What is the post-exposure prophylaxis (PEP) regimen for rabies, including the administration of rabies immunoglobulin (RIG) and anti-rabies vaccine?

Post-Exposure Prophylaxis for Rabies

Immediate Wound Management

Begin rabies post-exposure prophylaxis (PEP) immediately with thorough wound cleansing using soap and water for 15 minutes, followed by infiltration of rabies immune globulin (RIG) into and around all wounds, plus a 4-dose vaccine series on days 0,3,7, and 14 for previously unvaccinated individuals. 1, 2

• Wound irrigation is critical and has been shown in animal studies to markedly reduce rabies transmission risk 3
• Use a virucidal agent such as povidone-iodine solution if available 4
• Avoid aggressive scrubbing that damages tissue, but ensure complete removal of saliva and debris 2
• Do not suture wounds when possible, as closure may trap virus in tissue 2
• Administer tetanus prophylaxis and antibiotic prophylaxis as clinically indicated 3

Rabies Immune Globulin (RIG) Administration

Administer human RIG at exactly 20 IU/kg body weight (0.133 mL/kg) on day 0, infiltrating the full calculated dose around and into all wounds if anatomically feasible. 1, 2, 4

• The full dose of RIG should be thoroughly infiltrated in the area around and into the wounds; any remaining volume should be administered intramuscularly at a site distant from vaccine administration (deltoid or lateral thigh, NOT gluteal) 3, 2, 4
• This represents a critical update from older recommendations that suggested infiltrating only half the dose at the wound site 3
• RIG must be given only once, ideally simultaneously with the first vaccine dose 3, 2, 4
• If RIG was not given on day 0, it can still be administered up to and including day 7 after the first vaccine dose 3, 2, 4
• Beyond day 7, RIG is not indicated since an antibody response to vaccine is presumed to have occurred 3
• Never exceed the recommended 20 IU/kg dose, as higher doses can partially suppress active antibody production 3, 2

Vaccine Administration Protocol

Administer 1.0 mL of rabies vaccine (HDCV, RVA, or PCEC) intramuscularly in the deltoid area on days 0,3,7, and 14 for immunocompetent individuals. 1, 2

• For adults, always use the deltoid muscle 3, 4
• For children, the anterolateral aspect of the thigh is also acceptable 3
• Never use the gluteal area for vaccine injection, as this produces inadequate antibody titers and has been associated with vaccine failure 3, 2, 4
• Never administer RIG and vaccine in the same syringe or at the same anatomical site 3, 2, 4
• The first dose should be given as soon as possible after exposure, ideally within 24 hours 4

Special Populations and Modified Regimens

Previously Vaccinated Individuals

• Persons who have completed a full pre-exposure or post-exposure vaccination series with a cell culture vaccine require only 2 doses of vaccine on days 0 and 3 1, 2
• These individuals should NOT receive RIG, as it will inhibit the anamnestic antibody response 3, 2, 4

Immunocompromised Patients

• Immunocompromised individuals require a 5-dose vaccine regimen on days 0,3,7,14, and 28, plus RIG at 20 IU/kg 1, 2
• This extended regimen applies even if they were previously vaccinated 2

Critical Timing Considerations

• PEP should be initiated regardless of the interval from exposure, even if many months have passed, as long as clinical rabies symptoms have not yet appeared 1, 2
• There is no absolute cutoff beyond which PEP should be withheld 2
• Rabies incubation periods can range from days to over 1 year in humans, making delayed treatment still potentially life-saving 1
• Successful treatment has been documented even when initiated many months after exposure due to delayed recognition 3, 2

Exposure Risk Assessment

High-Risk Exposures Requiring Full PEP

• Any bite that penetrates the skin, especially to the face and hands 4
• Any physical contact with bats when bite or mucous membrane contact cannot be excluded, even if no visible bite is detected 4
• Scratches, abrasions, open wounds, or mucous membranes contaminated with saliva or brain tissue from a rabid animal 4

Low-Risk Exposures Not Requiring PEP

• Casual contact such as petting a rabid animal 4
• Contact with blood, urine, or feces of a rabid animal 4
• Exposure to dried material containing virus (virus is noninfectious when dry) 4

Common Pitfalls to Avoid

• Never delay PEP initiation while waiting for animal testing results if the animal is suspected rabid 4
• Never give RIG to previously vaccinated persons 3, 2
• Never use the gluteal region for vaccine or RIG injection due to risk of sciatic nerve injury and inadequate vaccine response 3, 4
• Never infiltrate less than the full calculated RIG dose at wound sites when anatomically feasible, as rare PEP failures have been reported with inadequate local infiltration 3
• Do not withhold PEP based on time elapsed since exposure 1, 2