Which condition is a contraindication for the DTaP vaccine?

• A. Seasonal allergies
• B. Mild fever after vaccination
• C. Active infection with varicella
• D. Neurologic disorders of unknown cause

Answer: (D)

Neurologic disorders of unknown cause are a contraindication for the DTaP vaccine because the vaccine’s safety profile in people with undiagnosed or unstable neurologic conditions is uncertain, and there is concern about the potential to trigger or worsen neurologic problems. When the cause of a neurologic issue isn’t known, withholding vaccination avoids introducing a possible additional risk while the condition is clarified or stabilized.

Seasonal allergies don’t raise the risk of a severe vaccine reaction, so they’re not a barrier to vaccination. A mild fever after vaccination is a common, transient reaction and does not represent a contraindication. Active varicella infection is a separate illness; while clinicians may consider delaying vaccines during a moderate or severe acute illness, it’s not a contraindication specific to DTaP.