Food allergy to gelatin in children with systemic immediate-type reactions, including anaphylaxis, to vaccines

Background: Anaphylaxis to measles-mumps-rubella vaccines has been reported. We have suspected that most such reactions are caused by gelatin contained in the vaccines. Objective: To confirm the relation between systemic allergic reactions to vaccines and the presence of anti-gelatin IgE, we measured anti-gelatin IgE in children who demonstrated allergy to gelatin-containing vaccines. Furthermore, to clarify the relation between allergic reactions to gelatin in vaccines and foods, we surveyed the occurrence of allergic reactions to gelatin-containing foods in the same children. Methods: Serum samples were taken from 26 children who had systemic immediate-type reactions, including anaphylactic shock, to vaccines and the same number of children without allergic reactions. Specific IgE to gelatin in these samples was measured. We then surveyed whether these children had allergic reactions to gelatin-containing foods before and after vaccination. Results: Twenty-four of the 26 children with allergic reactions to vaccines had anti-gelatin IgE ranging from 1.2 to 250 Ua/ml. Seven had allergic reactions on ingestion of gelatin-containing foods. Of these; two had reactions before vaccination, and five had reactions after vaccination. All the control children without allergic reactions to vaccines had no anti-gelatin IgE. Conclusion: We reconfirmed a strong relationship between systemic immediate-type allergic reactions, including anaphylaxis, to vaccines and the presence of specific IgE to gelatin. Moreover, some of the children also had allergic reactions to food gelatin before or after vaccination.