How Do You Get Chlamydia? How It Spreads and How to Protect Yourself

You had unprotected sex, or a partner just told you they tested positive, and now you are anxious and googling at 2 a.m. Take a breath. Chlamydia is one of the most common infections out there, it is easy to test for, and it is curable with antibiotics. Understanding exactly how it spreads is the first step to protecting yourself and getting the care you need.

Here is the short answer: you get chlamydia from unprotected vaginal, anal, or oral sex with someone who carries the bacteria. Below, we break down how transmission really works, why so many people never know they have it, and what to do next.

How do you get chlamydia?

Chlamydia is caused by a bacterium called Chlamydia trachomatis, and it spreads through sexual contact. You can get it through unprotected vaginal, anal, or oral sex with a partner who has the infection. Importantly, ejaculation does not have to happen for chlamydia to pass from one person to another, so any genital contact with an infected partner carries risk.

Chlamydia can also be passed from a pregnant person to their baby during vaginal childbirth, where it can cause eye infections (neonatal conjunctivitis) or pneumonia in the newborn. It is not spread through casual contact like hugging, sharing food, toilet seats, or swimming pools.

• Unprotected vaginal sex with an infected partner
• Unprotected anal sex with an infected partner
• Unprotected oral sex with an infected partner
• From a pregnant person to their baby during vaginal delivery

Why so many people don't know they have it

One of the trickiest things about chlamydia is that it is usually silent. It is asymptomatic in roughly 70% of infected women and about 50% of infected men, which means most people carrying it have no idea. That is exactly why it spreads so easily: you can pass it to a partner, or catch it from one, without either of you noticing anything wrong.

Because it so often hides, chlamydia is the most commonly reported bacterial sexually transmitted infection in the United States. The CDC estimates about 2.86 million chlamydia infections occur each year in the U.S., though fewer than half are actually reported, largely because so many cases never cause symptoms. This is the core reason that routine screening matters even when you feel completely fine.

How long after exposure do symptoms show?

When chlamydia does cause symptoms, they typically start 5 to 14 days after exposure, according to Mayo Clinic. But remember that many infections cause no symptoms at all, and when they do, signs can be easy to miss or mistake for something else. Symptoms can also take several weeks to appear, which makes it hard to pin down exactly when or from whom you got it.

Possible symptoms to watch for include:

• Painful urination
• Abnormal discharge from the vagina or penis
• Lower abdominal pain
• Pain during sex and bleeding between periods (in women)
• Testicular pain or swelling (in men)

Can you get chlamydia more than once?

Yes. Having had chlamydia and being treated does not make you immune. A prior treated infection does not give you lasting protection, so you can be reinfected if you have unprotected sex with an infected partner again, including the same partner if they were not treated at the same time.

This is why doctors usually recommend that all recent partners get tested and treated, and why many clinicians suggest retesting a few months after treatment. Treating both partners and avoiding sex until everyone has completed treatment is the best way to avoid a repeat infection.

How to lower your risk

You cannot always tell whether a partner has chlamydia, because it so often causes no symptoms. The most reliable prevention is abstinence, or a mutually monogamous relationship with a partner who has tested negative. Short of that, condoms and regular testing make a real difference.

According to the CDC, latex condoms used consistently and correctly reduce the risk of chlamydia transmission. Routine screening also helps, because chlamydia is widespread in the general population, not just in high-risk groups. A meta-analysis found the pooled global prevalence of genital chlamydia in the general population is about 2.9%, slightly higher in women (3.1%) than men (2.6%).

• Use latex condoms consistently and correctly for vaginal, anal, and oral sex
• Get tested regularly if you are sexually active, even without symptoms
• Make sure recent partners are tested and treated
• Avoid sex until you and your partner have finished treatment

When to see a doctor or get tested

Get tested if you have had unprotected sex, a partner tells you they tested positive, or you notice any symptoms like unusual discharge, painful urination, or pelvic pain. Because chlamydia is so often silent, sexually active people, especially younger adults, benefit from routine screening even when they feel fine.

Left untreated, chlamydia can lead to serious problems, including pelvic inflammatory disease, ectopic pregnancy, and infertility in women, and epididymitis in men. The good news is that chlamydia is curable with antibiotics prescribed by a clinician. If you think you may have been exposed, the safest move is a simple, confidential test and a conversation with a healthcare provider who can guide treatment for you and your partner.