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 2001Sultan 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 NICE NG221. The regimen typically involves a 28-day course of antiretroviral therapy, started as soon as possible but no later than 72 hours post-exposure NICE NG221.
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 NICE NG221. Follow-up HIV testing is recommended at 4 to 6 weeks and again at 3 months post-exposure to confirm seronegativity NICE NG221.
Supportive counselling and education about adherence, side effects, and risk reduction strategies are integral to PEP provision NICE NG221. 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 NICE NG221. This approach aligns with international literature emphasizing early initiation and comprehensive care Fong 2001Sultan et al. 2014.
Key References
- NG221 - Reducing sexually transmitted infections
- NG60 - HIV testing: increasing uptake among people who may have undiagnosed HIV
- (Fong, 2001): Post-exposure prophylaxis for HIV infection after sexual assault: when is it indicated?
- (Sultan et al., 2014): Current perspectives in HIV post-exposure prophylaxis.
- (Bachmann et al., 2024): CDC Clinical Guidelines on the Use of Doxycycline Postexposure Prophylaxis for Bacterial Sexually Transmitted Infection Prevention, United States, 2024.