Can a rabies booster dose be given intradermally to a patient who has previously completed a primary rabies vaccination series?

Intradermal Rabies Booster for Previously Vaccinated Individuals

Yes, a rabies booster dose can be given intradermally to previously vaccinated individuals, but only with HDCV (human diploid cell vaccine) using the FDA-approved 0.1 mL intradermal formulation (Imovax Rabies I.D.), and only for preexposure booster situations—NOT for postexposure prophylaxis. 1

Critical Distinction: Preexposure vs. Postexposure Context

For Preexposure Booster Vaccination (Routine Boosters)

• One 0.1-mL intradermal dose of HDCV is approved and recommended for routine preexposure booster vaccination in previously vaccinated individuals 1
• The intradermal dose should be administered in the deltoid area (lateral aspect of upper arm) 1
• This applies to high-risk individuals requiring periodic boosters (laboratory workers, veterinarians, spelunkers) 1
• Both IM and ID routes are acceptable for preexposure boosters 1

For Postexposure Prophylaxis (After Rabies Exposure)

• Intradermal administration is NOT recommended for postexposure prophylaxis in previously vaccinated individuals 2
• The CDC explicitly recommends two 1.0-mL intramuscular doses (days 0 and 3) for postexposure treatment 1, 2
• This IM-only recommendation for postexposure treatment ensures rapid, reliable protection when mortality is at stake 2

Vaccine-Specific Restrictions

Only HDCV is approved for intradermal administration:

• HDCV (Imovax Rabies I.D.) has FDA approval for ID use since 1986 1
• RVA (rabies vaccine adsorbed) and PCEC (purified chick embryo cell vaccine) are NOT approved for intradermal use and should never be given ID 1
• The 1.0-mL vial of HDCV is not approved for multidose ID use 1

Important Contraindications for Intradermal Route

Antimalarial Drug Interactions

• HDCV should NOT be administered intradermally to persons taking chloroquine or structurally related antimalarials (e.g., mefloquine) 1
• These drugs decrease antibody response to concomitantly administered intradermal HDCV 1
• For travelers to malaria-endemic areas requiring both rabies prophylaxis and antimalarials:
  • Either complete the 3-dose ID series at least 1 month before starting antimalarials 1
  • Or use the IM regimen instead, which provides sufficient safety margin 1

Immunosuppressed Individuals

• Immunosuppressed persons should have antibody titers checked after vaccination regardless of route 1, 3
• Consider IM route for more reliable immune response in this population 1

Evidence Supporting Intradermal Boosters

Research demonstrates that intradermal boosters produce adequate immune responses:

• Cross-over studies show equivalent anamnestic responses whether switching from IM to ID or vice versa for booster doses 4
• Four-site intradermal booster regimens (using one-fifth diluent volume) produced significantly higher antibody titers than conventional IM boosters in some studies 5
• However, some data suggest lower early anamnestic responses with ID preexposure series, particularly in the first 5 days post-booster 6, 7

Practical Algorithm for Decision-Making

Use intradermal booster IF:

1. Patient needs routine preexposure booster (not postexposure)
2. HDCV (Imovax Rabies I.D.) is available
3. Patient is NOT taking chloroquine or related antimalarials
4. Patient is NOT immunosuppressed (or has documented adequate titers)

Use intramuscular booster IF:

1. Postexposure prophylaxis is needed (always IM) 2
2. Only RVA or PCEC vaccines are available 1
3. Patient is taking antimalarial drugs 1
4. Patient is immunosuppressed 1
5. Intradermal formulation is unavailable

Common Pitfalls to Avoid

• Never use intradermal route for postexposure prophylaxis—this is the most critical error that could result in rabies death 2
• Do not attempt to divide the 1.0-mL vial for multiple ID doses—only the pre-packaged 0.1-mL formulation is approved 1
• Do not use RVA or PCEC intradermally under any circumstances 1
• Do not give ID boosters to patients on antimalarials without switching to IM route 1