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Single-dose flu vaccine safe among children with severe egg allergies

Children with egg allergies, even those with severe reactions, safely tolerated split and single doses of seasonal influenza vaccine in a recent study.

“Egg allergy should no longer be considered a condition that poses any greater risk in receiving influenza vaccine,” researcher Matthew J. Greenhawt, MD, assistant professor, University of Michigan Medical School, Division of Allergy and Clinical Immunology, and Infectious Diseases in Children editorial board member, told Healio.com. “We specifically demonstrated no difference in outcome between a single dose vs. a graded two-step challenge dosing style.”

Matthew J. Greenhawt

Between October 2010 and March 2012, Greenhawt and colleagues conducted a two-phase study at seven institutions to evaluate the safety of trivalent injectable influenza vaccine (TIV) in egg allergic children (EAC), including those with severe allergy or anaphylaxis. Among phase 1 participants, 45.1% of EAC had a history of anaphylaxis, while 77.6% of phase 2 participants previously had experienced similar anaphylaxis.

Thirty-one patients were randomly assigned to two groups in the phase 1 portion. Group A (n=14) received 0.1 mL of TIV and then the remainder of an age-appropriate dose (0.15 mL or 0.4 mL) 30 minutes later if no reactions were observed. Participants in group B (n=17) received one full age-appropriate dose of TIV 30 minutes after being injected with a 0.9% saline sham (0.1 mL) without consequence.

Phase 2 included 112 participants and consisted of a retrospective review of single-dose TIV among EAC (n=87) compared with split-dose administration (n=25). In both phases, Greenhawt said there were no allergic reactions following TIV. Three adverse events occurred during the phase 1 randomized controlled trial, none vaccine attributable.

“This study provides strong evidence that all egg allergic patients can safely receive the vaccine as a single dose without prior vaccine skin testing and should be observed for 30 minutes afterward in any medical setting,” Greenhawt concluded. “This includes primary care providers’ offices, where an allergic reaction could be recognized and treated should it occur.”