Skin reaction to yellow fever vaccine after immunization with rabies vaccine of chick embryo cell culture origin.

Skin reaction to yellow fever vaccine was examined after immunization with rabies vaccine. The two vaccines contained substrates from chick embryo cells (rabies vaccine) and chick whole embryo (yellow fever attenuated vaccine), as well as gelatin. A prick test with gelatin showed negative results in all vaccinees examined. An intradermal skin test revealed that the yellow fever vaccine had reacted with an anti-egg protein antibody-like substance in a case with a history of egg allergy before rabies vaccination. A case inoculated two times with the rabies vaccine revealed a positive reaction to egg-white protein as well as the yellow fever vaccine. This case had no anamnesis of egg allergy. Thus, an antibody reactive to the egg-white protein and/or the yellow fever vaccine was inducible by the rabies vaccine. The reaction of this antibody was not systemic but local at the skin test by the yellow fever vaccine. The period of the rabies vaccine sensitization reactive to the yellow fever vaccine could be estimated as longer than 14.3 +/- 9.6 days (mean +/- SD), based on a follow-up examination of the positive skin reaction in 41 of 84 cases examined. We therefore conclude that the yellow fever vaccine can be safely administered at an interval of at least four weeks after a second rabies vaccination.