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What is chlamydia?

Chlamydia is a Sexually Transmitted Infection (STI or STD) caused by a bacteria. It is the most commonly reported contagious disease in Boston. Chlamydia is usually treated with one dose of antibiotic. If left untreated, it can lead to infertility and Pelvic Inflammatory Disease in women.

How do I get chlamydia?

Chlamydia is spread through vaginal fluids or semen during vaginal, anal or oral sex with an infected person. Chlamydia can also be passed from mother to child during birth.

What are the symptoms of chlamydia?

Most people do not have symptoms. Symptoms may start about 1-3 weeks after being infected. For those who do have symptoms, the most common are:

For Women:
  • Unusual discharge (yellowish or whitish fluid) from her vagina
  • Pain and/or burning when she pees or during sex
  • Pain in the stomach or back
  • Bleeding even when it's not her period
  • In more serious infections, fever

For Men:
  • Unusual discharge (thick white or watery fluid) coming from the penis
  • Pain and/or burning when he pees
  • Less common symptoms include:
  • Heavy feeling and/or pain in the testicles
  • Pain, swelling or redness around the scrotum

Men and women can also get infected with chlamydia in their rectum, either by having receptive anal sex, or by spread from another infected site (such as the vagina). While these infections often cause no symptoms, they can cause rectal pain, discharge and/or bleeding from the rectum.

REMEMBER: most people with chlamydia don't have symptoms!

How long can an infected person spread chlamydia?

A person can spread chlamydia to others by having unprotected anal, vaginal or oral sex. An infected person can spread the infection from the time they became infected until they are treated. A person can spread chlamydia even if they do not have symptoms.

How can I find out if I have chlamydia?

The only way to know for sure if you have chlamydia is to get tested. You will need to provide a urine sample or a swab from the infected site (such as a vagina or penis) to test for chlamydia. Call the Mayor's Health Line at (617) 534-5050 if you need help finding health care. Learn more about when and where to get tested by visiting

The Centers for Disease Control and Prevention recommends yearly chlamydia testing for:
  • All sexually active men and women under 25
  • People at high risk, including:
  • Those who have had unprotected sex
  • Those who have had sex with multiple partners or sex with a new partner

You should also get tested:
  • When you are pregnant
  • 3 months after treatment for a Sexually Transmitted Infection       
  • Every time you have a new partner if you are unsure of the partner's status
Where can I get tested?

Most health care providers offer testing for chlamydia and other STIs. To find health care near you, call the Mayor's Health Line at 617-534-5050 (Toll-Free: 1-800-847-0710). You can also visit

Can chlamydia be treated?

Yes.  A single dose of antibiotics usually cures chlamydia. You should be tested again about three months after you are treated to make sure you are no longer infected. Alternative treatments are available if you are allergic to the medicine usually prescribed.

Should my partner get treated?

Yes. Recent sex partners must be treated before having sex again. You can get chlamydia many times, so you might be re-infected if you have sex with an untreated partner. Massachusetts law allows partners of patients with chlamydia to be treated without needing to be tested. Ask your health care provider about this during your visit. For more information, check out the Expedited Partner Therapy fact sheet available at

What happens if chlamydia is not treated?

If left untreated, chlamydia can cause very serious health problems.  Women can develop Pelvic Inflammatory Disease (PID), which can cause infertility (unable to have children). Chlamydia can also increase your chances of getting other sexually transmitted diseases, such as HIV or gonorrhea. 

Do the following to limit your risk of an STI:
  • Use a latex or polyurethane condom or barrier (dental dam) EVERY TIME you have anal, vaginal and/or oral sex.
  • Condoms made from "natural" materials may protect against pregnancy but NOT STIs.
  • ONLY condoms prevent STIs or HIV, other forms of birth control DO NOT.
  • Limit your number of sex partners – the more partners you have, the more likely you will get chlamydia.
  • Talk with your partner about their STI status and getting tested.
  • Talk with your health care provider about safer sex and getting tested.
  • Remember that drugs and/or alcohol can make it more likely that you won't use a condom if you have sex.
  • Contact your health care provider if you experience any symptoms.
Abstinence is the only sure way to prevent STIs and pregnancy.
Boston Public Health Commission
1010 Massachusetts Ave, 6th Floor, Boston, MA 02118.
Phone:(617) 534-5395 Email: