HIV Prophylaxis
For post-exposure prophylaxis (PEP), initiate bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF) as a single-tablet regimen within 24 hours of exposure (no later than 72 hours) and continue for 28 days. 1, 2
Post-Exposure Prophylaxis (PEP)
Timing and Initiation
- Start PEP immediately upon presentation, ideally within 24 hours but absolutely within 72 hours of exposure—efficacy drops significantly with delayed initiation. 1, 2, 3
- Do not delay the first dose while waiting for laboratory results. 1, 2
- PEP is ineffective if started beyond 72 hours after exposure. 1, 3
Preferred Regimens for Adults and Adolescents
The CDC recommends two preferred options: 1, 2, 3
First-line choice:
Alternative preferred regimen:
- Dolutegravir (DTG) plus tenofovir alafenamide (TAF) or tenofovir disoproxil fumarate (TDF) plus emtricitabine (FTC) or lamivudine (3TC) 1, 2, 3
Duration
- Complete the full 28-day course without interruption—incomplete adherence significantly reduces effectiveness. 1, 2, 3
- Provide the entire 28-day prescription at the initial visit to improve completion rates. 2
Indications for PEP
- Exposure occurred within the past 72 hours
- The exposure presents substantial HIV transmission risk (blood, blood-stained saliva, breast milk, genital secretions) 2, 3
- The source person has HIV without sustained viral suppression OR their HIV/viral suppression status is unknown 1
Case-by-case determination is needed when the source's HIV status is completely unknown. 1
Laboratory Testing Protocol
- Rapid HIV antigen/antibody combination test (point-of-care or laboratory-based)
- For persons with long-acting injectable PrEP exposure in past 12 months, add diagnostic HIV nucleic acid test (NAT) 1
- Assess medical comorbidities, current medications, and drug allergies 1, 2
At 4-6 weeks: 1
- Laboratory-based HIV Ag/Ab test plus diagnostic HIV NAT
- Laboratory-based HIV Ag/Ab combination immunoassay and diagnostic HIV NAT
Pediatric Considerations
For children ≤10 years: 2
- Preferred backbone: zidovudine (ZDV) + lamivudine (3TC)
- Preferred third drug: lopinavir/ritonavir (LPV/r)
Special Populations
Pregnant women: 2
- Administer PEP using the same regimens as other adults
- TMP-SMX is the recommended prophylactic agent for opportunistic infections
Sexual assault survivors: 2, 3
- Offer PEP promptly without waiting for risk assessment results
- Provide enhanced adherence support
Infants born to HIV-infected mothers: 2
- Administer antiretroviral prophylaxis
- For infants whose mothers received no prepartum or intrapartum antiretroviral therapy, provide 6 weeks of zidovudine
Pre-Exposure Prophylaxis (PrEP)
Transition from PEP to PrEP
For persons with anticipated repeat or ongoing HIV exposure risk, transition directly from PEP to PrEP after completing the 28-day course. 1, 2, 3
PrEP Efficacy Considerations
- Daily tenofovir disoproxil fumarate plus emtricitabine is safe and partially effective when combined with regular HIV monitoring and adherence counseling. 4
- Adherence requirements differ by anatomical site: minimum 6 of 7 doses weekly (85% adherence) protects female genital tract tissue, while 2 of 7 doses weekly (28% adherence) protects colorectal tissue. 5
Critical Pitfalls to Avoid
- Delaying PEP initiation beyond 72 hours eliminates effectiveness
- Waiting for laboratory results before starting the first dose
- Incomplete 28-day course significantly reduces effectiveness
- Inadequate follow-up for medication adherence and toxicity monitoring
- Always assess current medications for potential interactions before prescribing
Stigma barriers: 2
- Address stigma concerns proactively as they represent major barriers to PEP acceptance and adherence