Skip to main content

What are sexually transmitted infections (STIs)?

Sexually transmitted infections (STIs) are infections that can be passed on during unprotected sex and intimate skin-to-skin contact. 

Using a condom is the best way to prevent most STIs.  

Many STIs don’t have any symptoms. This means you can have an STI without knowing it and pass it on to your partner during sex or close contact. Most are easily treated, especially when they are discovered early. If left untreated, STIs can lead to serious health problems 

If you’re having sex it’s important to have regular STI checks – even if you don’t have any symptoms. Getting tested and treated will keep you and your sexual partner(s) healthy.  

What are sexually transmitted infections (STIs)?

Sexually transmitted infections (STIs) are infections that can be passed on during sex. They are caused by bacteria, viruses or parasites. They are most commonly spread through unprotected vaginal, anal and oral sex, and sharing sex toys.  

Skin-to-skin genital contact can also spread some STIs. These include gonorrhoea, syphilis, HPV, herpes, genital warts, pubic lice and chlamydia.

What are the most common symptoms of STIs?

Many people have no symptoms when they have an STI, or their symptoms might be very mild or only appear several weeks after infection. This means it’s very common to have an STI without realising it.  

When people do have symptoms these can include:  

  • sores/soreness  

  • unusual lumps  

  • itching 

  • pain when urinating (peeing) or defecating (pooing) 

  • unusual discharge from the genitals. 

If you notice any symptoms or think you are at risk you should see a healthcare professional as soon as possible. Do not have sex, including oral sex, until you have had a sexual health check-up. 

How do I prevent STIs?

Using condoms and dental dams makes sex safer and prevents many STIs (but not all). Always cover sex toys with a condom too (a new one for each person) and wash toys after use.  

As many people will have no STI symptoms, the best way to look after your health if you are sexually active is to have regular sexual health check-ups. This is especially important before and after unprotected sex or sexual activities with a new partner. 

See full details for this resource

How do I get tested for STIs?

You cannot diagnose an STI by yourself as symptoms vary from person to person. Only a healthcare professional can diagnose an STI. You shouldn’t feel embarrassed going for a check-up, they’re a normal part of looking after your health. 

If you're worried you might have an STI you should go for a check-up with a health professional as soon as you can. You shouldn’t have sex, including oral sex, until you've had a sexual health check-up. 

If you test positive for one STI you should get tested for other STIs including HIV

What’s involved in STI testing and how long does it take?

Having a sexual health check-up can involve tests. This could be a genital examination, a genital or oral swab for bacteria, a urine sample or a simple blood test. Testing is usually free in government run clinics but paid for in private health facilities. You’ll get some results straight away, other results will take up to two weeks. 

There are some tests that are available to do at home using a self-test kit, but you should always get advice from a healthcare professional first. They can help you decide which kit is best for you and tell you how to use it. 

Is there a cure for STIs?

Most STIs can be cured with the correct treatment. A few cannot be cured, but can be managed with treatment. If you have an STI, getting treatment early is the best way to look after your health and protect your sexual partner(s). 

Antibiotics or creams cure many STIs. Longer lasting infections can be managed by other treatments, such as antiviral drugs for Hepatitis C. If you have an STI, it’s important to tell any current or recent sexual partners, as they will need to test too.  

Let's talk about STIs!

Here are a few questions to help kick-off discussions on the issues you need to talk about! You can share them on social, on WhatsApp or just get talking.

Talking about STIs
See full details for this resource
See full details for this resource

Test your knowledge of STIs

STIs quiz

Join the conversation

Looking for more detailed information?

Does having an STI make me more at risk of getting or passing on HIV?

Having an STI, especially one that causes sores, makes it easier for HIV to get into your body and cause an infection. If you have been diagnosed with an STI you should also test for HIV.  

If you are HIV-positive and not on treatment (or have a lower CD4 count) then having an STI will increase your viral load. This means you are more likely to pass on HIV if you have sex without a condom.

If you have an undetectable viral load, there’s no evidence that an STI will make you more likely to pass on HIV. 

Is someone with HIV more likely to get an STI?

Yes. People with HIV can be more likely to get an STI.  

This is especially the case for people who aren’t on treatment or who have a lower CD4 count. You’re more vulnerable to infections if your immune system is weaker. STIs may also progress more quickly in people with HIV. If you have HIV and think there’s a chance you might have an STI it’s important to get tested and treated early on. 

If you have HIV make sure you speak to a healthcare provider. They can ensure that any medication you take for an STI won’t affect your antiretroviral treatment (ART). 

Join the conversation

Share this page

  • Last updated: 04 April 2024
  • Last full review: 01 March 2022
  • Next full review: 01 March 2025
Did you find this page useful?
See what data we collect and why