What is the recommended post-exposure prophylaxis (PEP) for a patient who received a rabies vaccine 1 year ago and has been bitten by a cat that is not available for quarantine?

Post-Exposure Prophylaxis for Previously Vaccinated Rabies Patient with Cat Bite

For a patient who received rabies vaccination 1 year ago and has now been bitten by a cat that is unavailable for quarantine, the recommended post-exposure prophylaxis consists of 2 doses of rabies vaccine administered on days 0 and 3, without rabies immune globulin. 1, 2

Rationale for Treatment

• Previously vaccinated individuals (those who have received a complete pre-exposure or post-exposure vaccination series with cell culture vaccines) require a modified post-exposure prophylaxis regimen 1
• When an immunized person who was vaccinated using the recommended pre-exposure regimen or prior post-exposure regimen is exposed to rabies, they should receive only two intramuscular doses (1.0 mL each) of rabies vaccine 2
• The first dose should be administered immediately after exposure (day 0) and the second dose 3 days later 1, 2
• Rabies immune globulin (RIG) should NOT be administered in these cases, as it may inhibit the relative strength or rapidity of the expected anamnestic response 1, 2

Immunological Basis for Modified Protocol

• Previously vaccinated individuals develop a rapid anamnestic immune response upon re-exposure 1
• Studies have shown that persons who received primary vaccination with either PCECV or HDCV maintained adequate antibody titers (>0.5 IU/mL) at 1 year post-vaccination 1
• All persons tested at day 365 post-booster dose in both 1-dose and 2-dose booster groups had rabies virus neutralizing antibody titers >0.5 IU/mL, which is considered protective 1
• The rapid antibody response to a booster dose occurs with all persons exhibiting adequate antibody titers on days 7 and 14 post-booster dose 1

Wound Management

• Immediate and thorough washing of all bite wounds and scratches with soap and water for about 15 minutes is an essential component of rabies prevention 1, 2
• Where available, an iodine-containing or similarly virucidal topical preparation should be applied to the wound 2
• Tetanus prophylaxis and measures to control bacterial infection should be given as indicated 1, 2

Timing Considerations

• Post-exposure prophylaxis should be initiated as soon as possible after exposure to maximize effectiveness 3
• Even with delayed recognition of exposure, PEP should still be initiated, as incubation periods for rabies can be prolonged 3
• PEP is ineffective once clinical signs of rabies develop in the exposed person 3

Common Pitfalls to Avoid

• Administering rabies immune globulin to previously vaccinated individuals, which is unnecessary and may suppress the anamnestic antibody response 1, 2
• Delaying treatment while waiting for animal testing results when exposure to a potentially rabid animal has occurred 3
• Using the gluteal area for vaccine administration, which may result in lower neutralizing antibody titers 2
• Administering the full 5-dose (or 4-dose) regimen to previously vaccinated individuals, which is unnecessary 1, 2

Special Considerations

• If the immune status of a previously vaccinated person who did not receive the recommended regimen is not known, antibody levels should be checked 2
• If antibody levels of greater than 1:5 dilution by RFFIT can be demonstrated in a serum sample collected before vaccine is given, treatment can be discontinued after at least two doses of vaccine 2
• For immunosuppressed patients, the standard recommendation for post-exposure prophylaxis has not changed and should still comprise a full 5-dose vaccination regimen with RIG 1

Remember that rabies is nearly 100% fatal once clinical symptoms develop, so appropriate and timely post-exposure prophylaxis is critical 4.