The Facts About Chlamydia and HIV

Common Sexually Transmitted Infection May Increase HIV Risk

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Each year, there is roughly 1.2 million cases of chlamydia in the U.S., according to the Centers for Disease Control and Prevention. Many experts, however, believe that this common sexually transmitted infection is substantially under-reported, due to the lack of obvious signs and symptom in many infected individuals.

What is Chlamydia?

Chlamydia has an infection rate in women similar to that of gonorrhea.

Chlamydia is caused by the bacteria Chlamydia trachomatis. Like gonorrhea, chlamydia can cause pelvic inflammatory disease and infertility.

Diagnostic testing for chlamydia infection is widely available in many developed countries. However, the test for chlamydia is costly and not generally available in developing countries. This means that in many parts of the world, chlamydia infections go undetected and therefore untreated.

How Does Chlamydia Infection Occur?

Chlamydia is spread from person to person during unprotected anal, vaginal, or oral sex. It can also be passed from mother to newborn baby during vaginal childbirth.

While any sexually active person is at risk for infection, some people have a higher risk than others. They include:

  • Teenage girls, who have a higher risk because their cervix is not yet fully matured. (By contrast, chlamydial infections are seen less frequently in older women, but they can and still do occur.)

The Facts About Chlamydia and HIV

Any sexually transmitted infection has the potential to increase HIV risk. The reasons for this are twofold.

Firstly, the infection can cause genital inflammation which can undermine the integrity of the mucosal tissue that line the vagina, cervix, and rectum.

This provides HIV a more direct route into the bloodstream and lymphatic system.

Secondly, an active chlamydial infection can increase the HIV viral activity around the genitals. When this happens, a person can potentially have an undetectable viral load in blood test but a detectable viral load in semen or vaginal secretions.

Some studies have suggested that chlamydia infections have been noted in as many as 15% of MSM newly infected with HIV.

What Are the Signs and Symptoms of Chlamydia?

About 75% of women and 50%of men who have chlamydia have no symptoms. But if symptoms do appear, they generally do so about one to three weeks after exposure.

The most common symptoms in women include:

  • vaginal discharge
  • burning or pain with urination
  • abdominal and/or low back pain
  • nausea
  • fever
  • pain with intercourse
  • vaginal bleeding between periods

The most common symptoms in men include:

  • burning or pain with urination
  • penile discharge
  • burning and itching at the tip of the penis
  • swollen and painful testes

If left untreated, chlamydia can cause permanent damage to the reproductive system in both males and females.

These events often occur without any outward symptoms.

How is Chlamydia Treated?

Fortunately, treatment of chlamydia is easy and effective. A variety of antibiotics taken for various lengths of time will successfully treat a chlamydia infection. These antibiotics include:

  • Azithromycin, taken in a single oral dose
  • Doxycycline, taken over a seven-day course
  • Erythromycin
  • Amoxicillin

Keep in mind that that all doses of the prescribed antibiotic must be taken, even if the person is feeling better or is symptom-free. Sexual activity must be avoided during treatment, and all sexual partners must be tested and treated.

Women and teenage girls should be re-tested a few months after completion of treatment. Because of the risk of reinfection and the potential harm chlamydia can do to the reproductive system, it is important to confirm that the infection has been completely eradicated.


Centers for Disease Control and Prevention. "Sexually Transmitted Disease Surveillance, 2008"; Atlanta, Georgia; U.S. Department of Health and Human Services, November 2009.

National Institute of Allergy and Infections Diseases; "Chlamydia Fact Sheet"; National Institutes of Health; 10 Nov 2010.

Xiridou, M.; Vriend, H.; Lugner, A.; et al. "Modelling the impact of chlamydia screening on the transmission of HIV among men who have sex with men." BMC Infectious Diseases. 2013; 13(436):DOI: 10.1186/1471-2334-13-436.

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