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.
The short answer: it’s extremely unlikely for most STIs, but not impossible for all. The infections most people worry about, like chlamydia, gonorrhoea, and HIV, cannot realistically be transmitted through shared underwear. However, pubic lice (crabs) and scabies can be passed through shared clothing and bedding, and there’s a small theoretical risk with herpes and HPV if fabric touches an active lesion and is worn immediately after.
If you’re reading this because you shared underwear and you’re now worried, take a breath. The risk is low for the vast majority of STIs. Here’s what the evidence actually says.
Worried? Get tested with a discreet home STI test kit
Which STIs Can Survive on Fabric?
STI-causing organisms vary hugely in how long they survive outside the body. Most die within seconds to minutes on dry surfaces. A few are hardier.
| STI | Survives on Fabric? | Risk from Shared Underwear | How It’s Actually Transmitted |
|---|---|---|---|
| Chlamydia | No (dies almost immediately) | Essentially zero | Direct sexual contact (vaginal, anal, oral) |
| Gonorrhoea | No (very fragile outside the body) | Essentially zero | Direct sexual contact |
| HIV | No (cannot survive outside bodily fluids) | Zero | Blood, semen, vaginal fluid, breast milk |
| Syphilis | No | Essentially zero | Direct contact with a syphilis sore |
| Herpes (HSV) | Briefly (minutes on moist fabric) | Very low, theoretical | Skin-to-skin contact with active sore |
| HPV | Possibly (more resilient) | Very low, theoretical | Skin-to-skin genital contact |
| Trichomoniasis | Briefly on moist surfaces | Very low | Sexual contact, rarely moist shared items |
| Pubic lice (crabs) | Yes (up to 48 hours) | Possible | Close body contact, shared bedding/clothing |
| Scabies | Yes (up to 72 hours) | Possible | Prolonged skin contact, shared bedding/clothing |
Chlamydia and Underwear
Chlamydia trachomatis bacteria are extremely fragile outside the human body. They require the warm, moist conditions of human mucous membranes (genitals, throat, rectum) to survive. On dry fabric like underwear, the bacteria die almost instantly.
NHS guidance is clear: chlamydia is spread through vaginal, anal, or oral sex, or by sharing sex toys. It is not spread through casual contact, sharing clothing, or using the same toilet. You cannot get chlamydia from someone’s underwear.
Read more: What is chlamydia?
Herpes and Underwear
Herpes simplex virus (HSV) can survive briefly on moist surfaces, but the viral load on fabric would be extremely low. For transmission to occur, the virus would need to transfer from a fresh, active herpes lesion onto fabric and then make contact with your mucous membranes or broken skin almost immediately.
In practice, this is extraordinarily unlikely. Herpes is transmitted through direct skin-to-skin contact with an active sore or through viral shedding (when the virus is active on the skin surface without a visible sore). Wearing someone else’s underwear is not a recognised transmission route in any NHS or BASHH guidance.
HPV and Genital Warts
HPV is more resilient than many other STI-causing organisms and can survive on surfaces for longer. There is limited evidence suggesting HPV DNA can be detected on underwear and other fomites (objects that can carry infection). However, detecting DNA is not the same as proving transmission.
The overwhelming majority of HPV transmission occurs through direct genital skin-to-skin contact during sex. While a theoretical risk from shared underwear exists, it has never been documented as a confirmed transmission route in clinical literature.
Pubic Lice and Scabies: The Real Risk
If there’s one thing you should genuinely be cautious about when sharing clothing or bedding, it’s pubic lice (crabs) and scabies. These are parasites, not bacteria or viruses, and they can survive on fabric for 24-72 hours.
Pubic lice can be transmitted through shared underwear, towels, and bedding. They’re tiny insects that live in coarse body hair and lay eggs (nits) on hair shafts. Symptoms include itching in the pubic area and visible lice or eggs.
Scabies mites can survive up to 72 hours on clothing and bedding. They burrow into the skin and cause intense itching, especially at night. Scabies spreads primarily through prolonged skin contact but can spread through shared fabrics in some cases.
Both are treatable with over-the-counter or prescription treatments. Read more: What are pubic lice? | What are scabies?
When Should You Actually Worry?
You should consider getting tested if:
- You’ve had unprotected sexual contact (vaginal, anal, or oral) with someone whose STI status you don’t know
- A sexual partner has told you they have an STI
- You have symptoms: unusual discharge, pain when urinating, sores, itching, or rashes in the genital area
- You found pubic lice or noticed intense itching after sharing bedding or clothing with someone who has lice or scabies
Simply sharing underwear with a friend, family member, or flatmate (while not ideal hygiene) is not a reason to panic about STIs. The risk from fabric contact alone is negligible for chlamydia, gonorrhoea, HIV, and syphilis.
How to Reduce Any Risk
- Don’t share underwear. This is basic hygiene advice, not STI-specific
- Wash shared clothing and bedding at 60°C or above to kill any potential parasites
- If you share towels or swimwear, wash them between uses
- Get tested regularly if you’re sexually active, especially with new partners
- Use condoms and dental dams during sex for genuine STI protection
When to Get Tested
If you’re anxious after sharing clothing or underwear, getting tested will give you peace of mind. Most STI tests are quick, painless, and can be done at home.
Order a discreet home test kit or visit your nearest sexual health clinic. Results are usually available within 2-3 days.
Frequently Asked Questions
Can you get chlamydia from trying on swimwear in a shop?
No. Chlamydia bacteria cannot survive on dry fabric. Trying on swimwear in a changing room poses no risk of chlamydia transmission. Shops typically require you to keep your own underwear on when trying swimwear, which is a general hygiene measure, not an STI precaution.
Can you catch an STI from a toilet seat?
No. STI-causing organisms cannot survive long enough on hard, dry surfaces like toilet seats to infect someone. This is a persistent myth with no evidence behind it. Read more: Can you catch an STI from a toilet?
Can sharing a towel give you an STI?
For most STIs, no. Pubic lice and scabies can potentially be transmitted through shared towels, but chlamydia, gonorrhoea, HIV, herpes, and syphilis cannot realistically spread this way.
Itching after wearing someone else’s underwear is more likely caused by a reaction to their laundry detergent, fabric softener, or general skin irritation than an STI. If the itching persists for more than a few days, or if you notice small insects or eggs in your pubic hair, see your GP or pharmacist. It could be pubic lice.
Can you get HIV from blood on clothing?
HIV cannot survive outside the body for more than a few minutes in most conditions. Even if there were blood on clothing, the virus would be inactive by the time you encountered it. HIV is transmitted through direct contact with infected blood, semen, vaginal fluid, or breast milk during sex, needle sharing, or from mother to child. Clothing is not a transmission route.
Related reading
- Blood Test for Syphilis, Hepatitis B and Hepatitis C
- Can You Get an STI From Being Fingered?
- Can You Catch an STI From a Toilet Seat?
- Can You Clear HPV Once You Have It?
- Can You Die From Hepatitis B?
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.
