Chlamydia

Chlamydia is a bacterial infection passed on through sex. It's the most common STI in the UK, especially among young people. The tricky thing about chlamydia is that most people who have it don't get any symptoms — so you can have it and pass it on without knowing.

• Chlamydia is the most common STI in the UK — it's especially common in under-25s.
• Most people with chlamydia have no symptoms at all.
• Testing is quick and easy — usually just a urine sample or a swab.
• It's cured with a short course of antibiotics.
• If left untreated, it can cause serious problems including fertility issues.

How you get it

Chlamydia is passed on through unprotected vaginal, anal, or oral sex with someone who has it. It can also be passed on by sharing sex toys that haven't been washed or covered with a new condom between uses. You can't catch it from kissing, hugging, sharing towels, or using the same toilet.

Using condoms every time you have sex significantly reduces the risk. But because chlamydia is so common and so often has no symptoms, regular testing is the best way to stay on top of it if you're sexually active.

Symptoms (when they show up)

Most people with chlamydia don't notice anything — around 70% of people with a vagina and 50% of people with a penis have no symptoms. When symptoms do appear, they might include:

• Unusual discharge from the vagina, penis, or anus
• Pain or burning when you pee
• Pain in the lower belly (for people with a uterus)
• Pain or swelling in the testicles (for people with a penis)
• Bleeding between periods or after sex

Symptoms can take weeks to show up, or they might never appear at all. That's why waiting for symptoms before getting tested doesn't work — the infection can be there doing damage without you feeling a thing.

Why it matters if it's untreated

If chlamydia isn't treated, it can lead to more serious problems. In people with a uterus, it can cause pelvic inflammatory disease (PID), which can damage the fallopian tubes and lead to fertility problems or ectopic pregnancies. In people with a penis, it can cause epididymitis (painful swelling in the tubes next to the testicles), which can also affect fertility in rare cases.

The good news is that all of this is avoidable. A simple test catches it, and a short course of antibiotics clears it up.

Getting tested

Testing for chlamydia is straightforward. It's usually a urine sample (you pee in a pot) or a swab — you can often do the swab yourself. Results come back within a couple of weeks, sometimes faster.

In the UK, you can get tested for free at:

• Sexual health clinics (GUM clinics)
• Your GP
• Some pharmacies
• Online — free postal test kits are available through the NHS in many areas

If you're under 25, the NHS National Chlamydia Screening Programme means you can get tested easily and often — it's specifically set up for your age group.

Things people get wrong

"I'd know if I had it." Probably not. Most people with chlamydia have zero symptoms. The only way to know is to test.

"It's a big deal to have an STI." Chlamydia is incredibly common and very treatable. Having it doesn't mean you've done something wrong — it means you've been sexually active and a bacteria got passed on. That's it.

"You can only get it from penetrative sex." Chlamydia can also be passed through oral sex and through sharing sex toys, though these are less common routes.

Things people ask about chlamydia

Can chlamydia go away on its own?

Sometimes the body can clear it, but you shouldn't count on that — untreated chlamydia risks serious complications. Antibiotics clear it quickly and reliably.

Do I have to tell my partner?

If you test positive, your recent sexual partners need to know so they can get tested and treated too. The clinic can help with this — including sending anonymous notifications if you don't want to do it directly.

Can I get chlamydia again after being treated?

Yes. Being treated doesn't make you immune. If you have sex with someone who has it, you can catch it again. That's why regular testing and condoms both matter.

How soon after sex should I get tested?

Chlamydia can take up to two weeks to show up on a test. If you test too early, you might get a false negative. Two weeks after the potential exposure is usually the advice, though a clinic can tell you what's best for your situation.

Where to get help

• Sexual health clinics (GUM clinics) — free, confidential testing and treatment. No GP referral needed.
• SH:24 / Fettle — free NHS-funded postal STI testing kits you do at home. [CHECK: regional availability]
• Brook — sexual health services and advice for under-25s.

Chlamydia is an infection caused by bacteria. You can catch it by having sex with someone who has it. It's the most common sexually passed infection in the UK, and it's especially common in young people.

The tricky thing is that most people with chlamydia don't feel anything at all. You can have it without knowing. That's why getting tested is so important, even if you feel fine.

Some people do get signs, like pain when they wee, unusual stuff coming from between their legs, or tummy pain. But most people get no signs at all.

If chlamydia isn't treated, it can cause serious problems inside the body over time, especially with being able to have babies later in life. But the good news is it's very easy to fix. You take antibiotics for a few days and it's gone.

Getting tested is simple. You usually just wee in a pot or do a swab yourself. It's free at sexual health clinics, your doctor, and sometimes through home testing kits sent in the post.

Using condoms helps stop it spreading. If you find out you have it, the people you've had sex with need to know so they can get tested too. The clinic can help with that.