What is the post-exposure prophylaxis (PEP) regimen for someone suspected of being exposed to rabies?

Rabies Post-Exposure Prophylaxis Regimen

For previously unvaccinated individuals exposed to rabies, administer a 4-dose vaccine series (days 0,3,7, and 14) plus rabies immune globulin (RIG) on day 0; for previously vaccinated individuals, give only 2 vaccine doses (days 0 and 3) without RIG. 1

Previously Unvaccinated Persons

Complete PEP Protocol

• Administer 4 intramuscular doses of rabies vaccine (1.0 mL each): day 0 (immediately), day 3, day 7, and day 14 1
• Administer RIG 20 IU/kg on day 0 in conjunction with the first vaccine dose 2, 3
• Infiltrate the full calculated dose of RIG into and around all wounds if anatomically feasible; inject any remaining volume intramuscularly at a site distant from the vaccine injection 2, 3
• If RIG was not given on day 0, it can still be administered up through day 7 of the vaccine series 4, 2

Critical Wound Management

• Immediately wash all bite wounds and scratches with soap and water for approximately 15 minutes - this alone markedly reduces rabies transmission risk 5, 6
• Apply a viricidal agent (such as povidone-iodine) to the wound if available 3

Previously Vaccinated Persons

Modified Protocol

• Administer only 2 intramuscular vaccine doses (1.0 mL each): one immediately (day 0) and one on day 3 1, 5
• Do NOT administer RIG - previously vaccinated individuals develop a rapid anamnestic immune response, making RIG unnecessary and potentially counterproductive 1, 5
• "Previously vaccinated" means completion of a recommended pre-exposure or post-exposure regimen with a cell culture vaccine, or documented rabies virus neutralizing antibody titer 1, 2

Immunocompromised Patients

• Administer a 5-dose vaccine regimen (days 0,3,7,14, and 28) plus RIG for immunosuppressed individuals, even if previously vaccinated 5, 3
• This population requires the extended series due to potentially inadequate immune response 5

Timing Considerations

Urgency of Treatment

• PEP is a medical urgency, not an emergency - decisions should not be delayed, but brief assessment is appropriate 1, 4
• Initiate treatment as soon as possible after exposure to maximize effectiveness 5, 4
• Even with delayed recognition of exposure, still administer PEP regardless of time interval, provided the patient shows no clinical signs of rabies 4, 2
• The incubation period typically ranges from 2-6 weeks but can extend beyond 1 year in rare cases 4, 2

Administration Details

Injection Site and Technique

• Use the deltoid muscle for adults and older children; use the anterolateral thigh for young children 3
• Never use the gluteal area - this results in lower neutralizing antibody titers 3
• Avoid injection into or near blood vessels and nerves 3
• Administer vaccine and RIG at different anatomical sites 2, 3

Common Pitfalls to Avoid

• Do not delay treatment while awaiting animal testing results when exposure to high-risk species (bats, raccoons, skunks, foxes) has occurred 4, 2
• Do not administer RIG to previously vaccinated persons - this is unnecessary and wastes limited resources 1, 5
• Do not use the gluteal region for vaccine administration due to reduced immunogenicity 3
• Do not skip wound cleansing - this is an essential first step that significantly reduces transmission risk 5, 6

When to Discontinue PEP

• Stop prophylaxis if laboratory testing (direct fluorescent antibody test) confirms the animal was not rabid 3
• PEP becomes ineffective once clinical signs of rabies develop in the exposed person 4

Evidence Quality Note

The reduction from 5 doses to 4 doses for previously unvaccinated persons was based on comprehensive evidence from rabies pathogenesis data, animal models, human immunogenicity studies, and epidemiologic surveillance, demonstrating that 4 doses with RIG elicit adequate immune responses without the need for a fifth dose 1. This represents a consensus recommendation from the Advisory Committee on Immunization Practices (ACIP) adopted in 2010 1.