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Post-exposure HIV prophylaxis

Last reviewed: 10 Nov 2023
Last updated: 01 Aug 2023



History and exam

Key diagnostic factors

  • exposure to HIV within past 72 hours
  • breakage, slippage, or nonusage of a condom
  • history of ejaculation from source
  • trauma or skin break
  • genital ulcers
  • source from high-risk group for HIV viremia
  • source from geographic area with high HIV prevalence
  • high-risk sexual history in exposed person
  • detectable HIV viral load in source
More key diagnostic factors

Other diagnostic factors

  • history of negative HIV test in source
  • source with hepatitis coinfection
  • antiviral HIV resistance in source
  • current prescription or nonprescription medications
  • history of drug allergies
  • flu-like illness
Other diagnostic factors

Risk factors

  • blood transfusion from HIV-positive donor
  • sharing injecting equipment
  • needlestick injury
  • receptive anal intercourse
  • receptive vaginal intercourse
  • mucus membrane exposure
  • insertive anal intercourse
  • insertive vaginal intercourse
  • receptive oral sex (fellatio)
More risk factors

Diagnostic investigations

1st investigations to order

  • HIV antigen/antibody blood test (blood ELISA or EIA)
  • rapid HIV point of care test (POCT)
  • renal function tests
  • liver function tests (LFTs)
  • hepatitis B serology
  • hepatitis C antibody
  • syphilis serology
  • pregnancy test
  • screening for other STIs
More 1st investigations to order

Investigations to consider

  • HIV viral load if symptoms of HIV seroconversion
More investigations to consider

Treatment algorithm


adults or adolescents ≥13 years: nonpregnant

pregnant or breastfeeding




Ming Jie Lee, BSc(Hons), MBBS, MRCP

Clinical Research Fellow

Department of Infectious Disease

Imperial College London




MJL has received consulting fees from Thriva Ltd. and conference reimbursement from Gilead Sciences, Inc., and travel grants from ViiV Healthcare, not related to this work.

Julie Fox, BSc(Hons), MBChB, MRCP, MD

HIV consultant and Honorary Senior Lecturer KCL

Department of HIV

Harrison Wing

Guy’s and St Thomas Hospital NHS Foundation Trust




JF declares that she has no competing interests.


Dr Ming Jie Lee and Dr Julie Fox would like to gratefully acknowledge Dr Jennifer A. Johnson, Dr Paul Sax, Dr Rebecca Plank, Dr Michael Brady, Dr Emily Cheserem, and Dr Claire M. Naftalin, the previous contributors to this topic.


JAJ declares that she has no competing interests. PS serves as a consultant for Abbott, BMS, Gilead, GSK, Merck, and Janssen. He receives grant support from BMS, Gilead, and GSK. EC has been sponsored by GlaxoSmithKline for several conferences and sponsored by Gilead Sciences, Bristol-Myers Squibb Pharmaceuticals, and Abbott Laboratories to attend various educational programs. CMN has been sponsored by Bristol-Myers Squibb Pharmaceuticals to attend an educational program. CMN is an author of a reference cited in this topic. MB not disclosed. RP declares that she has no competing interests.

Peer reviewers

Professor Margaret Johnson, MB BS, MD, FRCP

Clinical Director

HIV/AIDS Services

Royal Free Hampstead NHS Trust




MJ declares that she has no competing interests.

William Rodriguez, MD

Chief Medical Officer

Foundation for Innovative New Diagnostics (FIND)

Campus Biotech




Not disclosed.

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