Is Bacterial Vaginosis an STI? BV Testing and Partners

Key takeaways

CDC describes BV as an imbalance of vaginal bacteria. It’s not a classic STI with one germ passed between partners, but it’s linked to new or multiple partners, female partners and not using condoms.
BV is diagnosed by a clinician using an exam and simple lab checks, or with lab tests. CDC doesn’t recommend culture for diagnosing it.
BV can look like trichomoniasis or a yeast infection, and these need different tests, so a proper diagnosis matters.
CDC says women with BV are at higher risk of getting STIs, including HIV, and that all women with BV should be tested for HIV and other STIs.
Recurrence is common. A recent trial found treating male partners improved cure in women; current CDC guidelines don’t routinely recommend it, so ask your clinician.

Short answer: Not in the usual sense. CDC describes bacterial vaginosis (BV) as an imbalance of the bacteria in the vagina and says it’s unknown whether it comes from a single sexually transmitted germ. But BV is linked to sex, and CDC says it raises the risk of getting STIs, including HIV. That’s why CDC recommends that all women with BV be tested for HIV and other STIs (CDC).

This page is specific to BV. If you have symptoms and aren’t sure what’s going on, our broader guide is this an STD? covers more possibilities. Nothing here can tell you what you have. A clinician can, often in one visit.

So, is BV an STI?

A classic STI, like chlamydia or trichomoniasis, is caused by a specific germ that passes from one person to another during sex. Test for the germ and you have your answer.

BV doesn’t work that way. CDC’s treatment guidelines describe it as a vaginal dysbiosis: the usual balance of bacteria shifts away from the Lactobacillus bacteria that normally dominate. CDC says it’s unknown whether BV results from picking up a single sexually transmitted pathogen (CDC).

So the most accurate answer is “not exactly, but sex is involved.” That’s why BV appears in CDC’s STI treatment guidelines even though it doesn’t fit the classic definition.

How sex is linked to BV

CDC lists several things associated with BV (CDC):

Having multiple male partners
Having female partners
Having a new sex partner
Not using condoms
Douching

CDC also notes that male circumcision is associated with a lower risk of BV in female partners. Associated doesn’t mean caused by, and none of this means you did something wrong. BV is common, and it isn’t a judgment on anyone’s sex life.

Same-sex couples: BV is associated with having female partners. CDC notes that no studies have looked at whether treating female partners prevents BV from coming back. If you and a partner both have symptoms, it’s reasonable for each of you to be checked.

How BV is diagnosed

BV is usually diagnosed by a clinician, not by a standard STI panel. CDC describes a few ways to do it (CDC):

Method	What it involves
Amsel criteria	A clinical diagnosis that needs at least three of four findings: thin, uniform discharge; “clue cells” under the microscope; vaginal pH above 4.5; and a fishy odor, with or without adding a test solution (the “whiff test”)
Gram stain (Nugent score)	A lab looks at the bacteria on a slide and scores the balance. CDC calls this the reference standard.
Lab molecular tests	PCR-based tests on a vaginal swab. CDC notes some are FDA cleared and that they’re meant for people with symptoms.
Point-of-care tests	Rapid tests some clinics use during the visit

CDC says culture isn’t recommended for diagnosing BV because it isn’t specific (CDC). That’s worth knowing if you’re handed a result that only says a certain bacteria “grew.”

A pH strip on its own can’t confirm BV either. In the Amsel criteria, pH is just one of four findings, and at least three are needed. That’s one reason a clinician visit beats guessing from a home pH test.

BV vs trich, yeast and chlamydia or gonorrhea

Several conditions can cause discharge, odor, itching or irritation. They overlap enough that symptoms alone often can’t tell them apart, and each needs its own test.

Condition	How it fits	Testing
Bacterial vaginosis	Bacterial imbalance linked to sex, not a classic STI	Clinical criteria, Gram stain or a lab molecular test
Trichomoniasis	An STI that CDC lists among those BV raises the risk of	Its own specific test. See our trichomoniasis testing guide.
Yeast infection	A separate condition with some overlapping symptoms	Checked by a clinician during the same kind of visit
Chlamydia and gonorrhea	STIs that CDC lists among those BV raises the risk of	Lab tests on urine or swabs from the body sites involved. See our sample types guide.

The point isn’t to sort yourself into one row. It’s that a BV result doesn’t rule out an STI, and a negative STI panel doesn’t rule out BV. You can have more than one thing at once. If you tested negative for STIs and still have symptoms, see what to do next. If burning when you pee is part of it, our guide to UTI vs STI may help.

Why BV means you should think about STI testing

This is the part most people don’t expect. CDC says women with BV are at increased risk of getting STIs. It names HIV, gonorrhea, chlamydia, trichomoniasis, Mycoplasma genitalium, HPV and HSV-2 (CDC).

Because of that, CDC’s guidelines say all women with BV should be tested for HIV and other STIs (CDC). That doesn’t mean you have one. It means a BV diagnosis is a natural moment to check, especially if you have a new partner or it’s been a while since your last test.

Which tests make sense depends on your situation. CDC’s screening recommendations vary by age, pregnancy and other factors. Match tests to the body sites involved and to the timing of any recent exposure.

Possible HIV exposure in the last 72 hours?

Don’t wait for a BV or STI appointment. CDC says PEP must be started within 72 hours of a possible exposure, and sooner is better (CDC). Contact a clinician, urgent care or emergency room now. For ongoing HIV prevention, FreePrEP.org explains how to get PrEP.

Cost a barrier? Free and low-cost testing exists through health departments, HRSA health centers and programs like TakeMeHome. See free STD testing.

Recurrence and the partner-treatment question

BV coming back is common. CDC says persistent or recurrent BV is common and outlines options clinicians use for it (CDC). Treatment choices, including longer-term options, are a conversation for your clinician. This page won’t cover medicines or doses.

What about partners?

This is where the conversation has been changing. CDC’s current treatment guidelines say routine treatment of male partners isn’t recommended, noting that an earlier large trial found treating male partners didn’t reduce recurrence (CDC).

Then, in 2025, the New England Journal of Medicine published a randomized trial (often called StepUp) in which male partners of women with BV, in monogamous couples, were also treated with oral and topical antibiotics (Vodstrcil et al., NEJM). A later paper on NIH’s PubMed Central describes the trial as the first successful randomized trial of male partner treatment and reports that treating both partners significantly improved cure for women over a three-month period, compared with treating the woman alone (PubMed Central).

What that means for you:

It’s a promising finding, but CDC’s guidelines linked here haven’t made partner treatment routine.
The trial looked at monogamous couples with male partners. It doesn’t tell us about female partners or other situations.
If BV keeps coming back, it’s reasonable to ask your clinician, “Would treating my partner make sense for us?”

If you’re working through how to bring this up with a partner, our guide to telling a partner about an STI has wording that can be adapted for BV too.

A simple plan

Get a real diagnosis. See a clinician for symptoms like new discharge or odor, especially if this is your first time or something feels different.
Ask for STI testing at the same visit. CDC recommends HIV and STI testing for everyone diagnosed with BV.
If it keeps coming back, ask about recurrence options and whether partner treatment fits your situation.
Still have symptoms after treatment or a negative test? Go back. Something else may be going on, or more than one thing at once.

Turn this into a plan

Figure out what you actually need

Start with your situation: timing, symptoms, and which body sites were involved. Our home page walks you through it.

Build a testing plan →

Frequently asked questions

Is BV an STD?

Not in the usual sense. CDC describes BV as an imbalance of vaginal bacteria and says it’s unknown whether it comes from a single sexually transmitted germ. It is linked to sexual activity, including new or multiple partners.

Can you get BV without having sex?

BV is associated with sexual activity, but it’s also linked to things like douching. Because there isn’t one germ known to cause it, BV isn’t something a partner simply gives you the way they could give you chlamydia.

Should my partner be treated for BV?

CDC’s current treatment guidelines don’t recommend routine treatment of male partners. A 2025 randomized trial published in the New England Journal of Medicine found that treating male partners in monogamous couples improved cure for women. Ask your clinician whether partner treatment makes sense for you.

Does having BV mean I should get tested for other STIs?

Yes, according to CDC. Its guidelines say all women with BV should be tested for HIV and other STIs, because BV is linked to a higher risk of getting STIs.

Can an at-home test tell me if I have BV?

Some tests check vaginal pH or bacteria, but a high pH alone doesn’t confirm BV, and BV can look like other conditions. CDC describes diagnosis using several findings together or a lab test, so a clinician visit is the most reliable route.

Sources

Guidance changes. When timing or treatment matters, check the current linked guidance or ask a clinician.

Disclaimer: This article is for informational purposes only and does not diagnose, prescribe, or replace individualized medical care. Testing and treatment decisions should be made with a qualified healthcare provider.