[Allergic reactions to vaccines].

Area of Science:

• Immunology
• Vaccinology
• Allergology

Context:

• Vaccine administration is a critical public health measure.
• Adverse events, including rare allergic reactions, require careful evaluation.
• Accurate diagnosis of vaccine allergy is essential for patient safety.

Purpose:

• To outline the diagnostic approach for suspected allergic reactions post-vaccination.
• To differentiate true vaccine allergy from other adverse events.
• To guide clinicians in managing patients with suspected vaccine component allergies.

Summary:

• Allergic reactions following vaccination are uncommon.
• Reactions are more frequently associated with vaccine excipients (e.g., gelatin, egg proteins) than active vaccine components.
• Evaluation by an allergist, including immediate-type allergy skin testing, is recommended for suspected cases.
• Negative skin tests indicate a very low risk of future allergic reactions, permitting vaccination.
• Positive skin tests may warrant using alternative vaccines or a graded vaccine administration approach.

Impact:

• Facilitates accurate diagnosis and management of vaccine allergies.
• Reduces unnecessary vaccine hesitancy by clarifying risks.
• Supports continued safe and effective vaccine programs.
• Provides a framework for allergists and immunologists in clinical practice.