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All you need to know about sexual infections

What are sexually transmitted infections (STIs)?

An STI is an infection which is caused by bacteria, viruses or parasites and is passed on through sexual contact. You can catch one if you have unprotected vaginal, anal or oral sex, by genital contact and through sharing sex toys. You don’t need to have lots of sexual partners to get an infection. There are many types of STIs, but they are not always easy to spot because you may be asymptomatic (not showing any symptoms). You can also have more than one at a time! 

Find out about the most common STIs:


  • This STI spreads through sex (vaginal, anal or oral) with someone who has the infection. 
  • Many people who have chlamydia don’t know they do because they don’t have symptoms which means that they can continue to spread it through unprotected sex.
  • People who do have symptoms can experience the following:
  • Thick yellow discharge from the penis or vagina
  • Pain or burning when peeing
  • Pain or bleeding during sex
  • Fever

Chlamydia can be treated with antibiotics. Don’t have oral, vaginal or anal sex, or use sex toys, until you and your partner(s) have both finished the treatment and any symptoms have gone. This is to help prevent you being re-infected or passing the infection on to someone else. You and your partner still need to avoid sex for 7 days after starting the treatment as that’s how long it takes to work.


  • Herpes is an oral and/or genital infection caused by a virus.
  • Any skin-to-skin contact with infected areas can pass along herpes (if the virus is active on the skin outside of the area protected by a condom or dam), even if the person who has herpes doesn’t have any visible sores or other symptoms. 
  • Once you have herpes, the virus is always in your body, so it can pass through oral, vaginal, or anal sex. 
  • Some people do not experience any symptoms at all. But many people who have herpes get blisters or soreson their lips, inside the mouth, or on the vagina or penis.
  • There is no cure for herpes so you have this STI for life, but there is medicine that can help you feel better and help prevent more outbreaks.


  • Human papillomavirus spreads from person to person through unprotected sex. 
  • Most people don’t know they have HPV but those with symptoms will experience genital warts (flat, cauliflower-like bumps that vary in size) on the vagina or penis.
  • HPV is the leading cause of cervical cancer in women. There is an effective HPV vaccine that can help protect girls and women. 


  • This STI is caused by a parasite.
  • Trichomoniasis is spread through body fluids during unprotected vaginal, or anal sex.
  • Anyone who’s sexually active can get it and pass it on. You don’t need to have lots of sexual partners.
  • Some symptoms include yellow or green discharge from the vagina, pain or burning when urinating, or pain or bleeding during sex.
  • It is treated using an antibiotic.

Check out this video to find out more about STIs:


  • This STI is caused by bacteria.
  • Gonorrhoea is usually passed from one person to another through sexual contact. You can get the infection if you come into contact with infected semen (cum or pre-cum) or infected discharge from the vagina, throat or rectum (back passage).
  • Gonorrhoea likes to live in warm and wet places, like the mouth, eyes, penis, vagina, or anus.
  • Common symptoms include: 
  • Discharge (a creamy liquid like pus) coming from your genitals
  • Needing to pee more often
  • Pain in your genitals, especially during sex
  • Sore throat
  • Fever
  • Can be treated with antibiotics.


  • HIV (Human Immunodeficiency Virus) is the virus that causes AIDS (Acquired Immunodeficiency Syndrome). 
  • HIV attacks the white blood cells and damages the immune system (the body’s system) which makes it hard for a person’s body to fight off infections.
  • If someone’s immune system is damaged by HIV, they may develop one or more serious infections and illnesses, called AIDS-defining illnesses.
  • You get HIV through contact with an infected person’s bodily fluids.
  • You can have virus for months or even years without feeling sick.
  • HIV cannot be cured but antiretroviral medication can make it undetectable in the body.


  • This STI is caused by bacteria.
  • It usually starts by causing painless sores or rashes on the skin, which can become serious if left too long.
  • Syphilis is easily spread by having oral, vaginal, or anal sex, or by kissing someone who has a syphilis sore on their mouth.
  • You can pass syphilis on without knowing you have it because symptoms can be mild and you may not notice or recognise them. It can also be passed on before symptoms are noticeable, or after they’ve disappeared.
  • This STI is treated using antibiotics.


  • Hepatitis B is an infection caused by a virus. It infects the liver.
  • If you come into contact with the bodily fluids of a person infected with hepatitis-B through unprotected oral, vaginal, or anal sex, you could get hepatitis B.
  • Many people don’t show symptoms but those who do show the following:
  • Yellow skin or eyes
  • No appetite 
  • Exhaustion
  • Brown or dark urine
  • Pain in the stomach
  • There is no cure for this STI but there is medication to help the liver 

If you think you may have an STI, you must go to your local clinic or doctor to get treated. Don’t wait! It may feel scary to tell your doctor or nurse but not getting treatment for an STI could mean bigger health problems for you. Many people don’t show symptoms when they have an STI which is why having sex with a condom is so important!

The only way to protect yourself against STIs if you are having sex is to ALWAYS use a condom. Learn how to use a condom correctly here

Did you know that you can get an STI from oral sex? Learn more

It can be scary to hear that your partner has an STI. Find out what steps to take in this article

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