Post-Exposure Prophylaxis for Previously Vaccinated Persons
Previously vaccinated individuals exposed to rabies require only 2 doses of rabies vaccine (1.0 mL intramuscularly on days 0 and 3) and should NOT receive rabies immunoglobulin (HRIG). 1, 2, 3
Definition of "Previously Vaccinated"
You are considered previously vaccinated if you meet any of these criteria:
- Completed an ACIP-recommended pre-exposure prophylaxis regimen (3 doses) with cell-culture vaccines (HDCV, PCECV, or RVA) 1, 3
- Completed a prior post-exposure prophylaxis regimen with cell-culture vaccines 1
- Received any other rabies vaccine regimen AND have documented adequate rabies virus-neutralizing antibody response 1
The Simplified 2-Dose Protocol
Vaccine administration:
- First dose: 1.0 mL intramuscularly in the deltoid muscle immediately upon presentation (day 0) 1, 3
- Second dose: 1.0 mL intramuscularly in the deltoid muscle exactly 3 days later (day 3) 1, 3
- For young children, the anterolateral thigh is acceptable 2
- Never use the gluteal area - this produces inadequate antibody responses and is associated with vaccine failure 2, 3
Critical: No Immunoglobulin
HRIG is contraindicated in previously vaccinated persons because passive antibody inhibits the anamnestic (memory) immune response that develops rapidly after booster vaccination. 1, 2, 3 Previously vaccinated individuals develop a rapid and robust antibody response from immunologic memory alone, making HRIG both unnecessary and potentially harmful to the immune response. 3
Immediate Wound Care (Still Essential)
Regardless of vaccination status, perform these steps immediately:
- Wash all bite wounds and scratches thoroughly with soap and water for 15 minutes - this is the single most effective measure for preventing rabies 2, 4
- Irrigate with povidone-iodine solution if available 2
- Avoid suturing wounds when possible to prevent deeper viral inoculation 2
Special Population: Immunocompromised Patients
If the patient is immunocompromised, the protocol changes completely:
- Require a full 5-dose vaccine regimen (days 0,3,7,14, and 28) PLUS HRIG at 20 IU/kg on day 0, even if previously vaccinated 2
- Mandatory serologic testing 1-2 weeks after the final dose (day 42) to confirm adequate antibody response 2
- Consult public health officials when treating immunosuppressed previously vaccinated individuals 3
Do NOT Check Titers Before Treatment
Never delay treatment to check antibody titers - this is inappropriate and dangerous. 3 The 2-dose regimen should be administered immediately regardless of pre-exposure antibody levels, as previously vaccinated individuals develop rapid anamnestic responses regardless of their current titer. 3
Post-Treatment Serologic Testing
Routine antibody testing after completing PEP is NOT necessary for healthy patients. 1 However, if titers are obtained, serum collected 1-2 weeks after the last dose should completely neutralize challenge virus at least at a 1:5 dilution by RFFIT. 1
Common Pitfall to Avoid
The most dangerous error is administering HRIG to a previously vaccinated person. This wastes resources, adds unnecessary cost and injection site reactions, and most importantly inhibits the rapid protective immune response that the patient's immune system is primed to generate. 1, 3 When in doubt about vaccination history, treat as unvaccinated (4 doses plus HRIG) rather than risk inadequate protection.