What is the recommended treatment for an individual with no history of rabies vaccination, exposed to rabies, possibly through an animal bite, specifically regarding the use of rabies immunoglobulin (RIG) and rabies vaccine?

Rabies Post-Exposure Prophylaxis for Unvaccinated Individuals

For an unvaccinated person exposed to rabies, immediately administer both rabies immune globulin (RIG) at 20 IU/kg body weight AND initiate a 4-dose rabies vaccine series on days 0,3,7, and 14, regardless of the time elapsed since exposure. 1, 2, 3

Immediate Wound Management (First Priority)

• Thoroughly wash all wounds with soap and water for 15 minutes as this is the single most effective measure to reduce rabies transmission risk 2
• Apply povidone-iodine solution or other virucidal agent after washing if available 2, 3
• Administer tetanus prophylaxis and bacterial infection control measures as clinically indicated 2, 3

Rabies Immune Globulin (RIG) Administration

Dosing and Timing

• Administer RIG at exactly 20 IU/kg body weight once on day 0 (the day the first vaccine dose is given) 2, 3, 4
• Do not exceed 20 IU/kg as higher doses may interfere with active antibody production from the vaccine 2, 4
• RIG can be given up to and including day 7 of the vaccine series if not administered on day 0, but is contraindicated after day 7 because active antibody production from vaccination is presumed to have occurred 1, 2, 4

Anatomical Administration Technique

• Infiltrate the full calculated dose thoroughly into and around all wounds if anatomically feasible 2, 3, 4
• Inject any remaining volume intramuscularly at a site distant from the vaccine administration site 2, 4
• Never administer RIG in the same syringe or anatomical site as the rabies vaccine 4

Common Pitfall: Only 56% of eligible patients receive proper wound infiltration with RIG despite guideline recommendations—ensure the full dose is infiltrated into wounds whenever anatomically possible 5

Rabies Vaccine Series

Standard 4-Dose Regimen (Previously Unvaccinated)

• Administer 1.0 mL intramuscularly on days 0,3,7, and 14 1, 2, 6
• Inject in the deltoid muscle for adults and older children; use anterolateral thigh for younger children 2
• Never administer vaccine in the gluteal area as this has been associated with treatment failures due to diminished immunologic response 1, 2, 3

Modified Regimen for Immunocompromised Patients

• Use a 5-dose vaccine schedule on days 0,3,7,14, and 28 plus RIG for immunocompromised individuals 1, 2

Previously Vaccinated Persons (Different Protocol)

• Administer only 2 vaccine doses on days 0 and 3 WITHOUT RIG for persons with documented prior complete rabies vaccination 1, 2, 4
• Do not give RIG to previously vaccinated persons as it is unnecessary and may inhibit the anamnestic immune response 2

Critical Timing Considerations

• PEP should be initiated regardless of the interval from exposure, even if months or over a year have passed, as long as clinical rabies symptoms have not appeared 1, 2
• Rabies incubation periods in humans can exceed 1 year, making delayed treatment still potentially life-saving 1, 2
• PEP is a medical urgency, not a medical emergency, but decisions must not be delayed 2

Common Pitfall: Do not withhold PEP while waiting for animal testing results—initiate treatment immediately and discontinue only if laboratory testing confirms the animal is not rabid 2

Animal-Specific Risk Assessment

High-Risk Animals (Immediate PEP)

• Wild carnivores (skunks, foxes, coyotes, raccoons, bobcats)—all bites must be considered rabies exposures and warrant immediate full PEP 2, 3
• Bats—regarded as rabid unless proven negative by laboratory testing 3

Domestic Dogs, Cats, and Ferrets

• Healthy animals available for 10-day observation: Do not begin prophylaxis unless the animal develops clinical signs of rabies during observation 7, 3
• Rabid or suspected rabid animals: Immediately begin full PEP 3
• Unknown/escaped animals: Initiate PEP immediately and consult public health officials 3

Low-Risk Animals

• Small rodents (rats, mice, squirrels, hamsters, guinea pigs, gerbils, chipmunks) and lagomorphs (rabbits, hares) almost never require PEP as they are rarely infected and have not transmitted rabies to humans in the United States 2, 3

Evidence Quality Note

The 4-dose vaccine schedule combined with RIG has overwhelming evidence for safety and effectiveness when used appropriately with timely wound care, inducing adequate long-lasting antibody response that neutralizes rabies virus and prevents disease 6