What is HIV PrEP?

HIV transmission elimination
Public Health Scotland
  • PrEP stands for ‘pre-exposure prophylaxis’.​
  • PrEP is an oral medication* taken before and after potential exposure to HIV to reduce the risk of the virus establishing itself in the body.​
  • PrEP is an effective HIV prevention intervention reducing the chance of sexual acquisition of HIV by up to 99%4.​
  • PrEP is used to prevent HIV acquisition in people who have tested negative.​
  • PrEP forms one component of wider HIV prevention for those at risk of HIV acquisition in Scotland1.
  • HIV transmission occurs over a short time. After sexual exposure, it takes about 30 minutes for the virus to enter the circulation.​
  • It then takes 2-3 days for the infection to become established in the body.​
  • For HIV PrEP to be most effective the medicine needs to be at protective levels throughout this period.​
  • HIV PrEP needs to be taken before and after sex.
  • Medication currently recommended for HIV PrEP interventions is a single, fixed dose, oral combination tablet.​
  • In the vast majority of cases, this comprises of two antiretroviral drugs, tenofovir disoproxil and emtricitabine. ​
  • An alternative combination with tenofovir alafenamide and emtricitabine (Descovy) can be used if there are renal/bone contraindications or complications from tenofovir disoproxil. This is also recommended for initiation under age 18 years due to bone mineral density risks. The latter is only provided in specialist sexual health services following MDT discussion. 

*Injectable Cabotegravir PrEP is now available for restricted indications via specialist services only9

National intervention programme​

  • HIV PrEP is part of a wider national prevention programme delivered by the NHS via specialist sexual health services.​
  • PrEP does not prevent against other STIs, therefore, condom use is still important.​
  • Regular testing for HIV and other STIs is recommended as part of routine care.​

Additional strategies include:​

  • Regular HIV testing ​
  • Treatment for people living with HIV to achieve U=U*​
  • PEPSE**​
  • Condoms​
  • Injecting equipment provision​
  • Behaviour change interventions​

 

*U=U, undetectable = untransmittable, BHIVA has endorsed recent research which shows that if a person living with HIV is on effective treatment and undetectable (<200 copies of virus/ml of blood) for longer than 6 months they cannot transmit the virus.​

**Post exposure prophylaxis after sexual exposure to HIV