Rabies Immunoglobulin (RIG) in Category 3 Exposures
Yes, rabies immunoglobulin (RIG) is required for ALL category 3 exposures, including small abrasions, unless the person has been previously vaccinated against rabies. 1
Definition of Category 3 Exposure
Category 3 exposures include: 2
- Any penetration of skin by teeth (bites), regardless of size or location
- Scratches or abrasions that break the skin
- Contamination of mucous membranes with saliva or potentially infectious material
- Any contact with bats where bite or mucous membrane exposure cannot be excluded
The size of the wound does not determine whether RIG is needed—the category of exposure does. 1, 2
Complete Post-Exposure Prophylaxis Protocol for Category 3
Immediate Wound Management
- Wash all wounds thoroughly with soap and water for approximately 15 minutes 3, 4, 5
- Irrigate with povidone-iodine solution if available 1, 3
- Administer tetanus prophylaxis as indicated 1
Passive Immunization (RIG) - Required for All Category 3
- Administer exactly 20 IU/kg body weight as a single dose on day 0 1, 4, 2
- Infiltrate the full dose of RIG thoroughly around and into ALL wounds if anatomically feasible 1, 2
- Any remaining volume should be injected intramuscularly at a site distant from vaccine administration 1, 2
- RIG can be given up through day 7 after the first vaccine dose if not given initially 1
- Never administer more than the recommended dose, as it can suppress active antibody production 1
Active Immunization (Vaccine)
- Administer rabies vaccine as a 4-dose series on days 0,3,7, and 14 3, 4, 2
- Give intramuscularly in the deltoid area for adults 1, 2
- For children, the anterolateral thigh is also acceptable 1, 2
- Never use the gluteal area—this results in lower antibody titers 1, 2
Exception: Previously Vaccinated Persons
The ONLY exception to RIG administration is for persons who have: 1
- Previously received complete pre-exposure or post-exposure vaccination with cell culture vaccine
- Documented rabies antibody titers from prior vaccination
These individuals receive only 2 doses of vaccine (days 0 and 3) and NO RIG 4
Critical Points About Small Abrasions
The combination of RIG and vaccine is recommended for both bite and nonbite exposures, regardless of the interval between exposure and initiation of treatment. 1 This explicitly includes small abrasions that break the skin. The rationale is that rabies virus can be transmitted through any break in the skin contaminated with saliva or infectious material. 2
Animal studies have demonstrated that while wound cleansing alone reduces rabies risk, the combination of wound care, RIG, and vaccine is nearly 100% effective when properly administered. 4 No failures have been documented in the United States since current cell culture biologics were licensed. 4
Common Pitfalls to Avoid
- Failing to infiltrate the full RIG dose around the wound when anatomically feasible—rare failures of post-exposure prophylaxis have been reported when smaller amounts were infiltrated at exposure sites 1
- Withholding RIG for "minor" category 3 exposures—the category of exposure, not wound size, determines treatment 1, 2
- Administering RIG in the same syringe or anatomical site as vaccine 1, 2
- Giving more than the recommended RIG dose, which can suppress antibody production 1