Bacterial vaginosis (BV) is one of the most common vaginal conditions affecting women of reproductive age. While antibiotics usually relieve symptoms, many women experience the frustration of BV returning weeks or months later.

For years, healthcare providers treated only the woman with BV because research had not shown a clear benefit from treating male partners. However, that has now changed.

A landmark clinical trial published in 2025 demonstrated that treating male partners at the same time as women can significantly reduce the risk of recurrent bacterial vaginosis. These findings have already influenced Australian clinical guidelines and represent one of the biggest advances in BV management in decades.

What Is Bacterial Vaginosis?

Bacterial vaginosis occurs when the normal balance of bacteria in the vagina changes. Healthy Lactobacillus bacteria become less dominant, allowing other bacteria to overgrow.

Common symptoms include:

• Thin grey or white vaginal discharge
• A strong "fishy" odour, particularly after sex
• Mild vaginal irritation
• Burning during urination (occasionally)

Some women have no symptoms at all.

Unlike yeast infections, BV is not caused by a fungus, and it is different from sexually transmitted infections (STIs) such as chlamydia or gonorrhoea. However, increasing evidence suggests that sexual activity plays an important role in the development and recurrence of BV.

Why Does BV Keep Coming Back?

Unfortunately, BV has one of the highest recurrence rates among common vaginal infections.

Studies have shown that more than half of women successfully treated for BV experience another episode within 3–12 months.

Possible reasons include:

• Persistence of BV-associated bacteria
• Biofilm formation inside the vagina
• Hormonal and vaginal microbiome factors
• Reinfection from an untreated sexual partner

For many years, clinicians suspected reinfection from male partners but lacked convincing evidence that treating men actually reduced recurrence.

That evidence is now available.

The Landmark Study That Changed Everything

In 2025, a landmark randomised controlled trial published in The New England Journal of Medicine investigated whether treating male partners alongside women with bacterial vaginosis could reduce the risk of recurrence.

The study included heterosexual couples in which the woman had bacterial vaginosis. All women received standard recommended treatment. Half of the male partners also received treatment consisting of:

• Oral metronidazole tablets for 7 days
• Topical clindamycin cream applied to the penile skin for 7 days

The findings were compelling.

Women whose male partners received treatment experienced significantly fewer BV recurrences over the following 12 weeks compared with women whose partners were not treated. The benefit was so clear that the clinical trial was stopped early, as continuing without offering treatment to all eligible participants was no longer considered appropriate.

The results provide strong evidence that treating both partners can help reduce recurrent bacterial vaginosis in many heterosexual couples and have prompted updates to Australian clinical recommendations.

Does This Mean BV Is Sexually Transmitted?

The answer is more nuanced than a simple yes or no.

BV is not officially classified as a traditional sexually transmitted infection (STI) like chlamydia or gonorrhoea.

However, researchers now recognise that BV-associated bacteria can be exchanged between sexual partners, contributing to recurrence in women. The latest evidence strongly supports sexual transmission as an important factor in recurrent BV, particularly in ongoing heterosexual relationships.

This doesn't mean every case of BV is sexually transmitted, but it does help explain why some women experience repeated infections despite completing appropriate treatment.

Australian Guidelines Have Changed

Following publication of the landmark clinical trial, Australian treatment recommendations have been updated.

Current guidance now recommends considering concurrent treatment of male partners for women with bacterial vaginosis who are in an ongoing heterosexual relationship.

The recommended male partner treatment includes:

• Metronidazole 400 mg taken orally twice daily for 7 days
• Clindamycin 2% cream applied to the penile skin twice daily for 7 days

Couples are generally advised to:

• Start treatment at approximately the same time
• Avoid sexual contact until both partners have completed treatment
• Use condoms if sexual activity occurs during treatment

It is important to note that topical clindamycin cream may weaken latex condoms for up to 72 hours after the final application.

Should Every Male Partner Be Treated?

Not necessarily.

Partner treatment may be appropriate when:

• The woman has symptomatic bacterial vaginosis
• She is in an ongoing heterosexual relationship
• The aim is to reduce recurrent BV

Treatment should always be individualised. A doctor will consider factors such as previous BV episodes, pregnancy, allergies, other medical conditions, and potential medication interactions before recommending partner treatment.

What About Same-Sex Partners?

Research into partner treatment among female same-sex couples is ongoing.

Current evidence is strongest for heterosexual couples because the landmark clinical trial specifically studied women with male partners. Recommendations may evolve as further research becomes available.

Can BV Affect Fertility or Pregnancy?

Untreated bacterial vaginosis has been associated with several important health risks, including:

• Increased susceptibility to sexually transmitted infections
• Pelvic inflammatory disease
• Pregnancy complications such as preterm birth
• Increased risk of infection following certain gynaecological procedures

Persistent or recurrent symptoms should be assessed by a healthcare professional rather than repeatedly self-treating.

Can I Get Treatment Online?

If you think you may have bacterial vaginosis, an AHPRA-registered Australian doctor can assess your symptoms through a telehealth consultation.

Where clinically appropriate, they may:

• Assess your symptoms
• Recommend pathology testing if required
• Prescribe appropriate treatment
• Discuss whether concurrent treatment for your male partner may be appropriate based on the latest evidence and Australian recommendations

Frequently Asked Questions

Does treating my boyfriend stop BV from coming back?

The latest high-quality clinical evidence shows that treating male partners alongside women significantly reduces the risk of recurrent bacterial vaginosis in ongoing heterosexual relationships.

Does my male partner need antibiotics?

Not always. Whether your partner should receive treatment depends on your individual circumstances and should be determined by a doctor.

Can men have bacterial vaginosis?

No. Men do not develop bacterial vaginosis because they do not have a vaginal microbiome. However, they can carry BV-associated bacteria on the penile skin or within the urethra, which may contribute to recurrence in female partners.

Should we avoid sex during treatment?

Yes. Australian guidelines recommend avoiding sexual contact until both partners have completed treatment. If sexual activity occurs during treatment, condoms are recommended, although topical clindamycin can weaken latex condoms for up to 72 hours after the final application.

What if BV keeps returning?

If BV continues to recur despite treatment, speak with a healthcare professional. Additional investigations or alternative treatment strategies may be needed.

The Bottom Line

For decades, bacterial vaginosis was treated as a condition affecting only women. Thanks to a landmark clinical trial and the high-quality evidence it provided, we now know that treating male partners can significantly reduce recurrence in many heterosexual couples.

This important research has already influenced Australian treatment recommendations and offers new hope for women who have experienced repeated episodes of BV.

If you're experiencing recurrent bacterial vaginosis, speaking with a doctor about whether simultaneous partner treatment is appropriate may help reduce the risk of the infection returning.

Disclaimer

This medical blog provides general information and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult with your regular doctor for specific medical concerns. The content is based on the knowledge available at the time of publication and may change. While we strive for accuracy, we make no warranties regarding completeness or reliability. Use the information at your own risk. Links to other websites are provided for convenience and do not imply endorsement. The views expressed are those of the authors and not necessarily representative of any institutions.