What is the recommended post-exposure prophylaxis (PEP) schedule for a patient potentially exposed to rabies, considering their vaccination history and severity of exposure?

Rabies Post-Exposure Prophylaxis Schedule

For previously unvaccinated persons, administer a 4-dose rabies vaccine series on days 0,3,7, and 14, combined with human rabies immune globulin (HRIG) at 20 IU/kg on day 0, following immediate thorough wound washing. 1, 2, 3

Immediate Wound Management (Critical First Step)

• Wash all wounds thoroughly with soap and water for 15 minutes immediately—this is the single most effective measure for preventing rabies infection. 2, 4
• Follow with irrigation using a virucidal agent such as povidone-iodine solution if available. 1, 2
• Avoid suturing bite wounds when possible to prevent deeper contamination. 5

For Previously Unvaccinated Persons (Standard PEP)

Vaccine Administration

• Administer 4 doses of HDCV or PCECV, 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. 1, 2, 6
• Never use the gluteal area—this produces inadequate antibody response and is associated with vaccine failure. 1, 2, 6

HRIG Administration

• Administer HRIG at exactly 20 IU/kg body weight on day 0, ideally at the same time as the first vaccine dose. 1, 2, 3
• Infiltrate the full dose around and into the wound(s) if anatomically feasible; inject any remaining volume intramuscularly at a site distant from vaccine administration. 1, 2, 5
• Never administer HRIG in the same syringe or at the same anatomical site as the vaccine. 1, 2, 5
• HRIG can be given up to and including day 7 after the first vaccine dose if not initially administered. 2, 5
• Do not exceed 20 IU/kg—higher doses suppress active antibody production. 1, 6

For Previously Vaccinated Persons (Simplified PEP)

• Administer only 2 doses of vaccine (1.0 mL each) on days 0 and 3—do NOT give HRIG. 1, 2, 3
• This applies to persons who completed a recommended pre-exposure or post-exposure vaccination regimen with cell culture vaccine and have documented antibody response. 1, 2
• HRIG will inhibit the anamnestic immune response in previously vaccinated persons and should be avoided. 6, 5

For Immunocompromised Patients (Modified PEP)

• Administer a 5-dose vaccine regimen on days 0,3,7,14, and 28, plus HRIG at 20 IU/kg on day 0, even if previously vaccinated. 1, 2, 3
• This includes patients on corticosteroids, other immunosuppressive agents, antimalarials, or those with HIV, chronic lymphoproliferative leukemia, or other immunosuppressive illnesses. 2
• Mandatory serologic testing: Check rabies virus-neutralizing antibody by RFFIT 1-2 weeks after the final dose (day 42). 2
• An acceptable response is complete neutralization at 1:5 serum dilution. 2
• If no adequate response is detected, manage in consultation with public health officials. 2

Pediatric Considerations

• Children receive the same vaccine dose volume (1.0 mL) and HRIG dose (20 IU/kg) as adults. 1, 2, 6
• Use the anterolateral thigh for vaccine administration in young children. 1, 2

Timing and Compliance

• Initiate PEP as soon as possible after exposure, ideally within 24 hours, though there is no absolute cutoff—treatment should begin regardless of time elapsed. 2, 3
• Delays of a few days for individual doses are unimportant; resume the schedule maintaining the same intervals. 2, 3
• Treatment has been successfully implemented many months after exposure when recognition was delayed. 2, 5

Critical Pitfalls to Avoid

• Never use the gluteal area for vaccine administration—this is associated with inadequate immune response and vaccine failure. 1, 2, 6
• Never give HRIG to previously vaccinated immunocompetent persons—it will inhibit their rapid memory response. 2, 6, 5
• Never administer HRIG and vaccine in the same syringe or anatomical location. 1, 2, 6
• Never exceed 20 IU/kg of HRIG—higher doses suppress active antibody production. 1, 6
• Never forget to upgrade immunocompromised patients to the 5-dose regimen—the standard 4-dose schedule is inadequate for this population. 2

Efficacy

• When administered promptly and appropriately, this PEP regimen combining wound care, HRIG infiltration, and the vaccine series is nearly 100% effective in preventing human rabies. 2, 3
• The 4-dose schedule for immunocompetent persons is supported by overwhelming evidence showing it is safe, effective, and induces adequate long-lasting antibody response. 7