CDC Guidelines for HIV Post‑Exposure Prophylaxis (PEP) – 2025

Immediate Initiation

• Start PEP as soon as possible, ideally within 1 hour and no later than 72 hours after the exposure; do not wait for source testing, expert consultation, or selection of the optimal regimen. 1, 2

Eligibility Criteria

• PEP should be initiated only when all three conditions are satisfied:
  *These criteria are mandated by the CDC. 1, 2

• PEP must not be started if:
  *CDC guidance. 1, 2

Preferred Antiretroviral Regimens (28‑day Course)

• First‑line option: Bictegravir / emtricitabine / tenofovir alafenamide (BIC/FTC/TAF) as a single‑tablet regimen. 1, 2
• Alternative option: Dolutegravir + (tenofovir alafenamide or tenofovir disoproxil fumarate) + (emtricitabine or lamivudine). 1, 2
• These integrase‑inhibitor‑based regimens replace older zidovudine‑based options and constitute the CDC’s 2025 standard for PEP. 1, 2
• The full 28‑day course should be completed regardless of tolerability; discontinuation is allowed only if the source is later confirmed HIV‑negative. 1, 2

Baseline Testing Prior to First Dose

• Do not delay the first PEP dose while awaiting laboratory results. 1, 2
• Required baseline HIV testing: rapid point‑of‑care test or laboratory antigen/antibody combination assay. 1, 2

Follow‑Up Schedule

• 24‑hour check‑in (remote or in‑person) to assess adherence, tolerability, and answer questions. 1, 2
• 4–6 weeks post‑exposure: laboratory HIV antigen/antibody combination test plus diagnostic nucleic‑acid test (NAT). 1, 2
• 12 weeks post‑exposure (final visit): repeat HIV antigen/antibody combination immunoassay plus diagnostic NAT to confirm seronegative status; this shortened timeline reflects improved test sensitivity. 1, 2

Special Populations

Sexual Assault Survivors

• Provide a three‑drug PEP regimen regardless of the assailant’s characteristics and integrate STI prophylaxis and emergency contraception. 1, 2

Individuals Currently on PrEP

• If exposure occurs while adherent to daily oral PrEP, PEP may be unnecessary; expert consultation is recommended. 1, 2
• If exposure occurs after recent long‑acting injectable PrEP (cabotegravir), obtain baseline HIV NAT and consider alternative PEP regimens to avoid resistance. 1, 2

Transition from PEP to PrEP

• All PEP recipients should be counseled that pre‑exposure prophylaxis (PrEP) can reduce future HIV risk when ongoing exposure persists. 1, 2
• Offer PrEP options (daily oral tenofovir disoproxil fumarate/emtricitabine or long‑acting injectable cabotegravir) and develop a structured nPEP‑to‑PrEP transition plan for those who accept. 1, 2, 3

Avoiding Common Pitfalls

• Never postpone PEP while awaiting source HIV testing, specialist input, or optimal regimen selection; start immediately with a basic regimen if needed. 1, 2
• Do not use PEP as a substitute for PrEP in persons with repeated high‑risk exposures; instead, transition to PrEP. 1, 2

Timing and Initiation of HIV Post‑Exposure Prophylaxis after Needlestick Injury

Critical Timing Window

• Initiate the first PEP dose immediately—ideally within the first hour and no later than 72 hours after a percutaneous exposure—to maximize efficacy. The CDC 2025 guidelines state that effectiveness declines sharply with delay. [4][5][6][7]
• Primate studies show that starting PEP at 12 h or 36 h after exposure provides 100 % protection; starting at 72 h reduces protection to ≈ 67 %; initiating at day 3 results in viral rebound in 100 % of animals. These data support the urgent timing recommendation. [8][9]6

Immediate Initiation Regardless of Source Testing

• Do not wait for HIV test results of the source patient or for expert consultation before starting PEP; begin treatment immediately, using a basic regimen if the optimal regimen is uncertain. This is a strong CDC recommendation. 10

Preferred 28‑Day Regimens (Adults & Adolescents)

• Bictegravir / emtricitabine / tenofovir alafenamide (BIC/FTC/TAF) as a single‑tablet regimen.
• Dolutegravir‑based regimen: dolutegravir + (tenofovir alafenamide OR tenofovir disoproxil fumarate) + (emtricitabine OR lamivudine).

Indications for PEP

• Exposure occurred within the past 72 hours. 11
• The exposure involves a substantial risk for HIV transmission (percutaneous needlestick with blood or potentially infectious body fluids). 11
• The source is known to be HIV‑positive without sustained viral suppression, or the source’s HIV status/viral suppression is unknown. 6
• When any of the above conditions are met, CDC recommends initiating PEP. [7][8]12

Discontinuation Criteria

• Stop the 28‑day PEP course if the source is later confirmed HIV‑negative. [7][8]

Evidence Beyond the 72‑Hour Window

• Current evidence is insufficient to support initiating PEP after 72 hours post‑exposure. [5][9]
• Some experts suggest that, in select cases, the favorable risk‑benefit profile of modern antiretrovirals may justify a longer window, but this is not a formal recommendation. [5][9]
• For presentations after 72 hours, provide baseline HIV testing, counseling (including PrEP education), and arrange follow‑up HIV testing. 4

Follow‑Up Testing Protocol

• Baseline (Day 0): rapid or laboratory HIV antigen/antibody combination test; add HIV nucleic acid testing (NAT) if recent long‑acting injectable PrEP exposure is suspected. [12][5]
• Interim (4–6 weeks): laboratory HIV Ag/Ab test plus diagnostic NAT; testing may be deferred if PEP was started within 24 h and no doses were missed. [5][7]
• Final (12 weeks): laboratory HIV Ag/Ab combination immunoassay and diagnostic NAT to confirm seronegative status. 5

Common Pitfalls to Avoid

• Do not delay PEP while awaiting source testing, expert input, or optimal regimen selection; start with a basic regimen if needed. 10
• Do not test discarded needles for HIV contamination; this practice is not recommended and delays appropriate care. 11
• Ensure completion of the full 28‑day course, even if tolerability issues arise; modern regimens are markedly better tolerated than older zidovudine‑based therapies. [5][9]
• Re‑evaluate the exposed individual within 72 hours as additional source information becomes available and adjust the regimen if necessary. 10

Post‑Exposure Prophylaxis (PEP) Recommendations – CDC, 2025

Initiation and Timing

• The CDC recommends starting PEP as soon as possible, ideally within 1 hour and no later than 72 hours after a qualifying exposure, using a bictegravir / emtricitabine / tenofovir alafenamide (BIC/FTC/TAF) single‑tablet regimen for 28 days, without waiting for source‑person testing or laboratory results. 13

Eligibility Criteria (All Must Be Met)

• Exposure ≤ 72 hours ago, substantial risk exposure (sexual contact, needlestick, injection‑drug use, or blood/body‑fluid contact with non‑intact skin/mucosa), and source HIV‑positive without sustained viral suppression or source status unknown. 13

Situations in Which PEP Should NOT Be Initiated

• When the source is confirmed HIV‑negative.
• When the source is HIV‑positive with documented sustained viral suppression (undetectable viral load).
• When exposure occurred > 72 hours ago (evidence of benefit is insufficient). 13

Preferred Regimens (28‑Day Course)

• First‑line: BIC/FTC/TAF single‑tablet regimen.
• Alternative: Dolutegravir + (tenofovir alafenamide or tenofovir disoproxil fumarate) + (emtricitabine or lamivudine).
• Adherence: Complete the full 28‑day course regardless of tolerability; discontinue only if the source is later confirmed HIV‑negative. 13

Baseline Testing (Do Not Delay First Dose)

• Perform a rapid point‑of‑care HIV test or a laboratory antigen/antibody combination assay before the first dose.
• Never postpone PEP while awaiting test results. 13

Follow‑Up Schedule

• 24 hours: Remote or in‑person check‑in to assess adherence, tolerability, and answer questions.
• 4–6 weeks: Laboratory HIV antigen/antibody combination test plus diagnostic HIV nucleic‑acid testing (NAT).
• 12 weeks (final): Repeat HIV antigen/antibody combination immunoassay plus diagnostic NAT to confirm seronegative status. 13

Critical Pitfalls to Avoid

• Do not delay PEP for source testing, specialist input, or optimal regimen selection; start immediately with a basic regimen if needed. 13

Evidence from Primate Studies (Contextual)

• Primate data show that delaying PEP to 72 hours reduces protection to ≈ 67 %, and starting at day 3 results in 100 % viral rebound. (Animal‑model evidence; lower‑grade strength). 13

Transition from PEP to PrEP

• The CDC advises that all PEP recipients should be counseled that PrEP can reduce future HIV risk when ongoing exposure persists.
• Offer PrEP options (daily oral TDF/FTC or long‑acting injectable cabotegravir) and develop a structured nPEP‑to‑PrEP transition plan for those who accept. 13