Rabies Immunoglobulin Administration Timeline
Rabies immunoglobulin (RIG) should be administered on day 0 (the day the first vaccine dose is given), but if missed, it can still be given up to and including day 7 after the first vaccine dose. 1
Optimal Timing
RIG must be administered as soon as possible on day 0 when postexposure prophylaxis is initiated, given in conjunction with the first dose of rabies vaccine. 1
The ACIP guidelines explicitly state that if RIG was not administered when vaccination began on day 0, it can be administered up to and including day 7 of the postexposure prophylaxis series. 1
Beyond day 7, RIG is not indicated because an antibody response to the cell culture vaccine is presumed to have occurred by that time. 1, 2
Critical Rationale for the Day 7 Cutoff
RIG provides immediate passive rabies virus-neutralizing antibody coverage until the patient actively produces antibodies in response to vaccination. 1
By day 7-8, vaccine-induced active antibody production is expected to have begun, making passive immunization unnecessary and potentially counterproductive. 1
Administering RIG after day 7 can partially suppress active antibody production, which is why it should not be given beyond this timeframe for the same exposure. 1, 3
Administration Details
The dose is 20 IU/kg body weight, given only once (not repeated with subsequent vaccine doses). 1, 4, 2
As much of the RIG dose as anatomically feasible should be thoroughly infiltrated around and into the wound(s). 1
Any remaining volume should be injected intramuscularly at a site distant from vaccine administration. 1
Common Pitfalls to Avoid
Never administer RIG in the same syringe or same anatomical site as the first vaccine dose, as this can interfere with vaccine efficacy. 1, 5
Do not exceed the recommended 20 IU/kg dose, as higher doses can suppress active antibody production. 1, 3
RIG is not indicated for previously vaccinated persons (those who completed a full pre-exposure or postexposure prophylaxis regimen), as it may inhibit the anamnestic response. 1, 2
The day 7 deadline applies to the same exposure episode; a new separate exposure occurring after day 7 of an initial series would require its own RIG administration on day 0 of the new exposure. 4