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

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. This study aimed to reassess the risk of MMR vaccination in infants with egg allergy referred by healthcare workers. 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. 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 15.26 ± 29.64 kU/L. Skin prick test results were positive for egg allergens in 35 patients with a mean diameter of 3.12 ± 2.18 mm for 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. 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.