Anaphylaxis from the influenza virus vaccine

Background: Allergic reactions to the influenza vaccine are uncommon and usually associated with sensitivity to egg or gelatin. The aim of this study was to report the case of anaphylaxis to the influenza vaccine. Methods: Allergy percutaneous skin testing, serum specific IgE testing and IgE immunoblotting were performed to the influenza vaccine, egg, and gelatin. Results: Percutaneous skin testing to the influenza vaccine and gelatin were positive and egg (white, whole, and yolk) was negative. Immunocap® serum-specific IgE testing to egg (white, whole, and yolk) and gelatin were negative (<0.35 kU/l). IgE immunoblots were performed with 2 cord blood serums and the patient's serum at a 1:20 dilution against 10 μg of the Fluzone influenza vaccine. The patient's IgE immunoblot showed a protein band at 100 kDa which is similar to the molecular weight of gelatin protein, a 68-kDa protein which is similar to the molecular weight of hemagglutinin protein from the influenza vaccine, and a 45-kDa protein band that is similar to the molecular weight of ovalbumin protein from chicken embryo/egg. Conclusion: Based on clinical symptoms, skin testing, Immunocap testing and immunoblot evaluation, we feel that our patient is allergic to the infectious agent in the influenza vaccine as well as gelatin and ovalbumin in egg.