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.
Most STIs are transmitted through sexual contact, but a small number can also spread through non-sexual routes — mother to baby during birth, contact with infected blood, or occasionally close non-sexual contact. Understanding these exceptions helps put both risks and myths in perspective.
Here’s what can realistically spread outside sex.
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Infections That Can Spread Non-Sexually
| Infection | Non-Sexual Routes |
|---|---|
| HIV | Mother to baby (pregnancy, birth, breastfeeding); sharing injecting equipment; needlestick injuries; blood transfusions (screened out in UK) |
| Hepatitis B | Mother to baby; sharing injecting equipment; household contact in some settings |
| Hepatitis C | Sharing injecting equipment (main route); occupational exposure; rarely shared personal items like razors |
| Herpes (HSV-1) | Kissing; sharing drinks, utensils, toothbrushes; from mother to baby during birth |
| HPV | Childhood skin-to-skin contact can spread non-genital types; rarely mother to baby |
| Pubic lice | Rarely from shared bedding or towels |
| Scabies | Close non-sexual skin contact; shared bedding |
| Mpox | Close physical contact, household contact; currently most cases are linked to sexual networks |
Mother-to-Baby Transmission
Several STIs can pass from mother to baby:
- HIV — risk very low with treatment
- Hepatitis B — prevented with vaccination at birth
- Syphilis — can cause serious congenital infection; antenatal screening identifies this
- Herpes — rarely during birth, mainly if mother has an active outbreak
- Gonorrhoea and chlamydia — can cause eye infection in newborns
UK antenatal care includes routine screening for these infections to protect babies.
Injecting Drug Use
Sharing needles, syringes, spoons and other injecting equipment can transmit:
- HIV
- Hepatitis B
- Hepatitis C
- Less commonly other bloodborne infections
Needle and syringe programmes provide clean equipment to reduce harm.
Casual Contact and Childhood Exposure
Some infections commonly treated as STIs are often acquired outside sex:
- HSV-1 — most children catch it through kissing and shared drinks before they are sexually active
- Common warts — HPV types that cause hand warts are acquired through casual contact
- Hepatitis B in some countries — can spread through household contact in high-prevalence areas
What DOES NOT Spread Non-Sexually
- HIV — not through kissing, casual contact, swimming pools, mosquitoes, or toilet seats
- Chlamydia and gonorrhoea — not through casual contact or shared surfaces
- Syphilis (in adults) — needs direct contact with an infectious lesion
- Trichomoniasis — sexual contact is the main route
Protecting Yourself
- Use clean injecting equipment
- Get vaccinated (HPV, hepatitis A and B)
- Use precautions during pregnancy to protect your baby
- Don’t share personal items like razors, toothbrushes or nail clippers with others
- Wash hands and cover wounds in healthcare settings
Read more: How you can’t get HIV | Hepatitis B and C | What is HIV?
Frequently Asked Questions
Can I get an STI from sharing a razor?
Theoretically possible for blood-borne infections like hepatitis C if there’s fresh blood. In practice, the risk is very low.
Can babies catch STIs from their mothers?
Yes — several infections can be transmitted during pregnancy or birth. Antenatal screening and treatment reduce these risks significantly.
Is casual contact ever an STI risk?
For the main STIs (chlamydia, gonorrhoea, HIV, syphilis), no. Casual contact is safe.
Related reading
- A to Z of Sex: Sexual Health Terms Explained
- Alcohol and HIV: What You Need to Know
- Anxiety and HIV: Coping and Getting Support
- Are All STIs Curable?
- Blood Problems and HIV: Anaemia, Low Platelets and More
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.
