Synopsis
Build an individual prevention plan combining consent, barriers, testing, HIV prophylaxis, contraception and current risk-based vaccination while explaining residual risk, programme eligibility and urgent post-exposure actions.
- Agree the patient’s priorities and describe practices, sites, timing, barriers, partners, pregnancy potential, consent and previous tests before choosing interventions.
- Condoms reduce many STI and pregnancy risks when used correctly throughout exposure, but protection varies by infection, anatomical site and uncovered skin.
- PrEP prevents HIV when taken correctly; it does not prevent pregnancy, syphilis, gonorrhoea, chlamydia, hepatitis C or infections spread from uncovered skin. The UK 4CMenB gonorrhoea programme continues, but use against gonorrhoea is off-label and individual protection is uncertain and likely low; the 2026 GoGoVax RCT found no evidence of protection in its high-risk study population, so continue condoms and testing.
Key red flags
A potentially substantial HIV exposure within 72 hours requires immediate specialist PEP assessment because benefit depends on starting promptly.
Possible pregnancy after recent unprotected sex requires time-sensitive emergency-contraception counselling and a later pregnancy-testing plan.
Sexual contact with acute hepatitis B may require vaccine and, within the relevant short interval, hepatitis B immunoglobulin under current Green Book guidance.
Fever, rash, severe pelvic or testicular pain, genital ulceration, neurological or ocular symptoms needs diagnostic assessment rather than prevention counselling alone.
Coercion, assault, intoxication that impaired consent, stalking or fear of a partner requires immediate safety and safeguarding action.
HIV, pregnancy and hepatitis B exposures can require prophylaxis or emergency contraception before routine results return.
A partner controlling barrier use, contraception, medicines or appointments may make a standard plan unsafe or impossible.
Investigation priorities
Match barriers, testing, PrEP or PEP, contraception and vaccines to actual practices and goals.
Management branches
An adult has new partners, sometimes uses condoms and wants to reduce HIV, STI and pregnancy risk.
- Ask about sites, timing, barriers, pregnancy potential, consent, previous tests, HIV prevention, vaccines and the patient’s main goal.
- Agree correct barrier use and supplies, site-specific testing and contraception, then assess PrEP eligibility and vaccination gaps.