How Real Are Allergic Reactions to Vaccine Components in Children? − Experiences of Clinicians

Abstract

Objective − Vaccine components have the potential to induce allergic reactions, although such reactions are infrequent, especially anaphylactic reactions, which are very rare (occurring at a rate of 1 per million vaccine doses). The objective of this study was to assess objectively the frequency of allergic reactions to vaccine components in children with suspected allergic reactions to vaccine components. Materials andMethods − We retrospectively analyzed the medical records of 209 patients aged 1 to 18 years with suspected allergic reactions to vaccine components, who underwent the standardized diagnostic procedures and tests to common allergens and vaccine components at Srebrnjak Children`s Hospital, Zagreb, Croatia. Results − Of the 209 children vaccinated in the hospital setting, only two (0.95%) developed side effects during their hospital stay, and 2.63% with a positive history of IgE mediated vaccine allergy were positive for one of the components of the vaccine. Local reactions to the vaccine were the most frequent adverse events in our patients. 62.6% of them were referred due to a positive history of egg protein allergy. Conclusion − Allergic reactions to vaccine components are rare and mild in most cases. In patients with a suggestive history, it is important to choose appropriate diagnostic tests to determine if vaccination can be performed safely. Only patients at risk of egg protein anaphylaxis generally require medically supervised vaccination in a hospital facility. Patients with a history or a documented and immediate allergic reaction (<4 h) require an allergy workup to avoid the risk of repeated anaphylaxis after further administration.