HIV Prevention: PrEP & PEP

Pre- and post-exposure antiretroviral prophylaxis. See also HIV.

Pre-exposure prophylaxis (PrEP)

Antiretroviral prophylaxis taken by HIV-negative people at ongoing risk.

• Daily oral PrEP — tenofovir disoproxil/emtricitabine (originally Truvada; now cheaper generics). Reduces HIV acquisition by ~86–99% with good adherence.
• PBS-listed since April 2018 for HIV-negative people at medium-to-high risk; any doctor or nurse practitioner can prescribe it.
• On-demand (“2-1-1”) PrEP — for infrequent, planned condomless anal intercourse (typically with sexual-health-physician involvement); not recommended for people with hepatitis B or for vaginal exposure.
• Monitoring — confirm HIV-negative before starting; then HIV, renal function and STI screening around every 3 months.
• Long-acting injectable PrEP with cabotegravir (Apretude) is now PBS-listed — two monthly loading doses then an injection every 2 months — currently restricted to patients for whom oral PrEP is contraindicated/unsuitable.

Post-exposure prophylaxis (PEP)

Emergency antiretroviral treatment after a recent potential HIV exposure, to reduce the risk of transmission.

• Start as soon as possible — ideally within 24 hours, and no later than 72 hours after exposure.
• Not PBS-subsidised in Australia (private cost), but available from sexual health clinics, GP S100 HIV prescribers, and EDs for significant-risk exposures.
• Only prescribed when the risk of contracting HIV is high.
• Typically a 4-week course of 2 (or 3) antiretroviral drugs.

High-risk exposures warranting PEP:

• MSM with recent sexual contact or shared injecting equipment with a person who is HIV-positive and not on treatment (or detectable/unknown viral load), or of unknown HIV status.
• Anyone with recent sexual contact or shared injecting equipment with a person from a high-prevalence country, or who is HIV-positive with a detectable/ unknown viral load.
• Occupational exposure to a known-positive source not on treatment (or with a detectable/unknown viral load).

After completing PEP in someone at ongoing risk, consider transitioning to PrEP.