Can You Have an STI Without Symptoms?

You feel completely fine. No discharge, no pain, nothing to point at. But a new partner, a condom that slipped or a friend's diagnosis has left you wondering whether you could have an STI anyway.

You can. Most STIs can cause no symptoms at all, and some of the most serious are the ones most likely to stay quiet. Chlamydia has no symptoms in roughly 70% of women and 50% of men (UKHSA, 2024; BASHH, 2024). Gonorrhoea is symptom-free in up to 50% of women, HPV almost never causes noticeable symptoms, and HIV can stay silent for years.

If you'd rather skip the reading and just get tested, walk in to our Harley Street clinic any day of the week. The Bronze Screen (£250) covers chlamydia, gonorrhoea, syphilis and HIV in one visit.

"Feeling well isn't the same as being clear. In our clinic, the majority of positive results come from patients who felt perfectly well. Screening after any new sexual contact is the single most effective way to protect yourself and your partners."

Dr Mohammad Bakhtiar, Clinical Lead, GMC 4694470

Which STIs are commonly asymptomatic?

An asymptomatic STI is an infection that is active and can be passed on, but causes no noticeable symptoms. Many of the commonest STIs in the UK behave this way, so routine screening is recommended for sexually active adults with new or multiple partners.

Chlamydia

Chlamydia is the most commonly diagnosed bacterial STI in England, and one of the most often silent. When symptoms do appear, they can include unusual discharge, pain when you pee or pelvic discomfort. For most people nothing feels different, and it's how people end up asking can chlamydia lie dormant when a positive result turns up years into a relationship.

Oral chlamydia is even less likely to cause symptoms, so throat infections go unnoticed unless a swab is taken.

Left untreated, chlamydia in women can lead to pelvic inflammatory disease (PID), ectopic pregnancy and infertility. In men, it can cause epididymitis and reactive arthritis.

Gonorrhoea

Gonorrhoea is more likely to cause symptoms in men than in women. Around 10% of men with urethral gonorrhoea have none, but in women the figure is 50% or higher. Throat (pharyngeal) and rectal gonorrhoea are symptom-free in most cases, whatever your sex.

When symptoms do appear, they usually include discharge and pain when urinating, and in women, bleeding between periods. If testing waited for symptoms, half of infected women would never come forward.

HPV (human papillomavirus)

HPV is almost always symptom-free. Most people who catch it clear the virus naturally within two years, without ever knowing they had it. The clinical concern is the small share of high-risk types (particularly 16 and 18) that persist and can cause cervical, anal or oropharyngeal cancer years later.

Low-risk types may cause genital warts, but the high-risk types linked to cancer produce no visible signs. HPV vaccination protects against the highest-risk types.

HIV

HIV can cause no symptoms for years after infection. Some people have a brief flu-like illness 2 to 6 weeks after exposure (acute seroconversion), but it's easily put down to a cold or a virus. After that, HIV can stay clinically silent for a decade or more while it gradually damages the immune system.

This is where the accuracy of early HIV testing comes in. A 4th generation HIV test (antigen/antibody) can detect infection from 28 days after exposure (BASHH, 2024). For earlier detection, RNA PCR testing is available from 10 days.

Herpes (HSV-1 and HSV-2)

Herpes often causes no symptoms, or symptoms so mild they go unnoticed. Many people with genital herpes have never had a recognisable outbreak. The WHO estimates that two-thirds of the global population under 50 carries HSV-1, most of them without knowing.

Herpes spreads mainly through asymptomatic shedding, when the virus is released from skin that shows no sores. It keeps spreading widely even though many carriers never have symptoms.

Syphilis

Syphilis is unusual because its symptoms go away without treatment. The first stage brings a painless sore (chancre) that heals on its own within 3 to 6 weeks. The second stage causes a rash that also clears by itself. Syphilis then enters a latent phase that can last years with no symptoms, while the infection keeps damaging internal organs.

Syphilis rates in England have been rising since 2012. Because the first sore is painless and heals by itself, many people never notice it.

Hepatitis B and C

Hepatitis B causes no symptoms in many adults during acute infection, and chronic carriers may have none for decades. Hepatitis C is similar. Around 80% of people with acute hepatitis C have no symptoms, and chronic infection can quietly damage the liver over 20 to 30 years.

Trichomoniasis

Trichomoniasis causes no symptoms in about 50% of women and in most men. When symptoms do appear, they include vaginal odour, discharge and vulval irritation.

How many people have an STD without knowing?

These aren't edge cases. For most STIs, having no symptoms is the norm.

When is it worth testing if you feel fine?

If you've had a new sexual partner in the past 12 months and haven't been tested since, a screen is sensible however well you feel.

If you've had unprotected sex, including oral sex, a silent infection is a real possibility. Tell your clinician every site that was exposed. A urine test covers genital infections, and the throat or rectum each need a swab.

If a current or previous partner has tested positive, come and get tested even if you have no symptoms. Chlamydia and gonorrhoea in particular pass between partners without either of them noticing.

If you're starting a new relationship, testing gives you both a clean baseline. It's one of the most practical reasons to screen, and the least emotionally loaded.

For most of these situations, the Bronze Screen (£250) is the place to start: chlamydia, gonorrhoea, syphilis and HIV. The Silver Screen (£325 men, £375 women) adds mycoplasma, trichomoniasis, ureaplasma, Gardnerella, herpes, and a bacterial swab for women.

What happens when you come in

Walk-in STI testing is available seven days a week at our Harley Street clinic, with no appointment or GP referral needed. All samples are processed by UKAS-accredited laboratories. You don't need to use your real name, and we accept cash payment.

Depending on the package and your exposure, we take blood, urine and swabs. Results for blood tests come back in about 24 hours, and urine and swab results within 3 working days.

If you need same-day STI results, our FAST Screen Simple (£350) returns chlamydia, gonorrhoea, syphilis and HIV results within 6 hours. The FAST Screen Complex (£450) adds hepatitis B and C, with all results also back in 6 hours.

If anything comes back positive, our doctors can prescribe treatment the same day.

References

• UKHSA (2024). Sexually transmitted infections and screening in England: 2023 report.
• BASHH (2024). UK National Guideline for the Management of Genital Tract Infection with Chlamydia trachomatis.
• BASHH (2024). UK National Guideline for the Management of Gonorrhoea in Adults.
• WHO (2024). Herpes simplex virus: key facts.
• NICE CKS (2024). Chlamydia: uncomplicated genital.