What are the current guidelines for initiating HIV Post-Exposure Prophylaxis (PEP) after potential sexual exposure?

Initiation of HIV post-exposure prophylaxis (PEP) following potential sexual exposure should be considered as an urgent intervention ideally started within 72 hours of exposure to maximise effectiveness. The decision to initiate PEP depends on the nature of the exposure, the HIV status of the source (if known), and the risk level of the exposure event.

PEP is recommended for individuals who have had a significant risk exposure, such as condomless vaginal, anal, or oral sex with a partner known to be HIV positive or of unknown status but at high risk of HIV infection. This includes sexual assault cases where the source is known or suspected to be HIV positive (Fong, 2001; Sultan et al., 2014).

UK guidelines emphasise rapid assessment and offer of PEP in sexual health services or emergency settings, with clear referral pathways to ensure timely access to treatment ¹. The regimen typically involves a 28-day course of antiretroviral therapy, started as soon as possible but no later than 72 hours post-exposure ¹.

Before initiating PEP, baseline HIV testing should be performed to exclude existing infection, alongside screening for other sexually transmitted infections and assessment of renal function due to potential drug toxicity ¹. Follow-up HIV testing is recommended at 4 to 6 weeks and again at 3 months post-exposure to confirm seronegativity ¹.

Supportive counselling and education about adherence, side effects, and risk reduction strategies are integral to PEP provision ¹. While UK guidelines do not routinely recommend PEP beyond 72 hours post-exposure, some literature discusses the potential for benefit in exceptional cases, though evidence is limited and such use should be carefully considered (Sultan et al., 2014).

In summary, current UK guidelines recommend initiating HIV PEP urgently within 72 hours after potential sexual exposure involving a high-risk source or event, with appropriate baseline and follow-up testing, adherence support, and referral to specialist sexual health services ¹. This approach aligns with international literature emphasizing early initiation and comprehensive care (Fong, 2001; Sultan et al., 2014).