Can you get an STI from oral sex?

Public-health bodies list oral sex alongside vaginal and anal sex as a route for STIs. Herpes, gonorrhoea, syphilis and HPV are among the infections that can be passed between the mouth and the genitals or anus, and chlamydia can also affect the throat.

A cold sore on the lips is caused by a herpes virus, and it can be passed to a partner's genitals during oral sex, causing genital herpes. This is one reason to avoid oral sex while a cold sore or any sore is present.

Infections in the throat often cause no symptoms, or only a mild sore throat, so they can go unnoticed. Routine tests do not always include a throat swab, so it helps to tell the clinic about the kinds of sex you have. This is a normal question for them and helps them choose the right tests.

Condoms on a penis and dental dams over the vulva or anus act as a barrier and reduce the risk of most infections, though herpes and HPV can still pass from skin that is not covered. Vaccines protect against HPV and hepatitis B.

Avoiding oral sex when either partner has sores, blisters or a cold sore, and regular testing, add further protection. If you have symptoms or a partner tells you they have an STI, a sexual health clinic can advise on testing and treatment.