[MMR vaccine and allergy] 2000; 82:93-7
Children who are allergic to eggs do not seem to be at greater risk of a severe allergic reaction to the measles, mumps and rubella (MMR) vaccine. Writing in Archives of Disease in Childhood, Drs Raman Lakshman and Adam Finn, from the University of Sheffield’s Institute of Vaccine Studies, say that the severe reaction, known as anaphylaxis, although potentially fatal, is extremely rare. It could happen after any vaccination and is not exclusive to MMR.
MMR vaccine contains live measles virus, which is cultured in chick embryo cells. As such, the vaccine may contain minute amounts of egg related antigens - substances that act as a trigger for those who are sensitised to the source matter, in this case, eggs. There has been a longstanding debate on the safety of the MMR vaccine for children with egg allergy.
But say the authors, there is a growing body of evidence to suggest that there is no significant danger: of 40 cases of anaphylaxis to MMR reported by 1995, just two involved children with egg allergy. A further trial of 410 children with egg allergy showed that only five tested positive for the allergy when quantities of the vaccine were put on the skin, but none of whom reacted when vaccinated. While four who did not test positive, had a mild reaction to being vaccinated.
The Department of Health currently advises that where there is concern about egg allergy, extra precautions should be considered. Such children are "regularly referred for specialist advice and day case admission for immunisation in our centre, and we believe, in most others - a significant use of time and resources," comment the authors.
The culprit in allergic reactions to MMR may very well be gelatin, say the authors, citing several studies from Japan, where allergic reactions to MMR have recently increased, although they point out that there is no evidence to suggest a similar increase in the UK. "Most severe reactions [to vaccines in general]occur within a few minutes after the injection, and it is extremely unlikely that a child who appears completely well 30 minutes after the vaccination will subsequently develop a severe reaction," conclude the authors.
Contact: Dr Adam Finn, Sheffield Institute for Vaccine Studies, University of Sheffield. a.finn@shef.ac.uk
Journal
Archives of Disease in Childhood