Chlamydia is a common bacterial sexually transmitted infection (STI) that is curable with antibiotics. The infection, caused by the bacterium Chlamydia trachomatis, is often called “the silent infection” because most people do not experience symptoms. While the infection is not permanent, failing to treat it promptly can lead to serious, lasting health issues.
How Chlamydia Is Cured
The successful elimination of a Chlamydia infection relies on the proper use of prescription antibiotics. The preferred course of treatment for non-pregnant individuals is typically doxycycline, taken as a 100 mg pill twice a day for seven days. This regimen is highly effective at eradicating the active bacterial infection.
An alternative treatment option is a single, large dose of 1 gram of azithromycin, which may be selected when adherence to the full seven-day regimen is a concern. Regardless of the antibiotic chosen, it is important to complete the entire course exactly as prescribed. An infected person should avoid sexual contact until seven days after a single-dose treatment or until the completion of a seven-day course.
Following treatment, a test-of-cure may be recommended for pregnant individuals or those with a rectal infection to confirm the bacteria is completely gone. For most others, a retest is advised about three months after treatment, but this test primarily checks for a new infection. A successful course of antibiotics eliminates the active Chlamydia trachomatis organism, curing that specific infection.
Difference Between Recurrence and Reinfection
Once the Chlamydia bacteria has been successfully eradicated by antibiotics, the body is considered cured, but this cure does not grant future protection. After treatment, the immune system does not develop a strong, lasting immunity to Chlamydia trachomatis. This lack of protective immunity is why reinfection is common.
Reinfection occurs when a cured person is exposed to the bacteria again through a new sexual encounter with an infected partner who was not treated. This is a completely new event, distinct from the original infection. The risk of reinfection within 12 months is estimated to be between 10% and 20% in some populations.
Recurrence, in contrast, refers to a failure of the initial treatment to eliminate the bacteria, meaning the infection never fully cleared. True treatment failure is rare, with cure rates typically exceeding 95% when the antibiotics are taken correctly. The vast majority of positive tests following a cure are due to contracting a new infection.
Long-Term Health Consequences of Untreated Chlamydia
While Chlamydia is curable, the risk lies in allowing the bacterial infection to go untreated for an extended period. The bacteria can silently ascend into the upper reproductive tract, causing permanent damage before any noticeable symptoms appear. In women, this can lead to Pelvic Inflammatory Disease (PID), an infection of the uterus, fallopian tubes, and ovaries.
PID can result in chronic pelvic pain and scarring of the fallopian tubes. This scarring causes long-term complications, including tubal factor infertility and an increased risk of ectopic pregnancy. Approximately 10% to 15% of women with untreated Chlamydia will develop PID.
In men, untreated Chlamydia can cause epididymitis, inflammation of the coiled tube at the back of the testicle where sperm mature. This condition presents with pain and swelling in the testicles and can, in rare cases, lead to male infertility. Untreated infection in either sex can also trigger reactive arthritis, a painful joint inflammation that develops as a reaction to the infection.