From the Guidelines
Rabies HRIG should be administered as soon as possible after exposure, but it can be given up to 7 days after the first dose of rabies vaccine has been given, as recommended by the Advisory Committee on Immunization Practices 1. The administration of HRIG is crucial in providing immediate passive immunity against the rabies virus, while the vaccine stimulates the body's active immune response.
- The standard dose of HRIG is 20 IU/kg body weight, with as much as anatomically feasible infiltrated around and into the wound, and any remaining volume administered intramuscularly at a site distant from the vaccine injection 1.
- It's essential to administer HRIG only once during the post-exposure prophylaxis series to avoid interference with active antibody production stimulated by the vaccine.
- The recommendation for HRIG administration is based on reports of rare failures of postexposure prophylaxis when less than the full amount of HRIG was infiltrated at the exposure sites 1.
- Beyond the seventh day, HRIG is not indicated because an antibody response to cell culture vaccine is presumed to have occurred, and administering HRIG at this point could potentially interfere with the vaccine-induced immune response 1.
From the FDA Drug Label
Since vaccine-induced antibody appears within 1 week, HRIG is not indicated more than 7 days after initiating postexposure prophylaxis with RabAvert In the event that HRIG is not readily available for the initiation of treatment, it can be given through the seventh day after administration of the first dose of vaccine.
The rabies HRIG can be given until the seventh day after the first dose of vaccine. HRIG is not indicated beyond this time because an antibody response to the vaccine is presumed to have begun by then. 2
From the Research
Rabies HRIG Administration Timing
- The timing of rabies HRIG administration is crucial in post-exposure prophylaxis [(3,4)].
- According to the studies, HRIG should be administered as soon as possible after exposure, ideally within 7 days of the first rabies vaccine administration 3.
- There is no specific time limit mentioned in the studies for the administration of HRIG, but it is recommended to be given promptly after exposure [(4,5)].
- The World Health Organization recommends that HRIG be administered as soon as possible after exposure, and that it can be given up to 7 days after the first dose of vaccine [not explicitly stated in the provided studies, but implied by (3)].
HRIG Administration and Efficacy
- The efficacy of HRIG in preventing rabies has been demonstrated in several studies [(4,5,6)].
- HRIG provides immediate protection against rabies by neutralizing the virus at the site of exposure [(4,5)].
- The studies suggest that HRIG can be administered intramuscularly or intravenously, and that both routes are effective in providing protection against rabies [(5,6)].
Safety and Immunogenicity
- The safety and immunogenicity of HRIG have been evaluated in several studies [(4,6,7)].
- The studies suggest that HRIG is safe and well-tolerated, with minimal adverse reactions [(4,6,7)].
- HRIG has been shown to induce a rapid and adequate immune response, with high levels of neutralizing antibodies against the rabies virus [(6,7)].