What is the post-exposure prophylaxis (PEP) treatment for rabies?

Rabies Post-Exposure Prophylaxis (PEP)

For Previously Unvaccinated Individuals

Post-exposure prophylaxis for rabies in previously unvaccinated persons consists of immediate wound care, human rabies immune globulin (HRIG) at 20 IU/kg infiltrated around the wound, and a 4-dose rabies vaccine series administered on days 0,3,7, and 14. 1, 2

Immediate Wound Management

• Wash all bite wounds and scratches immediately and thoroughly with soap and water for approximately 15 minutes, which markedly reduces rabies risk based on animal studies 1, 2, 3
• Irrigate with a virucidal agent such as povidone-iodine solution if available 2, 4
• Administer tetanus prophylaxis and antibiotics as indicated for bacterial infection control 1, 2
• Avoid suturing wounds when possible 1

Human Rabies Immune Globulin (HRIG)

• Administer HRIG at exactly 20 IU/kg body weight as a single dose on day 0 2, 3
• Infiltrate the full dose of HRIG thoroughly around and into all wounds if anatomically feasible, with any remaining volume injected intramuscularly at a site distant from the vaccine injection 2, 3
• HRIG should be administered through day 7 after the first vaccine dose; beyond day 7, it is not indicated since an antibody response to vaccine is presumed to have occurred 4

Rabies Vaccine Schedule

• Administer a 4-dose vaccine series on days 0,3,7, and 14 1, 2
• This represents an updated recommendation from the previous 5-dose regimen that was used through 2009 1
• Inject vaccine intramuscularly in the deltoid muscle for adults and older children, or the anterolateral thigh for infants and small children 3
• Never administer vaccine in the gluteal area, as this results in lower neutralizing antibody titers 2

For Previously Vaccinated Individuals

Previously vaccinated persons require only 2 doses of rabies vaccine on days 0 and 3, without HRIG. 5, 2

• Do not administer HRIG to previously vaccinated individuals, as it may blunt the rapid anamnestic antibody response 5, 2
• This modified regimen applies to persons who have ever received a complete pre-exposure or post-exposure vaccination series with a cell culture vaccine 1, 3
• Previously vaccinated individuals develop a rapid anamnestic immune response, with studies showing adequate antibody titers maintained at 1 year post-vaccination 5

Timing and Urgency

• PEP is a medical urgency, not a medical emergency, but decisions must not be delayed 1, 2
• Prophylaxis should be administered regardless of the length of delay, even months after exposure, provided the person shows no clinical signs of rabies 1, 6, 2
• Incubation periods exceeding 1 year have been documented in humans, making delayed treatment still effective 1, 6
• Begin treatment as soon as possible after exposure, ideally within 24 hours 4

Special Populations

• For immunosuppressed patients, use the full 5-dose vaccination regimen with HRIG 5
• Immunosuppressed persons should have their viral neutralizing antibody titers checked after completing any prophylaxis series 3

Efficacy and Safety

• The combination of wound care, HRIG, and vaccine is nearly 100% effective when properly administered 2, 7, 8
• No failures have been documented in the United States since current cell culture biologics were licensed, despite occasional improper administration 1, 2
• If laboratory testing confirms the exposing animal was not rabid, PEP can be discontinued 1, 3

Critical Pitfalls to Avoid

• Never delay PEP waiting for animal testing results if the animal is unavailable or died before completing a 10-day observation period 6
• The 10-day observation period for healthy dogs, cats, or ferrets is prospective, not retrospective—the animal must remain alive and healthy throughout 6
• Do not administer HRIG to previously vaccinated individuals 5, 2
• Do not inject vaccine in the gluteal region 2
• Do not administer HRIG and vaccine at the same anatomical site 2, 3