What is the post-exposure prophylaxis (PEP) for a cat bite with potential rabies transmission?

Post-Exposure Prophylaxis for Cat Bites

Initiate rabies post-exposure prophylaxis (PEP) immediately with both rabies immune globulin (RIG) and a 4-dose vaccine series if the cat's rabies vaccination status is unknown or the animal cannot be observed for 10 days. 1

Risk Assessment for Cat Bites

• Any penetration of skin by teeth constitutes a bite exposure requiring evaluation for rabies PEP, regardless of the severity of visible trauma 2
• Cat bites carry a risk of rabies transmission estimated at approximately 0.001 (1 in 1,000) without PEP 3
• Cats are considered domestic animals that can be observed, but if unavailable for observation or of unknown vaccination status, they must be treated as potentially rabid 1, 4

When to Initiate PEP

Start PEP immediately if:

• The cat is unavailable for observation (escaped, stray, or owner refuses observation) 1, 4
• The cat's rabies vaccination status is unknown or inadequately documented 1
• The cat shows any signs of illness during the 10-day observation period 4, 5
• The cat dies before completing the 10-day observation period 6

Defer PEP only if:

• The cat is healthy, available, and can be observed for 10 days 4, 5
• During this observation period, begin PEP immediately at the first sign of rabies-like illness in the cat 4, 5
• If the cat remains healthy for the full 10 days, PEP is not needed 4, 5

Complete PEP Protocol for Previously Unvaccinated Persons

Immediate Wound Care

• Wash and flush the wound thoroughly with soap and water for approximately 15 minutes as soon as possible after the bite 4, 7
• Apply an iodine-containing or similarly viricidal topical preparation to the wound if available 4
• Administer tetanus prophylaxis and antibiotics as indicated for bacterial infection control 4

Rabies Immune Globulin (RIG)

• Administer RIG at a dose of 20 IU/kg body weight on day 0 (the day PEP is initiated) 1, 4
• Infiltrate as much of the dose as anatomically feasible into and around the wound(s) 1, 4
• Inject any remaining volume intramuscularly at a site distant from the vaccine injection site 6

Rabies Vaccine Series

• Administer a 4-dose vaccine series (human diploid cell vaccine [HDCV] or purified chick embryo cell vaccine [PCECV]) at 1.0 mL intramuscularly on days 0,3,7, and 14 1
• Inject vaccine in the deltoid muscle in adults (never in the gluteal area, as this has been associated with PEP failures) 6, 5
• The 4-dose schedule is the current standard, replacing the previous 5-dose regimen 1

Critical Timing Considerations

• PEP should be administered regardless of the length of delay from the time of exposure, as long as the person shows no clinical signs of rabies 1, 6
• Rabies incubation periods in humans can exceed 1 year, making delayed treatment still potentially life-saving 6, 8
• PEP is considered a "medical urgency, not a medical emergency"—it should be initiated as soon as possible but is effective even when delayed 6

Special Circumstances

Previously Vaccinated Persons

• If the person has previously received a complete rabies vaccination series (pre-exposure or post-exposure), administer only 2 doses of vaccine on days 0 and 3, without RIG 8, 4

Immunocompromised Persons

• Use a 5-dose vaccine regimen (days 0,3,7,14,28) plus RIG for immunocompromised individuals 8

Common Pitfalls to Avoid

• Do not wait for laboratory confirmation before starting PEP if the cat is unavailable—the animal must be tested or observed prospectively, not retrospectively 6
• Do not administer vaccine in the gluteal area—this route has been associated with treatment failures 6, 5
• Do not omit RIG in previously unvaccinated persons, as the combination of RIG and vaccine is essential for adequate protection 4, 5
• Do not discontinue PEP prematurely unless appropriate laboratory testing (direct fluorescent antibody test) confirms the animal was not rabid 4, 5

Non-Bite Exposures

• Licks on intact skin, petting, or handling the animal do not constitute exposures and do not require PEP 2, 4
• Contamination of open wounds, scratches, or mucous membranes with saliva from a potentially rabid cat does constitute a nonbite exposure requiring the same full PEP protocol 2, 4