Can you have an STI without knowing?

Infections such as chlamydia, gonorrhoea, HPV, herpes and HIV can all be present without obvious symptoms. With chlamydia, for example, most people who have it notice nothing at all. When symptoms do appear, they may be mild, come and go, or be mistaken for something else, like thrush or a urinary tract infection.

Having no symptoms does not mean an infection is harmless or cannot be passed on. A partner may also have no idea they carry an infection, so a lack of symptoms on either side tells you little.

Untreated infections can cause problems later. Chlamydia and gonorrhoea can lead to pelvic inflammatory disease and fertility problems, syphilis can affect many organs and can pass to a baby in pregnancy, and some types of HPV can cause cancers over time.

The reassuring side is that the bacterial and parasitic STIs are usually cured with treatment, and viral ones such as HIV and herpes can be managed well. Finding them early makes all of this easier.

Regular testing, including when you have no symptoms, is the reliable way to know your status. Sexual health clinics test confidentially, and many places offer home self-sampling kits.

If a test comes back positive, clinics can help you let recent partners know, sometimes without naming you, so they can be tested and treated too. Condoms, dental dams and vaccines for HPV and hepatitis B lower the risk in the first place.