It is known that there is a controversy in the literature about the safety of measles vaccine in children with IgE-mediated egg allergy, since the virus vaccine is grown in chicken fibroblast cell cultures, even though egg proteins could not be found.
Allergic reactions have, however, been observed in children without egg allergy. To ascertain whether MI does induce allergic reactions in egg allergic children, we have investigated 80 children (52 males and 28 females), median age 2 years 5 months, with a positive challenge test to egg and a positive skin test and/or RAST to egg. Prick tests to ovalbumin, checked after 20 minutes, were positive in 65 children (81%). Specific IgE (Phadebas, RAST, Pharmacia, Uppsala) to egg, judged positive if higher than 0.35 Ul/ml, was present in 67 children (83 %). To confirm egg allergy, an open challenge test was done under observation and with emergency equipment at hand. Reactions were defined as immediate if the first symptoms occurred within 4 hr of egg ingestion and delayed if these occurred after 4 hr. After the challenge test, 52 children (65%) showed immediate allergic reactions; asthma and/or oculorhinitis and/or rash in 25 (31 %), angioedema and urticaria in 27 (34%); 28 (35%) worsening of atopic dermatitis. These 80 children received subcutaneously 0.5 ml of Morbilvax vaccine (Sclavo, grown in chicken fibroblast cell cultures) and were checked within 4 hr for any immediate allergic reactions. In addition, the parents recorded possible reactions such as fever or rash at home. No allergic reactions were noted after MI. The usual reactions to vaccine, including fever and attenuated rash, were recorded in 14 (17%); fever in 10; attenuated rash in 3; attenuated rash and fever in 1. We conclude that MI seems to be safe even in children with documented egg allergy.