How should rabies immune globulin (RIG) be administered after a potential rabies exposure?

How to Administer Rabies Immunoglobulin

Infiltrate the full calculated dose (20 IU/kg body weight) of rabies immune globulin directly into and around all wounds as anatomically feasible, then inject any remaining volume intramuscularly at a site distant from the vaccine administration. 1

Dosing

• Calculate dose: 20 IU/kg (0.133 mL/kg) body weight for all age groups, including children 1
• Never exceed the recommended dose - excess RIG can suppress active antibody production from the vaccine 1

Administration Technique

Wound Infiltration (Primary Route)

• Thoroughly infiltrate the full calculated dose into and around all wounds whenever anatomically feasible 1
• This local infiltration is critical - rare PEP failures have been documented when insufficient RIG was infiltrated at exposure sites 1
• Volume requirements vary by wound size: approximately 1 mL for wounds <1 cm, 3 mL for 1-5 cm wounds, and 5 mL for wounds >5 cm 2

Remaining Volume

• Inject any remaining RIG volume intramuscularly at a site distant from vaccine administration 1
• Common IM sites include the gluteal region or thigh

Critical Timing Rules

• Administer RIG only once - give at the beginning of PEP (day 0) with the first vaccine dose 1
• If missed on day 0: RIG can still be given up to and including day 7 of the vaccine series 1
• After day 7: Do NOT give RIG - active antibody response to vaccine is presumed to have occurred by this point 1

Key Administration Prohibitions

• Never administer RIG in the same syringe as vaccine 1
• Never administer RIG in the same anatomical site as the first vaccine dose 1
• Note: Subsequent vaccine doses (days 3,7,14,28) can be given in the same anatomic location where RIG was administered 1

Who Should NOT Receive RIG

Do not give RIG to previously vaccinated persons who have:

• Completed a pre-exposure or post-exposure vaccination regimen with cell culture vaccine, OR
• Documented rabies virus neutralizing antibody titer from prior vaccination 1

These individuals receive vaccine only for post-exposure prophylaxis.

Common Pitfalls

Real-world adherence data reveals a critical gap: While healthcare systems demonstrate excellent adherence to patient selection (91%), dosing (98%), and timing (100%), only 56% of eligible patients actually receive proper wound infiltration 3. This represents a significant clinical failure point, as wound infiltration is specifically recommended based on documented PEP failures when inadequate RIG was infiltrated locally 1.

Delayed administration is common: Studies show mean delays of 8.7 days for RIG administration, particularly for exposures occurring abroad (9.6 days vs 6 days for domestic exposures) 4. Despite these delays, if within 7 days, still administer the RIG.

Essential Concurrent Measures

Before RIG administration:

• Thoroughly wash all wounds immediately with soap and copious water for approximately 15 minutes 1, 5
• Apply viricidal agent (iodine-containing preparation) when available 5
• Wound cleansing alone markedly reduces rabies likelihood in animal studies 1