HIV in Canada: A primer for service providers

Post-exposure prophylaxis (PEP)

Key Points

  • Post-exposure prophylaxis (PEP) is the use of antiretroviral drugs after an exposure to HIV, to reduce the risk of HIV transmission.
  • PEP works by helping to prevent replication of the HIV virus once it has made its way into the body.
  • PEP can reduce the risk of HIV transmission by over 80% when used consistently and correctly.

Post-exposure prophylaxis (PEP) is the use of antiretroviral drugs after an actual or suspected exposure to HIV to reduce the risk of HIV transmission. It should be started as soon as possible after a real or suspected HIV exposure but definitely within 72 hours. A combination of  three antiretroviral drugs is generally prescribed for PEP use. These medications must be taken every day for four weeks.

PEP works in an HIV-negative person after HIV has made its way into the body. If this happens, the medications in PEP may prevent the virus from multiplying and spreading throughout the body.

Research has found that PEP can reduce the risk of HIV infection by over 80%. We know that people can sometimes become infected with HIV despite taking PEP, and that PEP is most likely to work when used consistently and correctly. Factors that can limit the effectiveness of PEP include: low adherence to the full four-week course of pills, later PEP initiation, and continued exposures to HIV while taking PEP (PEP is only meant to reduce the risk from a single exposure).

The potential risks of PEP include drug toxicity and side effects, interactions with other medications, and the development of drug-resistant strains of HIV (if infection occurs). A person who wants to use PEP will have their HIV risk assessed, because PEP is only meant to be used after a potential high-risk exposure. A person will also be tested for HIV to confirm that they are HIV negative.

Resources

Post-Exposure Prophylaxis for Prevention (PEP)

Post-exposure Prophylaxis (PEP) – CATIE fact sheet

Can we prevent infection with HIV after an exposure? The world of post-exposure prophylaxis (PEP)Prevention in Focus

The PEP Program at Clinique l’Actuel Programming Connection

Updated Guidelines for Antiretroviral Postexposure Prophylaxis After Sexual, Injection Drug Use, or Other Nonoccupational Exposure to HIV—United States, 2016 – U.S. Centers for Disease Control and Prevention (CDC)

 

Sources

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  2. Schechter M, do Lago RF, Mendelsohn AB, et al. Behavioral impact, acceptability, and HIV incidence among homosexual men with access to postexposure chemoprophylaxis for HIV. Journal of Acquired Immune Deficiency Syndromes. 2004 Apr 15;35(5):519–525.
  3. Barber TJ, Benn PD. Postexposure prophylaxis for HIV following sexual exposure. Current Opinion in HIV and AIDS. 2010 Jul;5(4):322–326.
  4. Poynten IM, Jin F, Mao L, et al. Nonoccupational postexposure prophylaxis, subsequent risk behaviour and HIV incidence in a cohort of Australian homosexual men. AIDS London England. 2009 Jun 1;23(9):1119–1126.
  5. Heuker J, Sonder GJB, Stolte I, et al. High HIV incidence among MSM prescribed postexposure prophylaxis, 2000-2009: indications for ongoing sexual risk behaviour. AIDS London England. 2012 Feb 20;26(4):505–512.
  6. Roland ME, Neilands TB, Krone MR, et al. A randomized noninferiority trial of standard versus enhanced risk reduction and adherence counseling for individuals receiving post-exposure prophylaxis following sexual exposures to HIV. Clinical Infectious Diseases. 2011 Jul;53(1):76–83.
  7. Dodds C, Hammond G, Keogh P, et al. PEP talk: awareness of, and access to post-exposure prophylaxis among gay & bisexual men in the UK. London: Sigma Research; 2006 Nov. Available from: www.sigmaresearch.org.uk/downloads/report06d.pdf