Editor, In the article 'Testing for drug allergy' (Aust Prescr 1994;17:62-5) I believe the wrong impression is provided under recommendations concerning vaccines in egg sensitive patients in that it is stated 'small amounts of egg protein may be found in vaccines for influenza, measlesmumpsrubella and yellow fever'. In the subsequent recommendation concerning skin testing, no distinction is made between these vaccines. As influenza and yellow fever vaccine are grown in eggs, there may be small amounts of egg protein present and caution is required in egg sensitive individuals. In contrast, measlesmumpsrubella is produced on chicken fibroblasts and does not contain any egg protein. There have been suggestions of cross reacting proteins1; however, the likelihood of significant immediate hypersensitivity reaction in egg sensitive individuals is of a different order to that with vaccines grown in eggs. It is important to make the distinction between the two types of vaccine.
The requirement for skin prick testing and intra dermal testing with vaccine in egg sensitive children, prior to the administration of measles vaccine, has no firm scientific basis. We have demonstrated in a recent publication that a positive reaction on either intra dermal or prick tests with vaccine does not predict a significant adverse reaction to vaccination.2 We and other authorities1-4 have questioned the scientific validity of skin prick testing in egg sensitive children prior to administration of measles vaccine. It is important to distinguish between those vaccines which are grown in eggs and may be contaminated with egg protein and the measlesmumpsrubella vaccine when discussing the requirements for skin testing in egg sensitive subjects.
Andrew Kemp
Director of Clinical Immunology
Consultant Paediatrician
Royal Children's Hospital
Melbourne, Vic.
