Chlamydia is an STI caused by bacteria and passed through vaginal, anal, or oral sex.

It can be found in the genitals, rectum, or throat, and often doesn’t cause any symptoms, so you might not know you have it.

When symptoms do appear, they can include discharge that is not normal for you. It can also cause pain when peeing, or pain during sex. Some people may also experience lower stomach pain or bleeding between periods.

Because chlamydia is a bacterial infection, it can be present in one part of the body and not others. For example, it can be in the throat from oral sex or in the rectum from anal sex without affecting the genitals.

This is why it’s important to be open about the types of sex you’re having when you get tested. It helps make sure the right areas are tested so infections aren’t missed.

If chlamydia isn’t treated, it can lead to serious complications. These can include pelvic inflammatory disease, pain and swelling in the testicles, and in some cases, it can affect fertility.

The good news is that chlamydia is easy to treat with antibiotics. Treatment is free and it’s usually quick and very effective.

Gonorrhoea is becoming more common in young people. Like chlamydia, it’s a bacterial STI that can be passed through vaginal, anal, or oral sex, and often has no symptoms.

It can be found in the genitals, rectum, or throat. That’s why it’s important to be open about the types of sex you’re having when you get tested. This helps make sure the right areas are tested and infections aren’t missed.

When symptoms do appear, they can include discharge that is normal for you. It may also cause pain when peeing, or discomfort in the lower stomach or testicles. 

If it isn’t treated, gonorrhoea can cause serious health problems. This can include infections in parts of the reproductive system, like the womb, fallopian tubes and ovaries. It can also cause pain or swelling in the testicles. In some cases, it can affect fertility.

Gonorrhoea is treated with antibiotics, and treatment is usually straightforward. However, some types of gonorrhoea are becoming harder to treat because antibiotics are not always as effective. This is known as antibiotic resistance. It’s important to get tested and treated early to stop it spreading and reduce the risk of complications.

Syphilis is less common than chlamydia or gonorrhoea. However, cases have been increasing in recent years.

Syphilis develops in stages. It often starts with a painless sore, usually on or around the genitals, anus, or mouth. Sores can be small and easy to miss and usually heal on their own within a few weeks.

A few weeks later, a second stage can develop. Symptoms can include a rash (usually on the hands or feet), flu-like symptoms, swollen glands, or patchy hair loss. These symptoms can go away on their own without treatment.

Even if symptoms disappear, the infection stays in the body.

If it isn’t treated, syphilis can remain hidden for years. After some time, it can cause serious health problems affecting the brain, heart, nerves, and other organs.

Many people don’t notice the symptoms in the early stages. A simple blood test is all that is required for testing. If you have an ulcer, then a sample may be taken from that ulcer.

Syphilis is treated with antibiotics, usually as a course of injections. Treatment is very effective. If it’s started early, it can stop the infection from causing long-term health problems.

Genital herpes is caused by a virus that spreads through skin-to-skin contact. This can include vaginal, anal or oral sex.

It can cause small blisters or sores around the genitals, anus or mouth. Some people have noticeable outbreaks, whilst others have very mild symptoms, or no symptoms at all.

There are two main types of the virus: HSV-1 and HSV-2.

HSV-1 is often linked to cold sores around the mouth, but it can also be passed to the genitals through oral sex.

HSV-2 more commonly affects the genitals. This means that a cold sore can be passed on during oral sex and cause genital herpes.

Herpes can sometimes be passed on even when there are no visible sores. The risk of passing on herpes is higher when symptoms are present. After the first infection, the virus stays in the body and can become active again from time to time.

There isn’t a cure for herpes, but antiviral medication can help manage symptoms and speed up healing. It can also reduce how often outbreaks happen.

Some people take treatment only when symptoms appear. Others take it regularly to reduce the risk of passing it on. People with herpes can live normal, healthy lives.

HPV is very common. Most sexually active people will come into contact with it at some point.

In many cases, HPV causes no symptoms and goes away on its own. Some types can cause genital warts. Other types are linked to certain cancers later in life.

The HPV vaccine helps to protect you against the types most commonly linked to cancer and genital warts. If you missed the HPV vaccine in school you can get it for free, just speak to your GP.

If you have a cervix and are aged 25 or over, you will also be invited for regular cervical screening (smear tests). This helps detect changes caused by HPV early, and can prevent cervical cancer or catch it early.

HIV is a virus that affects the immune system. It can be passed on through unprotected vaginal or anal sex, sharing needles, or through blood.

The risk of passing on HIV through oral sex is much lower than through vaginal or anal sex, but it is not zero.

It cannot be passed through kissing, hugging, sharing food, or using the same toilet.

Some people experience flu-like symptoms shortly after getting HIV. However, many people have no symptoms at first. The only way to know for sure is to get tested.

There is currently no cure for HIV, but it can be managed very effectively with medication. People living with HIV, who take treatment and have an undetectable viral load, cannot pass the virus on through sex. This is known as U = U (Undetectable = Untransmittable).

With the right treatment, people living with HIV can live long, healthy lives.

Find out more about HIV and how to protect yourself.