What is the recommended dosage for an anti-rabies (rabies) vaccine?

Anti-Rabies Vaccine Dosage

For previously unvaccinated individuals exposed to rabies, administer 1.0 mL of rabies vaccine intramuscularly on days 0,3,7, and 14, combined with human rabies immune globulin (HRIG) at 20 IU/kg body weight on day 0. 1, 2

Post-Exposure Prophylaxis for Previously Unvaccinated Persons

Vaccine Regimen

• Administer four 1.0 mL doses of HDCV (human diploid cell vaccine) or PCECV (purified chick embryo cell vaccine) intramuscularly on days 0,3,7, and 14 1, 2
• Day 0 is defined as the day the first dose is administered, 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
• Never use the gluteal area—this produces inadequate antibody response and is associated with vaccine failure 1, 2

Human Rabies Immune Globulin (HRIG)

• Administer 20 IU/kg (0.133 mL/kg) body weight on day 0, ideally at the same time as the first vaccine dose 1, 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, 3
• HRIG can be given up to and including day 7 if not administered initially; beyond day 7, it is not indicated because antibody response to vaccine is presumed to have occurred 1, 2
• Never administer HRIG in the same syringe or anatomical site as the vaccine 1, 3
• Do not exceed the recommended 20 IU/kg dose—higher doses suppress active antibody production 1

Post-Exposure Prophylaxis for Previously Vaccinated Persons

• Previously vaccinated individuals require only 2 doses of vaccine (on days 0 and 3) and should NOT receive HRIG 1, 2, 4
• This applies to persons who have received complete pre-exposure or post-exposure prophylaxis with cell culture vaccines, or who have documented rabies virus neutralizing antibody titers 1

Special Populations

Immunocompromised Patients

• Administer five 1.0 mL doses on days 0,3,7,14, and 28, plus HRIG at 20 IU/kg on day 0, even if previously vaccinated 2, 4
• This includes patients on corticosteroids, other immunosuppressive agents, antimalarials, or those with HIV or chronic lymphoproliferative disorders 2
• Perform serologic testing 1-2 weeks after the final dose to confirm adequate antibody response (≥0.5 IU/mL or complete neutralization at 1:5 serum dilution) 2

Pediatric Patients

• Children receive the same vaccine dose volume (1.0 mL) and HRIG dose (20 IU/kg) as adults 2, 4
• Use the anterolateral thigh for vaccine administration in young children 1, 2

Critical Timing and Wound Care

• Initiate post-exposure prophylaxis as soon as possible after exposure, ideally within 24 hours 2, 4
• Treatment should begin immediately regardless of time elapsed since exposure—there is no absolute cutoff beyond which prophylaxis should be withheld 2
• Immediately wash all wounds thoroughly with soap and water for 15 minutes before any other intervention 2, 4, 3
• Follow with irrigation using a virucidal agent such as povidone-iodine solution if available 4, 3

Managing Schedule Deviations

• Delays of a few days for individual doses are unimportant; simply administer the missed dose when the patient presents and resume the schedule maintaining the same intervals 1, 5
• Most interruptions do not require restarting the entire series 1, 5
• For substantial deviations (weeks or more), assess immune status by serologic testing 7-14 days after the final dose 1, 5

Common Pitfalls to Avoid

• Never use the gluteal area for vaccine administration—this is associated with lower neutralizing antibody titers and vaccine failure 1, 2
• Never give HRIG to previously vaccinated persons—it will inhibit the anamnestic immune response 2, 4
• Never exceed the 20 IU/kg HRIG dose—excess amounts suppress active antibody production 1
• Do not use the standard 4-dose regimen for immunocompromised patients—they require the 5-dose schedule 2, 4