Reassessing the Risks of MMR Vaccination for Egg-Allergic Patients Referred by HealthcareWorkers; a Clinical Paradigm

Background: Egg allergy for the Measles-Mumps-Rubella (MMR) vaccine is still the cause of concern for many healthcare workers and families due to reactions such as anaphylaxis. Objectives: This study aimed to reassess the risk of MMR vaccination in infants with egg allergy referred by healthcare workers. Methods: This cross-sectional observational study was performed in a university-affiliated hospital in Istanbul, Turkey, between March 2017 and September 2018. The study patients were one-year-old infants who were candidates for MMR vaccination, and referred to our outpatient allergy clinic by healthcare workers due to egg allergy. The children were diagnosed with egg allergy by a pediatric allergist and then received the MMR vaccine. Results: Among 50 children aged one year, 19 (38%) were female, and 31 (62%) were male. The diagnosis was atopic dermatitis in 29 (58%) patients, urticaria in 18 (36%) patients, angioedema in 2 (4%) patients, and anaphylaxis in one (2%) patient. Fourteen (28%) patients had both egg and cow’s milk allergy. Four (8%) patients had egg, cow’s milk, and wheat allergy. The total IgE level was 119.80 213.43 IU/mL. Specific IgE levels for egg white were positive in 37 patients. Specific IgE levels for egg white were 15.2629.64 kU/L. Skin prick test results were positive for egg allergens in 35 patients with a mean diameter of 3.122.18mmfor egg yolk and 3.27 2.62 mm for egg white. None of the patients with egg allergy developed anaphylactic reaction and only one patient had urticaria within 5 min after vaccination. There was no correlation between specific IgE levels for egg white and diagnosis of the patients. Conclusions: MMR vaccine administration to children with egg allergy is safe. Life-threatening reactions to the MMR vaccine in patients with egg-allergy are very rare. It seems in cases of hypersensitivity reactions such as acute anaphylaxis events, the MMR vaccine needs to be administered in a hospital under the supervision of a pediatric allergist.