Can BV mean STD?

Officially, no. The NHS, CDC and most major health bodies don't classify bacterial vaginosis as a sexually transmitted infection. But this is genuinely one of the more unsettled questions in women's health right now, and research published in the last couple of years has made the picture more complicated, not less. Here's where things actually stand.

Is BV classed as an STI?

The standard position, from the NHS and CDC, is clear: BV is not classed as an STI. It's caused by an imbalance of bacteria that are already living in the vagina, rather than an organism passed from one person to another the way chlamydia or gonorrhoea are. That's the official line, and it's still what you'll be told at a GP or sexual health clinic.

That said, it isn't the whole story. A 2025 study published in the journal Sexually Transmitted Infections, covered by the BBC and CNN, argued that BV meets the epidemiological profile of a sexually transmitted infection and should be reclassified as one. Some specialists already treat it that way in practice: UpToDate notes that "many specialists" consider BV a de facto STI even without the formal classification, and Australian STI guidelines describe it as having "the epidemiological profile of a sexually transmissible infection." So the honest answer is that the science is actively shifting, even if the classification hasn't caught up yet.

So can a partner give you BV?

In practice, yes, bacteria can be exchanged during sex in a way that disrupts your vaginal balance, even though BV isn't "caught" in the same way as a classic STI. The NHS is direct about this: you can pass BV to a woman, or to anyone with a vagina, during sex. This is also why BV can spread between female partners, and why couples using dental dams and condoms on shared sex toys can reduce that risk. If a partner has a vagina and has been diagnosed with BV alongside you, both of you may need treatment before resuming sexual activity.

Male partners are a different story, since men don't develop BV themselves. Historically this meant male partners weren't treated at all, but recent trial evidence has started to change that advice for couples dealing with recurrent BV. We've gone into that specific research, along with the fuller picture on risk factors and recurrence, in Who Is Most Likely To Get BV?

Is BV a sign my partner has been unfaithful?

Not necessarily, and it's worth being careful with this assumption. BV can develop for reasons that have nothing to do with a new sexual contact, including douching, perfumed products, tight clothing, smoking, stress or simply a naturally lower level of protective bacteria. It's true that BV can follow exposure to a new partner's bacteria, but a diagnosis on its own isn't evidence of anything beyond what it says on the test: a bacterial imbalance. We've covered the full list of everyday triggers in What Is The Main Cause Of BV?

What gets mistaken for BV?

Because BV's symptoms overlap with several other conditions, misdiagnosis (in both directions) is common enough that it's always worth getting a proper swab test rather than self-diagnosing.

• Thrush (yeast infection): the opposite pH problem to BV, but both cause discharge and irritation, and it's easy to confuse the two. Thrush discharge is typically thicker and white, without the fishy odour, and treating BV with anti-thrush medication (or vice versa) won't work.
• Trichomoniasis: an actual STI caused by a parasite, trichomoniasis can cause a similar thin, unusual discharge and odour to BV, which makes clinical testing essential to tell them apart.
• Chlamydia: chlamydia is often symptomless, like BV, and the two can occur together often enough that a chlamydia test is usually recommended alongside a BV diagnosis. We've covered the specific link between the two, including why a BV-disrupted vaginal environment can occasionally affect chlamydia test accuracy, in Can BV Cause A Positive Chlamydia Test?

Why the classification actually matters

This isn't just an academic debate. Whether BV is treated as an STI affects whether partners get tested and treated, whether protection is recommended during treatment, and how seriously recurrent cases get investigated. Until the guidelines formally catch up with the newer research, the practical approach is the same either way: get a proper diagnosis rather than guessing, and if BV keeps coming back, raise the partner-transmission question directly with a GP or sexual health clinic rather than assuming there's nothing more to look into.

If you're dealing with BV that won't stay away, we've covered what that can mean long-term in What does untreated BV lead to?