What is the recommended treatment for rabies exposure in children, including the administration of rabies vaccine (e.g. Imovax (human diploid cell vaccine) or RabAvert (purified chick embryo cell vaccine)) and rabies immune globulin (RIG)?

Rabies Post-Exposure Prophylaxis in Children

Primary Recommendation

Children exposed to rabies who have never been vaccinated should receive both human rabies immunoglobulin (HRIG) at 20 IU/kg and a 4-dose vaccine series (days 0,3,7, and 14), while previously vaccinated children require only 2 vaccine doses (days 0 and 3) without HRIG. 1, 2

Immediate Wound Management

Before any immunologic intervention, wound care is critical:

• Wash all wounds thoroughly with soap and water for 15 minutes to mechanically remove virus from the exposure site 1, 2
• Irrigate with a virucidal agent such as povidone-iodine if available 1, 2
• Avoid suturing wounds when possible, as closure may trap virus in tissue 1
• Administer tetanus prophylaxis and antibiotics as clinically indicated 1, 3

Post-Exposure Prophylaxis Regimen for Previously Unvaccinated Children

Human Rabies Immunoglobulin (HRIG)

• Administer exactly 20 IU/kg body weight on day 0 only - this formula applies to all pediatric age groups 4, 1, 5, 2
• Infiltrate the full calculated dose around and into all wounds if anatomically feasible 1, 5, 2
• Any remaining volume that cannot be infiltrated into wounds should be injected intramuscularly at a site distant from vaccine administration 5, 3
• Never administer HRIG in the same syringe or anatomical site as the vaccine, as this interferes with immunogenicity 1, 5
• If HRIG was not given on day 0, it can still be administered up to and including day 7 after the first vaccine dose 1, 5, 2
• Beyond day 7, HRIG is not indicated as antibody response to vaccine is presumed to have occurred 1, 5

Rabies Vaccine

• Administer 1.0 mL intramuscularly on days 0,3,7, and 14 for immunocompetent children 1, 2
• For children, inject in the deltoid area (or anterolateral thigh in young children) 4, 2
• Never use the gluteal area for vaccine injection - this produces inadequate antibody titers and has been associated with vaccine failure 4, 1, 2
• Both human diploid cell vaccine (HDCV/Imovax) and purified chick embryo cell vaccine (PCECV/RabAvert) are acceptable options 1, 6

A recent 2021 pediatric study demonstrated that 93.3% of children achieved protective antibody levels (≥0.5 IU/mL) by day 14, with no serious adverse events, rabies infections, or deaths reported 7.

Special Populations

Immunocompromised Children

• Use a 5-dose vaccine regimen (days 0,3,7,14, and 28) plus HRIG at 20 IU/kg, even if previously vaccinated 1, 2
• Consider serologic testing 7-14 days after the last dose to ensure adequate seroconversion 2

Previously Vaccinated Children

• Administer only 2 doses of vaccine on days 0 and 3 1, 2, 3
• Do NOT give HRIG to previously vaccinated children - it will inhibit the anamnestic antibody response and is contraindicated 1, 5, 2

This applies to children who have completed either a full pre-exposure or post-exposure vaccination series with a cell culture vaccine 1, 2.

Timing Considerations

• Initiate post-exposure prophylaxis as soon as possible after exposure, ideally within 24 hours 1, 2
• However, there is no absolute cutoff - treatment remains indicated regardless of time elapsed since exposure 1
• Successful treatment has been documented even when initiated many months after delayed recognition of exposure 1, 3

Critical Pitfalls to Avoid

1. Never exceed the 20 IU/kg dose of HRIG - higher doses can suppress active antibody production 4, 1, 5, 2

2. Never inject vaccine in the gluteal area - this results in inadequate immune response and has been associated with treatment failures 4, 1, 2

3. Never give HRIG to previously vaccinated children - it will blunt their rapid memory response to rabies antigen 1, 5, 2, 3

4. Never delay wound cleaning - immediate mechanical removal of virus is the single most effective preventive measure 1, 2

5. Never administer HRIG and vaccine at the same anatomical site - maintain separate injection sites 1, 5, 3

Safety Profile in Children

Rabies post-exposure prophylaxis is well-tolerated in pediatric patients. In a 2021 prospective study of 30 children, 70% experienced mild treatment-emergent adverse events, with only 40% deemed treatment-related, and all were mild in severity 7. Historical data from Thai children exposed to rabid animals showed mild local reactions in only 1.5% of HDCV doses and similar safety with purified Vero cell vaccine 6.