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Sexually transmitted infections (STI)

Sexually transmitted infections (STIs) can be passed on when you have unprotected sex or close sexual contact with someone who already has an STI.

Using a male (external) or female (internal) condom or dental dam every time you have sex is the best way to prevent STIs. Getting tested regularly for STIs will also help you to look after your sexual health.

Most STIs can be easily treated, however without treatment they can sometimes lead to more serious health problems.

If you think you have an STI, it’s important to see a healthcare professional rather than trying to diagnose it yourself, as symptoms can vary from person to person. 

Find out more here about the different types of STIs, their symptoms, testing and treatment options and how to protect yourself from them.

Next full review: 
25 November 2018
chlamydia in a human cell
Chlamydia doesn't always have symptoms, and can lead to serious health problems if left untreated.
Herpes virus
Genital herpes causes sores that are really infectious. Get treated quickly.
Human papilloma virus (HPV)
Genital warts cause small bumps on the skin. They can be treated with creams or by freezing them.
Gonorrhoeae bacteria
Gonorrhoea doesn't always have symptoms, but it can be treated with a short course of antibiotics.
Hepatitis virus
Hepatitis B is very infectious and can seriously affect your liver. It has flu-like symptoms.
Hepatitis C virus
Hepatitis C is found in infected blood. It's mainly passed on through sharing injecting equipment, but can also be transmitted through unprotected sex where blood is present.
Syphilis bacteria
Syphilis can be treated with antibiotics, but without treatment it can lead to serious health issues.
Trichomoniasis parasite
Trichomoniasis is caused by a tiny parasite. It is easy to treat but most people don’t have any symptoms.
Hepatitis A viruses on colourful background
Hepatitis A is usually passed on through contaminated food and water, but it’s also a sexually transmitted infection. 
A single pubic louse on a hair
Pubic lice are passed on through close bodily contact with someone who has them and are usually sexually transmitted.
dgital image of HPV under microscope
There are over 100 different strains of HPV. Some strains of the virus are more risky than others.
Last updated:
15 May 2020
Next full review:
25 November 2018