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Safer sex: How to prevent STIs

02 May 2019 in Health


Everyday more than one million sexually transmitted infections (STIs) are acquired around the world. STIs can have mild symptoms, and some have no symptoms at all. That’s why the prevention and control of sexually transmitted infections is so important.

If you’re having vaginal, anal, or oral sex you are at risk of catching an STI, but by having ‘safer sex’ you can greatly reduce this risk.

Safer sex means reducing your risk of contracting an STI when you have sex. This can be done a few different ways, including:

  • Regular sexual health check-ups
  • Getting vaccinated against STIs
  • Using barrier protection (such as condoms)
  • Being mutually sexually exclusive (both you and your partner agree to only have sex with each other)

Here we will outline which STIs you are at risk of catching when you have different types of sex, and how you can reduce this risk with safer sex practices.

How to have safer sex and prevent STIs

Different types of sexual activities can put you at risk for different STIs.

STIs are not just transferred through semen, they can also be transferred through vaginal fluids, skin contact, blood, saliva, and faeces.

There are many ways to reduce the risk of picking up an STI, but the only way to remove the risk entirely is by abstaining from any sexual activity which involves the exchange of body fluids. This means no direct oral, genital, or anal contact.

STDs (sexually transmitted diseases) and STIs both refer to a sexually transmitted infection. The two terms are often used interchangeably, but there is a distinction between the two.

If you have an STI it means you have an infection, but it has not developed into a disease. For example, if someone has been infected with HPV, they may not have any symptoms but they carry the virus, so they have an STI. However, if that person develops cervical cancer from HPV they now have an STD.

If you want to have sex and reduce the risk of getting STIs then safer sex is the best alternative. Here you will find a general guideline of the STIs you are at risk of when you perform different types of sexual activity, and how to protect against them.

Vaginal penetrative sex

Vaginal penetrative sex puts you at risk for the following STIs:

Safer sex practices when having vaginal penetrative sex include using a condom, which can reduce the risk of contracting or passing on an STI.

Anal penetrative sex

Anal penetrative sex can expose you to the following STIs:

  • Chlamydia
  • Genital herpes
  • Genital warts
  • Gonorrhoea
  • HIV
  • Syphilis

Use a condom during anal sex to reduce the risk of contracting or passing on an STI.

Oral sex

The STIs you’re at risk for when you have oral sex include:

  • Chlamydia
  • Herpes – type 1 and type 2, which can cause cold sores around the mouth and on the genitals or anus
  • Genital warts
  • Gonorrhoea
  • Hepatitis A, hepatitis B and hepatitis C
  • HIV
  • Syphilis

Use a condom during oral sex to lower the risk of contracting or passing on an STI.


It’s not common to contract an STI from fingering, but there is an increased risk if you have any cuts or wounds on your hands or fingers (no matter how small).

Sex toys

When using sex toys you can still contract the following STIs:

  • Chlamydia
  • Syphilis
  • Herpes

If there are any cuts or sores around the vagina, anus, or penis, and there’s blood, there is also an increased risk of:

  • Hepatitis B
  • Hepatitis C
  • HIV

To reduce the risk of STIs when using sex toys make sure to keep them clean and use condoms with them.

Urine and faeces

If the person being urinated on has broken skin there is a risk of infection.

Poo creates a greater risk of infection. Infections such as shigella (a bacterial intestinal infection) can be caught during oral-anal sex. Giving oral sex after anal sex also carries risks because a small amount of infected poo can get into the mouth and cause infection.

Poo can spread HIV if there is HIV-infected blood in the poo.

Poo can contain hepatitis A, which can cause infection if it comes into contact with broken skin, the mouth, or the eyes.


If the skin is cut (even without sexual contact) then HIV, hepatitis B and hepatitis C can be transmitted.

If you perform cutting as part of your sexual activities there are ways to protect yourself from STIs. To reduce the risk of infection, sterilise cutting and piercing equipment and do not share it.

Getting tested regularly

If you are sexually active you should get checked for STIs. How frequently you get tested will depend on how often you have sex and how many partners you have. General guidelines for when to get tested are as follows

  • Get tested at least every six months if you have casual sex with different partners
  • Get tested at least every three months if you have multiple sexual partners
  • Get tested before you have sex at the start of a new relationship
  • Visit an STI clinic immediately if you have any symptoms of an STI, and don’t have sex until you’re given the all clear

Getting vaccinated

There are vaccines available for HPV, hepatitis A, and hepatitis B.

As well as vaccines there are other interventions which can reduce your risk of contracting an STI. For example, male circumcision can reduce the risk of HIV by around 60% in men who have heterosexual sex, and it can provide some protection against herpes and HPV.

Tenofovir gel has also been found to provide some protection from HSV-2 (a type of herpes virus) when used as a vaginal microbicide.

If you know your partner is HIV positive, or you are at an increased risk of being exposed to HIV, it may be beneficial for you to see a doctor and take PrEP. PrEP is a drug which reduces the chances of the HIV virus multiplying in your body.

Daily PrEP reduces the risk of getting HIV from sex by more than 90%. Your risk of getting HIV from sex can be even lower if you combine PrEP with condoms and other prevention methods.


The only way to be 100% risk free of STIs is to avoid any intimate contact where body fluids are exchanged, which means no direct oral, genital, or anal contact.

Everyone should be free to enjoy a healthy sex life. Use protection when you engage in sexual activity, and remember to get tested.

If you live in the US and want to get tested for STIs at home, try myLABBOX.


Tht.org.uk. A healthy sex life | Terrence Higgins Trust. 2019. Cited 7 May 2019.

Acog.org. Addressing Health Risks of Noncoital Sexual Activity. 2019. Cited 7 May 2019.

Ashasexualhealth.org. Vaccines | American Sexual Health Association. Cited 7 May 2019.

Helloclue.com. Clue: Period and Ovulation Tracker for iPhone and Android. 2019. Cited 7 May 2019.

Cdc.gov. PrEP | HIV Basics | HIV/AIDS | CDC. 2019. Cited 7 May 2019.

Nhs.uk. Sex activities and risk. 2019. Cited 7 May 2019.

Who.int. Sexually transmitted infections (STIs). (2019). Cited 7 May 2019.

Nhs.uk. Vaccination. 2019. Cited 7 May 2019.

Important: Our website provides useful information but is not a substitute for medical advice. You should always seek the advice of your doctor when making decisions about your health.

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