What is the protocol for rabies post-exposure prophylaxis (PEP) with rabies immunoglobulin (RIG)?

Rabies Post-Exposure Prophylaxis with RIG Protocol

For previously unvaccinated persons with rabies exposure, administer human rabies immunoglobulin (HRIG) at 20 IU/kg body weight on day 0 along with a 4-dose vaccine series on days 0,3,7, and 14, with the full HRIG dose infiltrated around and into all wounds when anatomically feasible. 1, 2, 3

Immediate Wound Management

• Thoroughly wash all wounds with soap and water for 15 minutes immediately upon presentation — this single intervention markedly reduces rabies likelihood in animal studies and is perhaps the most effective preventive measure. 1, 2, 4, 5
• Apply a virucidal agent such as povidone-iodine solution to irrigate wounds after washing when available. 2, 3
• Assess for tetanus prophylaxis needs and bacterial infection risk. 1

HRIG Administration Protocol

Dosing and Timing

• Calculate HRIG dose at exactly 20 IU/kg (0.133 mL/kg) body weight — this formula applies to all age groups including children. 1, 2, 3
• Administer HRIG on day 0 (same day as first vaccine dose) ideally, but it can be given up to and including day 7 of the vaccine series. 1, 3
• Beyond day 7, do not administer HRIG because vaccine-induced antibody response is presumed to have occurred. 1

Anatomical Administration Technique

• Infiltrate the full calculated HRIG dose thoroughly around and into all wound sites when anatomically feasible — failure to adequately infiltrate wounds has been associated with rare PEP failures. 1, 2, 3, 6
• Inject any remaining HRIG volume intramuscularly at a site distant from vaccine administration (deltoid or lateral thigh, never gluteal region). 1, 3
• Never administer HRIG in the same syringe or at the same anatomical site as the first vaccine dose. 1, 3
• Do not exceed the recommended 20 IU/kg dose, as higher doses can partially suppress active antibody production. 1, 2

Vaccine Administration Protocol

Standard 4-Dose Regimen (Previously Unvaccinated)

• Administer 1.0 mL doses of human diploid cell vaccine (HDCV) or purified chick embryo cell vaccine (PCECV) intramuscularly on days 0,3,7, and 14. 1, 2, 4
• Day 0 is defined as the day the first vaccine dose is administered, not necessarily the exposure date. 1, 4
• Inject in the deltoid muscle for adults and older children; use anterolateral thigh for young children and infants. 1, 3
• Never use the gluteal area — this produces inadequate antibody response. 1, 7, 4

Modified Regimen for Immunocompromised Patients

• Administer a 5-dose regimen on days 0,3,7,14, and 28 for immunosuppressed individuals. 2, 4
• Consider serologic testing 7-14 days after the final dose to confirm adequate antibody response in this population. 1, 4

Previously Vaccinated Persons

• Administer only 2 vaccine doses (1.0 mL each) on days 0 and 3 — do not give HRIG. 1, 7, 4
• This applies to persons with documented prior complete pre-exposure or post-exposure vaccination with cell culture vaccines. 1
• HRIG administration in previously vaccinated persons may interfere with the anamnestic antibody response. 1, 7

Critical Timing Considerations

• Initiate PEP as soon as possible after exposure, ideally within 24 hours — rabies is nearly 100% fatal once clinical symptoms develop. 4, 3
• PEP remains indicated regardless of delay, even if weeks or months have elapsed since exposure, provided the patient shows no clinical signs of rabies. 1, 4
• Minor delays of a few days between individual vaccine doses are acceptable and do not require restarting the series. 4
• For substantial schedule deviations (weeks or more), assess immune status by serologic testing 7-14 days after the final dose. 4

Common Pitfalls to Avoid

• Insufficient wound infiltration: Only 56% of eligible patients receive proper HRIG infiltration at wound sites in real-world practice — ensure the full dose reaches all wounds. 6
• Incorrect anatomical site: Never administer vaccine in the gluteal region due to risk of sciatic nerve injury and diminished immune response. 1, 4, 3
• Excessive HRIG dosing: Do not exceed 20 IU/kg as this suppresses active antibody production. 1, 2
• Administering HRIG to previously vaccinated persons: This is unnecessary and may inhibit the anamnestic response. 1, 7
• Delaying treatment for animal observation: Begin PEP immediately for high-risk exposures (bats, wild carnivores) without waiting for animal testing results. 1, 3
• Missing bat exposures: Bat bites may be minor and undetected — consider PEP for any physical bat contact when bite cannot be excluded. 7, 3

Exposure Category Assessment

When administered correctly and promptly, this combined HRIG and vaccine regimen is nearly 100% effective in preventing human rabies. 4, 8 No PEP failures have been documented in the United States when current biologics are properly administered. 1