6 ways to catch an STI without having sex

Many people assume that sexually transmitted infections (STIs), also known as sexually transmitted diseases (STDs), can only be transmitted through sexual intercourse. However, having unprotected sex, like vaginal sex, anal sex, or oral sex without a condom, isn’t the only way to get an infection. In some cases, you don’t need to have penetrative sex at all.

But how does this happen? If you’re sexually active, keep reading to find out more.

It’s always better to know your sexual health status.

1. Contaminated food and drinks

When we think about STIs, food and drink rarely come to mind. That’s because most STIs require direct contact with bodily fluids or mucous membranes to spread. However, there’s one notable exception: Hepatitis A.

Unlike infections like Chlamydia or Gonorrhoea, which can’t survive outside the body for long, Hepatitis A is a resilient virus that can be transmitted through contaminated food or water.

Hepatitis A is primarily transmitted via the oral faecal route, meaning the virus spreads when microscopic traces of faecal matter from an infected person contaminate food or water and are then ingested by another person. This usually happens when microscopic traces of faecal matter enter the food chain—often due to poor hygiene during food preparation or unsanitary water sources.

2. Through a contaminated blood transfusion

Blood transfusions are life-saving procedures, but they can carry a small risk of transmitting blood borne infections if the donated blood is contaminated.

While modern screening procedures have made this risk extremely low in many countries, it’s still possible under certain circumstances. STIs like HIV, Hepatitis B, Hepatitis C, and Syphilis are bloodborne pathogens, meaning they can survive and spread through blood-to-blood contact. If infected blood enters your bloodstream during a transfusion, an infection can establish itself.

Today, donated blood is rigorously tested using nucleic acid testing (NAT), which detects viral genetic material early, reducing the risk to less than one in a million donations in high-income countries.

However, risks remain in regions with limited resources or during emergencies where screening protocols may not be fully implemented. Proper sterilisation of medical equipment is also essential to prevent the spread of blood-borne infections during transfusions and other medical procedures.

3. Sharing dirty sheets, towels, or clothes

It’s a common worry: could you catch an STI sleeping in someone else’s bed or borrowing their clothes?

The short answer is that most STIs can’t survive outside the human body for long, making transmission through fabrics extremely unlikely. The viruses and bacteria that cause STIs require direct contact with bodily fluids or mucous membranes to spread. Dry textiles don’t provide the environment these pathogens need to survive.

However, there are exceptions. Certain parasitic infections and skin-related conditions can persist on fabrics for a short time. Pubic lice (crabs) and Scabies mites can live on bedding, towels, or clothing for up to 24–48 hours, and molluscum contagiosum, a viral skin infection, can also spread through contaminated items and surfaces.

These infections aren’t technically STIs in the traditional sense, but they’re often associated with sexual contact and can be transmitted indirectly through shared linens or garments.

4. Sharing used razors

Sharing a razor might seem harmless, but it can carry a hidden health risk. While most STIs are spread through sexual contact, some can also be transmitted through blood exposure. Razors often cause tiny cuts and nicks in the skin. If someone with a bloodborne infection uses that razor, and you then use it on broken skin, there is a potential route for transmission.

The risk is considered low in everyday use because many STI-causing pathogens don’t survive long outside the body. However, viruses like Hepatitis B and Hepatitis C can remain infectious on surfaces for days. This means that sharing razors is not recommended, especially if you or someone else has cuts or sores.

Beyond bloodborne viruses, some skin-related infections can also spread via razors. For example, molluscum contagiosum and certain strains of HPV (which cause Genital Warts) can transfer if a razor comes into contact with infected skin lesions. While these are not the most common transmission routes, they highlight why personal grooming items should never be shared.

5. Foreplay and skin to skin contact

Foreplay often involves intimate physical contact, which means some STIs can be passed on even without penetrative sex.

Activities like kissing, oral contact, oral genital contact, and skin to skin contact can transmit infections like Herpes Simplex Virus (HSV), HPV, and Syphilis, all of which don’t require intercourse to spread.

Anal secretions, vaginal fluids, and vaginal secretions can all carry infectious agents. Open sores or cuts in the genital area can also increase the risk of infection.

6. Sharing unwashed sex toys

Sharing sex toys without proper cleaning can significantly increase the risk of transmitting STIs. This is because many STIs are spread through contact with bodily fluids or mucous membranes, and sex toys can retain traces of these fluids after use. If one person uses a toy and then another without thorough cleaning or a fresh condom, bacterial infections such as Chlamydia and Gonorrhoea, as well as Trichomonas, can easily be transmitted.

Viruses like HIV, Hepatitis B, and Hepatitis C can also pose a risk from unwashed sex toys. Additionally, infections such as Genital Herpes, Oral Herpes, and HPV can spread through shared toys, even if there are no visible sores. This makes cleaning and barrier protection essential for reducing risk.

To stay safe, always put a new condom on the toy for each partner and clean toys thoroughly with soap and warm water after every use. Regular testing is important for anyone who is sexually active or shares sex toys, as it helps detect infections early and prevent further spread.

Protect your sexual health

If you’re worried about any recent sexual activity, you should get tested. Warning signs like noticeable symptoms, unusual discharge, painful sex, flu like symptoms, or severe pain are all reasons to seek testing. People with an active sex life and multiple partners should be especially vigilant.

Better2Know can help you book a test or screen at a sexual health clinic near you. Call our team of dedicated Sexual Health Advisors for more information.

Help protect your health and the health of your sexual partners.