated bacteria in male genitalia, yet previous research failed to treat men effectively.

This misunderstanding has led to a major gap in treatment, with standard guidelines only treating women—leaving them at high risk of reinfection.

"Previous trials that included male partners didn't improve cure rates because they failed to target bacteria on the penile skin properly," said Professor Bradshaw."Our study proves that treating both partners works—and that BV is, in fact, an STI."

A New Era for BV Treatment and Public Health

The findings have already led to changes in clinical practice at the Melbourne Sexual Health Centre, where couple-based treatment is now recommended.

To support this transition, researchers have launched an online resource for healthcare professionals and patients, offering guidelines on prescribing and accessing partner treatment.

Professor Bradshaw stressed that while updating international guidelines will take time, immediate action is needed:

"We felt an obligation to provide accurate, accessible information at the time of publication, so that women can start benefiting from these findings right away."

What’s Next? The Future of BV Research

While this study confirms BV’s status as an STI, scientists are still working to identify the exact bacterial cause. Advances in genomic sequencing are expected to pinpoint the responsible bacteria, allowing for even more targeted treatments in the future.

This discovery is a game-changer for women’s health, offering hope for millions who have struggled with recurrent BV. The shift towards treating both partners could drastically reduce cases, improving reproductive health outcomes worldwide.

As Professor Bradshaw concluded:

"BV has been misunderstood for far too long. It's time for a new approach—one that actually works."