Rabies Vaccine Dosing
For post-exposure prophylaxis in previously unvaccinated persons, administer 1.0 mL of rabies vaccine (HDCV or PCECV) intramuscularly on days 0,3,7, and 14, combined with rabies immune globulin (20 IU/kg) on day 0—this same dose applies to all patients including children weighing less than 15 kg. 1
Post-Exposure Prophylaxis (PEP) Dosing
Previously Unvaccinated Persons
The ACIP guidelines establish a clear 4-dose regimen that superseded the older 5-dose schedule:
- Vaccine dose: 1.0 mL intramuscularly at each visit
- Schedule: Days 0,3,7, and 14
- Vaccine types: HDCV (human diploid cell vaccine) or PCECV (purified chick embryo cell vaccine)
- Critical point: Children receive the exact same 1.0 mL dose as adults—there is no dose reduction based on weight, including for children under 15 kg 1
Rabies Immune Globulin (HRIG)
Must be administered concurrently with the first vaccine dose:
- Dose: 20 IU/kg body weight (weight-based for all ages)
- Administration: Infiltrate as much as anatomically feasible around and into the wound(s); inject remaining volume intramuscularly at a site distant from vaccine administration
- Timing: Given on day 0, or up to day 7 if not initially administered
- Never: Administer in the same syringe or same anatomic site as the vaccine 1
Previously Vaccinated Persons
For those with documented prior rabies vaccination:
- Vaccine dose: 1.0 mL intramuscularly
- Schedule: Days 0 and 3 only (2 doses total)
- No HRIG: Do not administer immune globulin—it may inhibit the anamnestic response 1
Injection Site Considerations
Critical anatomic guidance to prevent vaccine failure:
- Adults and older children: Deltoid muscle only
- Younger children: Anterolateral thigh is acceptable
- Never use: Gluteal area—this site results in diminished immunologic response and has been associated with vaccine failures 1
Special Populations
Immunosuppressed Patients
Use a 5-dose schedule instead of the standard 4-dose regimen:
- Days 0,3,7,14, and 28
- Still use 1.0 mL per dose
- Still administer HRIG on day 0 1
This is the only population requiring the older 5-dose schedule, as immunocompromised individuals may not mount adequate immune responses with fewer doses.
Pre-Exposure Prophylaxis (PrEP)
While the question focuses on post-exposure dosing, for completeness:
- Standard regimen: 3 doses of 1.0 mL intramuscularly on days 0,7, and 21 or 28
- Alternative 2-dose regimens: Emerging evidence supports 2-dose schedules (days 0 and 7, or days 0 and 28) with adequate immune response 2, though 3-dose regimens remain standard in most guidelines
Key Clinical Pitfalls
Common errors to avoid:
Do not reduce vaccine dose for children: The 1.0 mL dose is the same regardless of age or weight—this is explicitly stated in ACIP guidelines and applies even to infants 1
Do not exceed recommended HRIG dose: More is not better—excessive HRIG can suppress active antibody production 1
Do not delay initiation: Begin PEP immediately after exposure assessment; the regimen works regardless of time interval between exposure and initiation 1
Do not give HRIG to previously vaccinated persons: This inhibits the rapid anamnestic response these patients should mount 1
Do not skip wound care: Thorough cleansing with soap and water (and virucidal agent like povidone-iodine if available) is an essential component of PEP 1
Evidence Quality
The 2010 ACIP recommendations 1 represent the authoritative U.S. guideline, published in MMWR and endorsed by the American Academy of Pediatrics 3. The 4-dose regimen has been validated as safe and effective when combined with appropriate wound care and HRIG administration 4. The reduction from 5 to 4 doses was based on immunogenicity data showing adequate antibody responses, with cost savings of approximately $16.6 million to the U.S. healthcare system without compromising protection 1.