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  • Cassidy Ferrari

I keep hearing the word PEP - What is it?

Updated: Mar 2, 2023

The post-exposure HIV drug it’s worth knowing about.

The rising awareness and use of PrEP has revolutionised sexual health by reducing HIV infections, and we’d encourage anyone who may benefit from this treatment to consider finding out more about it. The reality is that we don’t always have barrier-protected sex, sexual encounters can be spontaneous. This is where PEP comes in - a ‘post-exposure’ treatment that can be used when a specific encounter is deemed high-risk for HIV transmission.

It’s important to know that you can do something if you find yourself in a situation with concerns you may have been exposed to the HIV virus. The data suggests that there is relatively low uptake of PEP in the LGBTQI community in areas outside of London, so knowing what it is and when it can be used is vital and worth sharing.

What is PEP?

PEP or PEPSE stands for Post-exposure Prophylaxis (after Sexual Exposure). It’s a course of medication that can be taken within 72 hours of potential exposure to HIV through sexual activity or contaminated equipment. Despite it not being 100% effective at preventing the transmission of HIV, it significantly reduces the chance of it. The Terrence Higgins Trust suggests that it should be considered as an ‘emergency measure to be used as a last resort’.

Once it has been prescribed, the treatment involves taking two tablets, Truvada and Raltegravir, which must be taken daily for the 28 day course - not doing so will impact how well it works.

Who is PEP for?

PEP is provided for free by the NHS to people of all gender identities and sexual orientation who are HIV-negative. Not all incidents of exposure will meet the criteria for prescription. A discussion with a healthcare professional at an appropriate clinic will help you determine this.

Risk of infection is considered highest after unprotected penetrative sex with someone who is both HIV positive and has a detectable or unknown viral load - a term which describes how much HIV is detectable within a person’s bloodstream. PEP can be prescribed to anyone who has been in this situation in the past 72 hours. However, healthcare professionals are aware that we are not always in possession of this information, and that not all exposure is consensual - always ask if you’re not sure what to do.

The NHS considers risk factors such as the type of sexual activity and the HIV rates in the other person’s country of origin in its decision making.

If a sexual partner has been receiving HIV treatment for at least six months and has an undetectable viral load, PEP is rarely prescribed as transmission is very unlikely.

Where can you get PEP?

The best place to access PEP is your local sexual health clinic. If you tell them what the appointment is for, they’ll prioritise seeing you to assess your eligibility. Be prepared to answer some questions about your sexual health at the appointment, this is about appropriate information gathering. A blood test will be taken to confirm HIV-negative status, and they will often offer tests for other STIs too.

If you need PEP when a clinic is closed, assessment and prescription can also be provided by A&E departments at many hospitals. It’s always better to call A&E than wait until the clinic re-opens, so you can get treatment as soon as possible. If you're unsure whether PEP is right for your situation, both your sexual health clinic and local A&E can provide guidance and support.

If you’d like to find out more about PEP or PrEP and where to access it, head to:

Terrence Higgins Trust -

NHS 111 for services near you - Local sexual Health Services

Photo Credit:

Jeffrey Beall, CC BY-SA 3.0 <>, via Wikimedia Commons



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