Recommendations for using MMR vaccine in children allergic to eggs
Children with egg allergy can safely be given the measles, mumps and rubella (MMR) vaccine, shows a review of the available evidence in this week's BMJ. The MMR vaccine is grown in cultures from chick cells, and there have been concerns that the vaccine could trigger a dangerous reaction in children who are allergic to eggs.
Khakoo and Lack, from the Department of Paediatric Allergy and Immunology at St Mary's Hospital, London, show that most of the reported life threatening allergic reactions to the MMR vaccine have been in children who were not allergic to eggs. Egg allergy is not always tested for correctly, they say, and the data from properly conducted food allergy tests show that the amount of egg needed to provoke a reaction is at least 100,000 times more than is found in any dose of the vaccine. Using annual data on live births and a 1 per cent rate of allergy to eggs in early childhood, the authors calculate that almost 6,000 MMR vaccinations in England and Wales are given to 1 to 2 year old children with egg allergies with no adverse effects.
The authors argue that the main culprits in children who have reacted to the MMR vaccine might be gelatin and the antibiotic neomycin, both of which are found in much larger quantities than egg cells, and which are known to cause allergic reactions. Only children with a known egg allergy who have had a life-threatening reaction or who have egg allergy and chronic severe asthma may be at risk of adverse effects from MMR vaccination. These children should be vaccinated in hospital, but they represent a tiny minority of children with egg allergy, say the authors. "The MMR vaccine is as safe as any other vaccine, and children with an allergy to eggs must not have their vaccinations delayed," they conclude. Their recommendations have been endorsed by a specialist committee of the Royal College of Paediatrics and Child Health and the British Society of Allergy and Clinical Immunology.
Contact:
Dr Gideon Lack, Department of Paediatric Allergy and Immunology, St Mary's Hospital, London