References UK clinical guidance from the NHS, the British HIV Association (BHIVA), and the British Association for Sexual Health and HIV (BASHH). Last updated: April 2026.
Many STIs cause no symptoms at all, especially in the early stages. This is why they’re called “silent” or “asymptomatic” infections. Despite causing no symptoms, they can still damage the body, pass to partners and cause long-term complications. Regular testing is the only reliable way to catch them.
Here’s what to know about silent STIs.
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STIs That Are Often Silent
| STI | Percentage With No Symptoms |
|---|---|
| Chlamydia | Up to 70-80% |
| Gonorrhoea (women) | Up to 50% |
| Gonorrhoea (men) | Up to 10% |
| Trichomoniasis | Up to 50% |
| HIV (for years after infection) | Most people |
| HPV | Most infections |
| Herpes (first few years) | Many people |
| Syphilis (latent stage) | Everyone |
| Hepatitis B and C | Often silent for years |
| Mycoplasma genitalium | Many people |
Why Silent Doesn’t Mean Harmless
- Complications still develop — infertility, pelvic pain, cancer, liver damage
- Transmission continues — you can pass the infection to partners
- Treatment is still effective — catching silent infections allows full treatment
- Long-term damage — untreated infection builds up over time
Examples of Silent Damage
- Chlamydia — can cause pelvic inflammatory disease and infertility with no noticeable early symptoms
- HPV — persistent infection can lead to cervical, anal or throat cancer years later
- HIV — gradually destroys the immune system over years before symptoms appear
- Hepatitis B and C — cause liver damage silently for decades
- Syphilis — can hide in the body for years, then cause serious complications in the heart or brain
Why Regular Testing Matters
Since you can’t rely on symptoms to tell you if you have an STI, testing is the only way to know. Recommended screening:
- Sexually active adults — at least annually
- New partner — test after each new partner
- Multiple partners — every 3-6 months
- MSM at higher risk — every 3 months
- Young people under 25 — annual chlamydia screening
What a Full Screen Should Include
- Chlamydia and gonorrhoea (urine or swab, including throat and rectal if relevant)
- HIV (4th-generation test)
- Syphilis (blood test)
- Hepatitis B (and hepatitis C if indicated)
- Sometimes trichomoniasis and mycoplasma genitalium
Where to Get Tested
- NHS sexual health clinics (free, confidential, walk-in)
- Home test kits (free in many areas)
- GP surgery
- Online postal services
Read more: Home STI tests | When to test | Common STI symptoms in women
Frequently Asked Questions
How common are silent STIs?
Very common. Chlamydia is silent in up to 80% of cases. Many other STIs have no symptoms for long periods.
If I feel fine, do I still need to test?
Yes. Feeling fine doesn’t rule out infection. Regular testing is the only reliable way to catch silent STIs.
Can I pass on an STI I don’t know I have?
Yes. This is why silent STIs continue to spread and why regular testing is so important for sexual health.
Related reading
- Abnormal Genital Discharge and Chlamydia
- Causes of Painful Sex and How to Treat It
- Cold Sores vs Syphilis Sores: How to Tell the Difference
- Common STI Symptoms in Women
- Do STIs Always Have Symptoms?
Sources
- NHS — Sexual health conditions
- BASHH — UK clinical guidelines for STI management
- British HIV Association (BHIVA) — HIV treatment guidelines
- Terrence Higgins Trust — sexual health information
- UK Health Security Agency — STI surveillance data
Steve Page is a recognised expert on Sexually Transmitted Diseases (STDs) and STD treatments, having published numerous articles in peer-reviewed journals and presented his research at conferences around the world. He has an in-depth understanding of the latest medical research on STDs, and is an advocate for the development of new treatments and protocols to improve the health of those affected. In addition to his research, he has dedicated his career to understanding the causes and symptoms of STDs, as well as how to best treat those impacted.
