How to reduce your risk of catching and passing on an STI

No single method protects you completely, so the best approach combines a few:

• use a condom or a dam every time you have sex
• get vaccinated against the STIs you can be protected from
• test regularly, and whenever you have a new partner
• ask about PrEP if you’re at higher risk of HIV

Masturbating on your own is the only sex with no risk of an STI, as long as you don’t share sex toys.

Condoms, vaccines and regular testing together give you the best protection.

The NHS says using a condom every time you have sex is the best way to protect you and your partner from HIV and other STIs. Used correctly, condoms are also up to 98% effective at preventing pregnancy.

Condoms protect less well against infections spread by skin contact outside the area they cover:

• Herpes and genital warts can pass on if the condom doesn’t cover the infected skin
• Syphilis can pass on through contact with a sore
• condoms don’t protect against pubic lice at all

Don’t use oil-based products, such as Vaseline, massage oil or hand cream, with latex condoms, as they can make them break. Water-based or silicone-based lube is fine.

A condom every time still protects you from most STIs. Read more in “Can you still get an STI if you wear a condom?”

Oral sex can pass on STIs such as Herpes, Gonorrhoea and Syphilis. For oral sex on a penis, use a condom. For oral sex on a vulva or anus, use a dental dam: a thin square of latex or plastic that you place over the vulva or anus.

Use a new dam each time, and keep the same side against the skin. If you don’t have one, you can make one by cutting the tip and ring off a condom, then cutting it along its length. There’s little research on how well dams work, but UK guidance recommends them.

A dam goes over the vulva or anus, not over your mouth.

Touching and other sex without penetration carry a much lower risk, but they’re not risk-free:

• skin contact: Herpes, genital warts, Syphilis sores, mpox, pubic lice and scabies can all spread through close skin contact
• kissing: a cold sore can pass on Herpes, but you can’t get HIV or genital warts from kissing
• fingers: with fingering and fisting, the risk rises with any damage to the skin, and gloves can lower it
• sex toys: if you share them, wash them between uses and put a new condom on them each time

Infections can also pass on even if the penis doesn’t fully enter the vagina, or the man doesn’t ejaculate.

Less risky isn’t the same as no risk. Read more in “Can you get an STI from a sex toy?”

Anal sex has a higher risk of passing on STIs than many other types of sex, because the lining of the anus is thin and easily damaged. For HIV, the risk from a single act with a partner who has HIV and isn’t on treatment is about 1 in 90 for the receptive partner, compared with about 1 in 1,000 for receptive vaginal sex.

To make anal sex safer:

• use a condom, with plenty of water-based or silicone-based lube
• stop if it hurts
• use a new condom if you move from anal to vaginal sex
• remember that rimming (oral-anal sex) can pass on Hepatitis A and Shigella

With HIV, a partner whose treatment keeps the virus undetectable can’t pass it on. Read more in “Is unprotected anal sex dangerous?”

Vaccines can protect you from several STIs:

• HPV: offered to all children aged 12 to 13, and to men who have sex with men up to and including the age of 45. If you missed it, there’s a catch-up until your 25th birthday for girls, and for boys born after 1 September 2006
• Hepatitis A and B: recommended for men who have sex with men. Hepatitis B vaccination is also recommended for people who change partners often and for sex workers
• the MenB vaccine for Gonorrhoea: offered since August 2025 to men who have sex with men who are at higher risk. It gives around 30% to 40% protection
• mpox: recommended mainly for men who have sex with men who have multiple partners

If you’re eligible for a vaccine, it’s one of the simplest ways to protect yourself.

Medicines can also lower the risk of HIV and some other STIs:

• PrEP: medicine you take every day, or before and after sex, to prevent HIV. Taken daily, it’s around 99% effective, but it doesn’t protect against other STIs
• PEP: emergency medicine that can stop you getting HIV after a possible exposure. It must be started within 72 hours, and works best the sooner you take it
• U=U: someone with HIV whose treatment keeps the virus undetectable can’t pass HIV on through sex
• doxyPEP: since 2025, UK guidelines have recommended a dose of doxycycline after sex for gay, bisexual and other men who have sex with men, and trans women, at higher risk of Syphilis

If you think you’ve been exposed to HIV in the last 72 hours, get urgent medical care about PEP.

If you’re at higher risk of HIV, ask about PrEP.

Some things make catching an STI more likely:

• having more sexual partners, or partners whose STI status you don’t know
• drinking or taking drugs, which can make it harder to use condoms, and chemsex, using drugs to enhance sex
• having another STI, as Herpes, Gonorrhoea and Syphilis can raise the risk of HIV

None of these means you’ll catch an STI, but they’re good reasons to test more often.

Many STIs cause no symptoms, so testing is the only way to find them and stop them being passed on. UK guidance says:

• test once a year if you’re sexually active, and whenever you have a new partner
• test every 3 months if you’re at higher risk, for example if you take PrEP, have more than 10 partners a year or use drugs during sex
• test at the start of a new relationship, before you stop using condoms

After sex, you can test for Chlamydia and Gonorrhoea from 2 weeks. A lab HIV test is reliable from 45 days, and a Syphilis test can miss an infection in the first 3 months, so you may need a repeat test.

Regular testing protects your partners as well as you. Read more in “New relationship? Get tested together before you stop using condoms”

Better2Know offers:

• Full Screen: tests for 7 infections, including HIV, Syphilis, Hepatitis B, Chlamydia and Gonorrhoea, from 28 days after sex, with results in 3 days (5 days for the home test).
• Peace of Mind: tests for Chlamydia, Gonorrhoea and Syphilis from 14 days after sex, with results in 2 days. You can also order a home test kit.
• Confidence Screen: for gay and bisexual men, it adds throat and rectal swabs for Chlamydia and Gonorrhoea to the same 7 infections, from 28 days after sex, with results in 5 days. You can also order a home test kit.
• Blemish Screen: if you’ve noticed a lump, blister or sore in your genital area, it tests a swab from it for Herpes 1, Herpes 2, HPV and Syphilis, with results in 5 days.

You can book any of these at one of our clinics. If you test before 45 days, a negative HIV result needs a repeat test. A Syphilis test in the first 3 months after sex can miss the infection, so you may need a repeat test. Not sure which test you need? Our Patient Care Team is available 24/7 on 020 7099 0955.

Can you get an STI from kissing?

You can get Herpes from kissing someone with a cold sore. You can’t get HIV or genital warts from kissing.

When can I have sex again after treatment for an STI?

Don’t have sex, including oral sex, until you and your partners have finished treatment. For Gonorrhoea, wait until 7 days after you’ve both finished, and for Syphilis, 2 weeks.

Can we stop using condoms if we’ve both tested negative?

If you’ve both tested after the window periods and only have sex with each other, you may decide to. Until then, keep using condoms.

Every type of sex carries some risk of an STI, but you can lower it a lot. Use a condom or a dam every time, get the vaccines you’re eligible for, ask about PrEP if you’re at higher risk of HIV, and test regularly, especially with a new partner.

Book a Full Screen at a clinic near you or order a home test kit. Our Patient Care Team is available 24/7 on 020 7099 0955.

Not in the UK? Choose your country from the selector at the top of the page for local tests and prices.

This article originally appeared on 7 June 2012 and was last updated on 1 October 2026.

This article is general information and not a substitute for personal medical advice.

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