Bacterial vaginosis and HIV

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Key points

  • Bacterial vaginosis occurs when the balance of normal bacteria in the vagina becomes disrupted.
  • Bacterial vaginosis is common and various activities seem to increase the risk.
  • Having bacterial vaginosis increases the risk of getting a sexually transmitted infection, including HIV, or passing one on to sexual partners.

Bacterial vaginosis (BV) is a condition which occurs when the normal balance of bacteria in the vagina becomes disrupted. This can result in an over-growth of certain bacteria, which can be accompanied by unpleasant symptoms.

It is a very common condition and can affect any woman or person with a vagina. It is not a sexually transmitted infection (STI) and is easily treated with antibiotics.

Having bacterial vaginosis increases your risk of acquiring HIV and STIs including herpes, human papillomavirus (HPV), chlamydia and gonorrhoea. For people living with HIV, having bacterial vaginosis increases the risk of passing on HIV during sex and childbirth. However, this is not the case if you are receiving HIV treatment and have an undetectable viral load.

Causes of bacterial vaginosis

What causes the imbalance of bacteria in the vagina which leads to bacterial vaginosis is not fully understood. Since you can develop bacterial vaginosis without having ever had sex it is not classified as an STI, but sexual activity appears to increase the likelihood of developing it. For reasons that remain unclear, there are higher rates of bacterial vaginosis among lesbian, bisexual and other women who have sex with women than among heterosexual women.

These activities can increase the risk of developing bacterial vaginosis:

  • having a new sexual partner or several sexual partners
  • washing the vagina (douching) and using soap or vaginal deodorant
  • using strong detergents to wash your underwear
  • smoking
  • being given oral sex (licking of the vagina)
  • using bubble bath, shower gel, scented soaps or antiseptic washes
  • having an intrauterine device (IUD) fitted.

Bacterial vaginosis is common during pregnancy.

These activities can reduce the risk of developing bacterial vaginosis:

  • Using condoms and dental dams during sex
  • Cleaning, or changing condoms on, sex toys before sharing them with sexual partners
  • Using an oral contraceptive pill
  • Having showers rather than baths.

Studies have also shown a reduced risk of bacterial vaginosis in women whose male sexual partners are circumcised.


Bacterial vaginosis is often asymptomatic, meaning you experience no symptoms at all. When they do occur, symptoms can include changes to vaginal discharge, including turning grey or whitish, watery or developing a fishy smell. This may be worse after sex.

Bacterial vaginosis is not usually associated with itchiness, irritation, sores, blisters, or vaginal bleeding. If you have any of these symptoms, seek advice from your GP or sexual health clinic.


If you think you have bacterial vaginosis, you can go to your GP or a sexual health clinic. A doctor or nurse will examine you to look for signs of bacterial vaginosis. They may be able to diagnose bacterial vaginosis straight away because of the distinctive appearance of the discharge.

If not, they will probably use a swab to collect a sample from your vagina. A swab looks like a cotton bud and collecting a sample only takes a minute or two. It shouldn’t be painful, but it may feel a little uncomfortable. The sample will then be sent to a lab for testing and you should get your results within a few days.

They may also test you for sexually transmitted infections if the symptoms are similar.

Sexual health screens are freely available from NHS genitourinary medicine (GUM) and sexual health clinics. Many HIV clinics also provide sexual health screens and tests for bacterial vaginosis as part of their routine care.


Bacterial vaginosis sometimes goes away by itself as the balance of bacteria in the vagina corrects itself. If bacterial vaginosis is not bothering you, it is not always necessary to have it treated. However, it can increase the chance of acquiring HIV or passing it on if you have a detectable viral load. Treatment for bacterial vaginosis is recommended if you have a different HIV status from your partner and one of you has a detectable viral load.


bacterial vaginosis

A condition caused by the overgrowth of certain species of the bacteria that are normally present in the vagina.


Any perceptible, subjective change in the body or its functions that signals the presence of a disease or condition, as reported by the patient.


sexually transmitted infections (STIs)

Although HIV can be sexually transmitted, the term is most often used to refer to chlamydia, gonorrhoea, syphilis, herpes, scabies, trichomonas vaginalis, etc.


Single-celled micro-organisms.

detectable viral load

When viral load is detectable, this indicates that HIV is replicating in the body. If the person is taking HIV treatment but their viral load is detectable, the treatment is not working properly. There may still be a risk of HIV transmission to sexual partners.

It is also important to be treated if you are going to have a surgical procedure that involves going through the neck of your womb (the cervix). If bacterial vaginosis is transmitted from the cervix into the womb during a procedure, you can develop a serious condition called pelvic inflammatory disease.

If you are pregnant or thinking about becoming pregnant, you may also want to be treated. There is some evidence that bacterial vaginosis can increase the risk of premature birth, especially if you have had a miscarriage, premature baby or baby with a low birth weight before. There is also a greater risk of passing on HIV to a baby during delivery. You can safely take treatment during pregnancy.

If you have a same-sex partner, your doctor or nurse may also recommend that they are treated.  

Treatment is with antibiotics, usually either metronidazole or clindamycin. It can be given as tablets (a single larger dose or doses over seven days) or a vaginal gel over five to seven days. It is important that you take all the treatment prescribed to you. You will need to avoid alcohol during treatment and for 48 hours after you have finished it, as it will make you feel very sick.

There is a lot of information online about complementary therapies to prevent or treat bacterial vaginosis, such as probiotics. However, the evidence of their effectiveness is inconclusive and therefore their use is not recommended by clinicians.

It is common for bacterial vaginosis to recur after treatment, so you may require another course of treatment at a later date. If you have frequent bouts of bacterial vaginosis, your doctor may recommend preventive treatment with antibiotics.

Using condoms can help reduce the risk of bacterial vaginosis recurring. The vaginal gel can weaken latex, so you will need to use non-latex condoms while using this treatment.

Next review date

Thanks to Dr Phillip Hay for his advice.