What is the recommended Post-Exposure Prophylaxis (PEP) treatment for rabies?

Rabies Post-Exposure Prophylaxis Treatment

For previously unvaccinated individuals exposed to rabies, immediately initiate a 4-dose vaccine regimen (days 0,3,7, and 14) combined with rabies immune globulin (RIG) at 20 IU/kg, along with thorough wound washing—this protocol is nearly 100% effective when administered promptly. 1, 2

Immediate Wound Care (First and Critical Step)

• Thoroughly wash all wounds with soap and water for 15 minutes immediately after exposure—this is perhaps the single most effective measure for preventing rabies infection and must be done before any other intervention. 2, 3, 4
• Apply a virucidal agent (such as iodine-containing solution) to the wound if available. 3, 5
• Administer tetanus prophylaxis and antibacterial measures as indicated. 3

Vaccine Regimen for Previously Unvaccinated Persons

• Administer 4 doses of rabies vaccine (HDCV or PCECV) at 1.0 mL intramuscularly on days 0,3,7, and 14. 1, 2, 3
• Day 0 is defined as the day the first dose is given, not necessarily the day of exposure. 2
• Inject in the deltoid muscle for adults and older children; use the anterolateral thigh for young children. 2, 3
• Never administer vaccine in the gluteal area—this produces inadequate antibody response and has been associated with PEP failures. 2, 3

Rabies Immune Globulin (RIG) Administration

• Administer RIG at 20 IU/kg body weight on day 0, ideally at the same time as the first vaccine dose. 2, 5
• Infiltrate the full dose of RIG around and into all wounds if anatomically feasible; administer any remaining volume intramuscularly at a site distant from vaccine administration. 2, 5
• Do not administer RIG in the same syringe or at the same anatomical site as the vaccine. 2, 3
• RIG can be given up to and including day 7 after the first vaccine dose if it was not administered initially. 2, 3
• Do not exceed the 20 IU/kg dose, as excessive amounts may suppress active antibody production. 2

Special Populations Requiring Modified Regimens

Immunocompromised Patients

• Use a 5-dose vaccine regimen (days 0,3,7,14, and 28) plus RIG at 20 IU/kg for all immunocompromised individuals, even if previously vaccinated. 1, 2
• Corticosteroids, immunosuppressive agents, antimalarials, and immunosuppressive illnesses can substantially reduce immune responses to rabies vaccines. 1
• Obtain serologic testing 7-14 days after the final dose to confirm adequate antibody response (≥0.5 IU/mL or complete virus neutralization at 1:5 dilution by RFFIT). 1, 2

Previously Vaccinated Persons

• Administer only 2 doses of vaccine (days 0 and 3) without RIG—these individuals develop a rapid anamnestic immune response. 1, 2, 6
• Do not give RIG to previously vaccinated persons, as it will inhibit the anamnestic response. 1, 2

Pediatric Patients

• Children receive the same vaccine dose volume (1.0 mL) as adults. 2
• Use the anterolateral thigh for vaccine administration in young children. 2, 3

Critical Timing Considerations

• Initiate PEP as soon as possible after exposure—delays of even hours matter significantly because rabies is nearly 100% fatal once clinical symptoms develop. 2
• There is no absolute cutoff beyond which PEP should be withheld—treatment should begin immediately upon recognition of exposure, even if weeks or months have elapsed. 2, 3
• The rabies incubation period typically ranges from 1-3 months but can extend from days to over a year. 1, 2
• If the exposing animal is proven negative by laboratory testing (direct fluorescent antibody test), PEP can be discontinued. 3

Common Pitfalls to Avoid

• Never use the gluteal area for vaccine administration—this is associated with vaccine failure due to inadequate immune response. 2, 3
• Never administer HRIG to previously vaccinated persons—this will inhibit the expected anamnestic response. 1, 2
• Do not forget to upgrade immunocompromised patients to the 5-dose regimen—the standard 4-dose schedule is inadequate for this population. 1, 2
• Do not exceed the recommended RIG dose of 20 IU/kg—excessive amounts may suppress active antibody production. 2
• Delays of a few days for individual vaccine doses are acceptable, though longer lapses require serologic assessment. 2

Post-Vaccination Serologic Testing

• Routine serologic testing is not necessary for healthy immunocompetent patients completing PEP. 1
• For immunosuppressed patients, obtain serum specimens 1-2 weeks after the final vaccine dose to document adequate antibody response. 1, 2
• Acceptable antibody response is complete virus neutralization at a 1:5 serum dilution by RFFIT. 1