Infanrix Cannot Be Used for Adult DTP Vaccination
No, Infanrix (pediatric DTaP) should not be used for DTP vaccination in adults and is contraindicated in persons aged ≥7 years. 1, 2
Why Infanrix Is Inappropriate for Adults
Infanrix is a pediatric DTaP vaccine containing significantly higher quantities of diphtheria toxoid (25 Lf) and pertussis antigens (25 μg pertussis toxoid, 25 μg FHA, 8 μg pertactin) compared to adult Tdap formulations, which increases the risk of severe local reactions (Arthus reactions) in adults. 2
The CDC explicitly recommends against using DTaP in persons aged ≥7 years due to increased reactogenicity from the higher antigen content. 1, 2
Correct Vaccines for Adults
Adults requiring tetanus, diphtheria, and pertussis vaccination should receive Tdap (reduced-antigen formulation), not DTaP. 1, 3
Licensed Tdap Products for Adults:
Adacel (Tdap₅): Licensed for ages 10-64 years in the US, containing reduced quantities of all antigens (5 Lf tetanus, 2 Lf diphtheria, 2.5 μg pertussis toxoid). 1, 2
Boostrix (Tdap₃): Licensed for ages ≥10 years, containing 5 Lf tetanus, 2.5 Lf diphtheria, and 8 μg pertussis toxoid. 1, 2, 4
Adult Vaccination Algorithm
For adults aged 19-64 years who have never received Tdap:
- Administer a single dose of Tdap (Adacel preferred, but Boostrix acceptable) to replace the next scheduled Td booster, regardless of interval since last tetanus vaccination. 1, 3
- Follow with Td boosters every 10 years thereafter. 1, 3
For adults aged ≥65 years:
- Administer Tdap (Boostrix preferred for this age group, though either product is acceptable) if never previously received. 5
- The 2012 ACIP update extended Tdap recommendations to include all adults ≥65 years after safety and immunogenicity data demonstrated comparable adverse event profiles to younger adults. 5
What If Infanrix Is Inadvertently Given to an Adult?
If pediatric DTaP (Infanrix) is inadvertently administered to an adult aged ≥19 years, this dose should count as the Tdap dose, and the patient should not receive an additional dose of Tdap. 1, 2
- The patient should be informed of the inadvertent administration. 1
- Monitor for increased local reactions, particularly Arthus-type hypersensitivity (severe pain, swelling, induration developing 4-12 hours post-injection). 5
- Do not administer another tetanus-containing vaccine for at least 10 years unless required for wound management (>5 years for contaminated wounds). 5, 3
Key Clinical Pitfalls to Avoid
Never use DTaP formulations (including Infanrix) in persons aged ≥7 years—the higher antigen content significantly increases the risk of severe local reactions. 1, 2
Do not confuse product packaging—DTaP and Tdap packaging may appear similar; always review product labels before administration. 1
Avoid giving tetanus boosters more frequently than every 10 years for routine immunization to prevent Arthus reactions, which occur when diphtheria toxoid antibody titers remain elevated from recent vaccination. 5