Chlamydia is the most common curable sexually transmitted infection (STI). The World Health Organisation estimates that there were about 129 million new infections worldwide in 2020 WHO. Germany has no mandatory reporting system, so precise figures are lacking; specialists estimate roughly 300,000 cases per year RKI estimate. The problem is that most people notice no symptoms, allowing complications such as infertility to develop unseen.
Chlamydia Explained: Causes & Transmission
The infection is caused by the bacterium Chlamydia trachomatis, which targets the mucous membranes of the urethra, cervix, rectum, and throat. Transmission is almost always via unprotected vaginal, anal, or oral sex. During childbirth, an infected mother can also pass the bacterium to her baby, leading to conjunctivitis or pneumonia in newborns.
Symptom Check: How “Silent” Is Chlamydia?
According to the CDC, infections are asymptomatic in around 70–95 percent of women and about 50 percent of men. When symptoms do occur, they usually appear one to three weeks after exposure – by then the bacteria may have spread further.
Chlamydia in Women – Typical Symptoms & Long-Term Effects
Early warning signs (if any):
- unusual, often watery-pus–like or foul-smelling discharge
- inter-menstrual or post-coital bleeding
- pain during intercourse (dyspareunia)
- burning when passing urine (dysuria)
- lower-abdominal or back pain
Potential long-term consequences if untreated:
- PID (pelvic inflammatory disease) – infection spreading to the uterus and fallopian tubes
- Salpingitis – scarring of the tubes leading to blockage
- Infertility – reported in up to 40 percent of untreated cases
- greater risk of ectopic pregnancy, pre-term birth, or miscarriage
Chlamydia in Men – What’s Different?
Possible acute symptoms:
- clear to pus-like urethral discharge
- burning or pain when urinating
- swelling or pain in the testes or epididymis
Typical complications (rare but possible):
- Epididymitis – inflammation of the epididymis with pain and fever
- prostatitis or urethral strictures
- reduced sperm quality, leading to fertility issues
- Reactive arthritis (Reiter’s syndrome) – inflammation of joints, eyes, and skin
Note: Even men without symptoms can transmit the infection – both partners must always receive treatment.
Untreated Chlamydia: Shared Risks
- chronic pelvic or lower-abdominal pain
- infertility in women; reduced fertility in men
- conjunctivitis or pneumonia in newborns
Prevention That Really Works
- Condoms – highly effective when used consistently and correctly
- Routine testing – the CDC advises annual screening for sexually active women up to 25 and risk-based testing thereafter
- limit the number of sexual partners or agree on shared testing intervals
- clean sex toys after each use or cover them with a fresh condom
- pregnant individuals should be tested for chlamydia in the first trimester
Treatment Today – Why Doxycycline Has Replaced Azithromycin
Chlamydia is almost always curable with antibiotics. Updated guidelines favour doxycycline for seven days over a single dose of azithromycin because studies show rising azithromycin resistance and slightly better efficacy for doxycycline. Proven laboratory resistance to tetracyclines or macrolides is still very rare.
Diagnostics & Testing Basics
Test types
- NAAT / PCR – highly reliable; results within one to two days
- Rapid test – result in about 20 minutes, but far less accurate (screening only)
Specimen options
- women: vaginal swab (self-taken or clinician) or first-catch morning urine
- men: first-catch urine; urethral swab if symptomatic
When to Seek Medical Advice
The WHO defines infertility as the absence of pregnancy after twelve months of unprotected intercourse (after six months if the woman is over 35). Common causes include untreated chlamydia, endometriosis, and hormonal disorders.
- unexplained discharge, burning, or bleeding — get tested straight away
- new relationship without up-to-date STI status — both partners should test
- positive result — treat both partners and abstain from sex for seven days
Take-Home Message
Chlamydia is common, often silent – yet highly treatable. Regular testing, consistent condom use, and prompt antibiotics greatly reduce the risk of serious complications such as infertility. Invest in your sexual health – preventing infection is far easier than dealing with long-term damage.