What are the guidelines for post-exposure prophylaxis (PEP) for rabies?

Guidelines for Rabies Post-Exposure Prophylaxis (PEP)

Rabies post-exposure prophylaxis should include immediate wound cleansing, administration of human rabies immune globulin (HRIG), and a 4-dose vaccination schedule on days 0,3,7, and 14 for previously unvaccinated individuals. 1, 2

Components of Rabies PEP

Wound Management

• Immediate and thorough cleansing of all wounds with soap and water for 15 minutes, followed by irrigation with a virucidal agent, is the first essential step in preventing rabies infection 2, 3
• This simple measure alone has been shown to markedly reduce the likelihood of rabies transmission 4

Passive Immunization (HRIG)

• For previously unvaccinated individuals, human rabies immune globulin (HRIG) should be administered at 20 IU/kg body weight 1, 2
• The full dose of HRIG should be infiltrated around and into the wound(s) if anatomically feasible, with any remaining volume administered intramuscularly at a site distant from vaccine administration 2, 3
• HRIG is administered only once at the beginning of PEP to provide immediate antibodies until the patient develops their own response to the vaccine 1
• If not administered at the start of vaccination, HRIG can be given up to day 7 of the PEP series 1, 2
• HRIG should never be administered in the same syringe or anatomical site as the vaccine 1, 3

Active Immunization (Vaccine)

• For previously unvaccinated persons, a 4-dose regimen of human diploid cell vaccine (HDCV) or purified chick embryo cell vaccine (PCECV) is recommended 5, 1
• The vaccine schedule consists of 1.0 mL doses administered intramuscularly on days 0,3,7, and 14 5, 2
• The deltoid area is the only acceptable site for vaccination in adults and older children; for younger children, the anterolateral thigh may be used 1, 2
• Vaccine should never be administered in the gluteal area as this may result in diminished immune response 1, 2

Special Considerations

Previously Vaccinated Individuals

• Persons who have previously received complete pre-exposure or post-exposure vaccination require only 2 doses of vaccine (on days 0 and 3) and do not need HRIG administration 5, 1, 2

Immunocompromised Patients

• Immunosuppressed individuals should receive the full 5-dose regimen (days 0,3,7,14, and 28) 1, 2
• Serologic testing to confirm seroconversion is recommended for immunocompromised patients 2

Timing of PEP

• PEP should be initiated as soon as possible after exposure, though it is considered a medical urgency, not a medical emergency 5, 4
• Even with delayed recognition of exposure, PEP should still be initiated regardless of the time interval since exposure, as incubation periods of more than 1 year have been reported 2, 4
• PEP is ineffective once clinical signs of rabies develop 4

Risk Assessment for PEP

Type of Exposure

• Bite exposure: Any penetration of the skin by teeth constitutes a bite exposure 5, 3
• Nonbite exposure: Scratches, abrasions, open wounds, or mucous membranes contaminated with saliva or neural tissue from a rabid animal 3
• Bat exposures require special consideration - PEP should be considered for any physical contact with bats when bite or mucous membrane contact cannot be excluded 3
• Casual contact (petting a rabid animal) or contact with blood, urine, or feces does not constitute an exposure requiring PEP 3

Animal Factors

• PEP is always cost-effective when a patient is bitten by an animal that has tested positive for rabies 5
• PEP is also cost-effective when a patient is bitten by a reservoir or vector species (e.g., skunk, raccoon, bat, fox in the US; dog in countries with dog variant rabies), even if the animal is not available for testing 5
• The decision to initiate PEP also depends on the availability of the exposing animal for observation or rabies testing 5

Common Pitfalls to Avoid

• Delaying treatment while waiting for animal testing results when exposure to high-risk species has occurred 4
• Administering vaccine in the gluteal area, which can result in reduced immune response 1, 2
• Failing to properly infiltrate HRIG into and around all wounds 2, 3
• Administering HRIG and vaccine in the same anatomical site 1, 3
• Neglecting thorough wound cleansing, which is a crucial first step in prevention 2, 3

When administered promptly and appropriately, rabies PEP is nearly 100% effective in preventing human rabies 2, 6. The current 4-dose schedule represents an evolution from previous 5-dose and 6-dose regimens, providing cost savings while maintaining efficacy 1.