Which scenario is a contraindication to vaccination?

• A. Mild illness with fever under 38C.
• B. History of anaphylactic reaction to a previous vaccine or its component.
• C. Recent antibiotic use.
• D. Upcoming surgery.

Answer: (B)

A severe allergic reaction to a previous vaccine or to a component inside a vaccine is a true contraindication to giving that vaccine again. An anaphylactic reaction means the body could react explosively upon re-exposure, risking another life-threatening event. Because of this high risk, vaccination should be avoided until a healthcare professional assesses the allergy and determines safe alternatives or precautions.

Mild illness with a fever under 38°C, recent antibiotic use, and an upcoming surgery do not constitute contraindications. Vaccines can usually be given when a child is mildly ill, antibiotics don’t affect vaccine safety or effectiveness, and surgery does not require delaying routine vaccination unless there are other specific medical concerns.