What is the protocol for administering post-exposure prophylaxis (PEP) for rabies, including rabies immunoglobulin (RIG) and rabies vaccine?

Rabies Post-Exposure Prophylaxis Protocol

Immediate Wound Management

Begin treatment immediately with thorough wound cleansing for 15 minutes using soap and water, followed by irrigation with a virucidal agent such as povidone-iodine solution—this single intervention markedly reduces rabies transmission risk and is perhaps the most effective preventive measure. 1, 2

• Avoid aggressive scrubbing that damages tissue, but ensure complete removal of saliva and debris from all wound surfaces 1
• Do not suture wounds when possible, as closure may trap virus in the tissue 1
• Administer tetanus prophylaxis and antibiotic prophylaxis as clinically indicated 1

Post-Exposure Prophylaxis Regimen for Previously Unvaccinated Persons

Rabies Immunoglobulin (RIG) Administration

Administer human rabies immunoglobulin (HRIG) at exactly 20 IU/kg body weight on day 0, infiltrating the full calculated dose around and into all wounds if anatomically feasible, with any remaining volume given intramuscularly at a site distant from the vaccine injection. 1, 2, 3

• HRIG must be given only once, ideally simultaneously with the first vaccine dose 1
• If HRIG was not given on day 0, it can still be administered up to and including day 7 of the vaccine series 1, 2
• Beyond day 7, HRIG is contraindicated because vaccine-induced antibody response has already begun 1
• Critical pitfall to avoid: Never administer HRIG in the same syringe or at the same anatomical site as the vaccine, as this may interfere with vaccine immunogenicity 1, 3
• Critical pitfall to avoid: Do not exceed the recommended 20 IU/kg dose, as higher doses can suppress active antibody production 1
• Insufficient wound infiltration has been associated with rare PEP failures—prioritize infiltrating wounds over distant IM injection 1, 4

Rabies Vaccine Administration

Administer 1.0 mL of human diploid cell vaccine (HDCV) or purified chick embryo cell vaccine (PCECV) intramuscularly on days 0,3,7, and 14 using a 4-dose regimen for immunocompetent individuals. 1, 2, 3

• Day 0 is defined as the day the first dose is administered, not necessarily the day of exposure 2
• Injection site for adults and older children: Deltoid muscle only 1, 5
• Injection site for infants and young children: Anterolateral thigh 1, 5
• Critical pitfall to avoid: Never use the gluteal area for vaccine administration, as this produces inadequate antibody titers and has been associated with vaccine failure 1, 3, 5

Special Populations

Immunocompromised Patients

Immunocompromised individuals must receive a 5-dose vaccine regimen (days 0,3,7,14, and 28) plus HRIG at 20 IU/kg, even if they were previously vaccinated. 2, 3

• Serologic testing 7-14 days after the final dose is recommended to confirm adequate antibody response 1, 5
• This population requires the extended regimen because the standard 4-dose schedule is inadequate 2

Previously Vaccinated Persons

Individuals who have completed a full pre-exposure or post-exposure vaccination series with a cell culture vaccine require only 2 doses of vaccine (days 0 and 3) and should NOT receive HRIG. 1, 2, 3, 5

• HRIG will inhibit the anamnestic antibody response in previously vaccinated persons 2
• This applies only to persons with documented complete vaccination history 1

Timing Considerations

Initiate PEP as soon as possible after exposure, ideally within 24 hours, though treatment remains indicated regardless of time elapsed since exposure—delays of even hours matter significantly given rabies' nearly 100% fatality rate once symptoms develop. 1, 2, 6

• There is no absolute cutoff beyond which PEP should be withheld 2
• Successful treatment has been documented even when initiated many months after exposure due to delayed recognition 1, 2
• Minor delays of a few days for individual vaccine doses are acceptable, but maintain the schedule as closely as possible 1, 2
• For substantial deviations (weeks or more), resume the schedule without restarting the series, and consider serologic testing 7-14 days after the final dose 1, 2

Common Pitfalls Summary

• Never use the gluteal area for vaccine injection 1, 3, 5
• Never give HRIG to previously vaccinated persons 2, 3
• Never administer HRIG and vaccine in the same syringe or anatomical site 1, 3
• Never exceed 20 IU/kg dose of HRIG 1
• Always prioritize infiltrating wounds with HRIG over distant IM injection 1, 4
• Always upgrade immunocompromised patients to the 5-dose regimen 2, 3