Allergenic and Anaphylactogenic Properties of Vaccines Prepared from Embryonic Tissues of Developing Chicks

Abstract

Summary: Only one of 180 normal adults skin-tested with typhus-vaccines, egg-white or egg-yolk showed evidence of skin-sensitivity to the three antigens. This individual when subsequently inoculated subcutaneously with typhus-vaccine developed no systemic reaction. Of 150 adults receiving three subcutaneous doses of typhus-vaccine, four individuals developed skin-sensitivity to the whole typhus-vaccine alone, four to both egg-yolk and typhus-vaccine, one to both egg-yolk and egg-white and one to egg-yolk, egg-white and typhus-vaccine. None of these subjects developed a general reaction when subsequently inoculated with typhus-vaccine. In spite of the fact that many millions of soldiers have received egg-embryo vaccines, the number of severe reactions known to have occurred following their use has been minimal. Some severe reactions have occurred however when vaccines were administered to egg-sensitive individuals. The risk is probably greater in children, in which group more egg-sensitive individuals may be encountered. It is considered advisable therefore to be cautious in the administration of egg-vaccines to allergic or egg-sensitive individuals. The use of concentrated washed rickettsial suspensions which are relatively free of egg-antigens could be used as vaccine in these cases.