A recent study has investigated the administration of influenza vaccines in patients with egg allergies. Guidelines for the 2017-2018 flu season have been updated following this study.
The annual influenza vaccine provides the most effective preventative measure against contracting and spreading the flu virus. The flu is a major cause of hospitalization and death in North America throughout the flu season. However, not all individuals can receive influenza vaccines. This population of patients included those with an egg allergy. Most influenza vaccines are grown in chicken eggs and may contain traces of egg protein. Researchers at the Section of Allergy and Clinical Immunology at the Children’s Hospital in Colorado, U.S. collected data regarding the safety of influenza vaccines in patients with an egg allergy and their results were recently published in the Annals of Allergy, Asthma, and Immunology.
The purpose of the investigation was to provide updated recommendations regarding the administration of influenza vaccines in patients with egg allergies. They reviewed 28 studies including over 4,300 patients with an egg allergy. Among those patients, 656 had severe anaphylactic reactions to egg ingestion. From this analysis, the Colorado researchers developed a comprehensive approach to the administration of influenza vaccines in egg-allergic patients, which provided necessary updates to the current influenza vaccine guidelines.
The Influenza Vaccine is Safe for Those with an Egg Allergy
The data indicated no increases in anaphylactic reactions following the administration of influenza vaccines in the study population. Minor reactions did occur. However, the rate of occurrence was no greater than the occurrence in the general population. In Canada, the guidelines do not recommend special precautions when administering influenza vaccines to patients with an egg allergy and there has not been any increase in side effects. Therefore, a history of egg allergy is no longer a contraindication to receiving any influenza vaccine and vaccine providers do not need to ask about egg allergy prior to vaccinating.
Two other questions were raised when setting the new practice recommendations. Non-egg based vaccines have been developed to allow egg-allergic patients to receive influenza vaccines. These vaccines are appropriate for use in this population but are no longer medically necessary. Patients can also have anaphylactic reactions to non-egg based vaccines. Finally, the researchers demonstrated that all influenza vaccines (including the non-live and live vaccines) are appropriate for use in patients without regard to their egg allergy status. Vaccine providers must still be prepared to treat anaphylactic reactions following vaccine administration as is the case for administering any vaccination.
These new recommendations have been included in the 2017-2018 influenza guidelines. The guidelines state that all influenza vaccines are safe for patients with an egg allergy. No special precautions are necessary when administering the vaccine to egg allergic patients, and non-egg-based vaccines are not medically necessary. Vaccine providers still need to be prepared for the rare events of anaphylactic shock following the administration of any vaccine.
Written by Jessica Caporuscio, PharmD
Reference: Greenhawt M, Turner PJ, Kelso JM. Administration of influenza vaccines to egg allergic recipients: A practice parameter update 2017. Ann Allergy Asthma Immunol. 2018.