Flu vaccine anaphylaxis is related to vaccine-specific IgE, not egg allergy

Published On; September 11, 2015

Influenza vaccines produced in embryonated eggs may pose a risk to egg allergy patients. However, patients experiencing influenza vaccine-associated anaphylaxis (IVA) do not always have egg allergy. In the 2011-2012 season, an unusually high incidence of IVA was reported in Japan.

In a study recently published in The Journal of Allergy and Clinical Immunology (JACI), Mizuho Nagao and her colleagues identified the cause of the “spike” in the flu vaccine anaphylaxis.  They collected blood samples of 19 IVA patients from various areas of Japan during the 2011-12 season and 25 age-matched control subjects, including 10 with egg allergy. Specific IgE to the trivalent vaccines of several manufacturers and HA proteins derived from both egg and cell culture were measured by ELISA. Antigen-induced basophil activation was evaluated by measuring CD203c expression by flow cytometry.

None of the patients with IVA had severe egg allergy. Specific-IgE antibodies to influenza vaccine antigens, whole vaccine products from different manufacturers, and hemaglutinin (HA) proteins (A H1, H3, and B) derived from both egg and cell culture were significantly elevated in patients with IVA compared with the controls. Influenza vaccine-induced CD203c expression in basophils was also highly enhanced in IVA, but not in the controls.

The authors state that anaphylaxis after administration of inactivated trivalent influenza vaccines may be due to specific IgE to an influenza vaccine component, not to contaminating egg protein.

The Journal of Allergy and Clinical Immunology (JACI) is an official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.

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