Successful immunization of children with and without maternal antibody by aerosolized measles vaccine. I. Different results with undiluted human diploid cell and chick embryo fibroblast vaccines.

Inhalation of undiluted, aerosolized measles vaccine was immunogenic in 100% of 4- to 6-month-old and older children with and without residual maternal antibody when the human diploid cell (HDC) vaccine containing the Ikić (Edmonston-Zagreb) strain and 1% human albumin was used but in a smaller percentage of infants given a chick embryo fibroblast (CEF) vaccine, which contained the Edmonston-Schwarz strain, ten times more virus, and hypertonic sugar solution but no added protein. Prevaccination residual placentally transmitted plaque-neutralizing antibody titers of 25 to 512 that can prevent an immune response after subcutaneous injection of measles vaccine did not prevent an immune response after inhalation of aerosolized vaccine. There were no immediate clinical reactions in the 160 children who inhaled the aerosolized vaccines, and no significant subsequent reactions among the 96 children who were successfully immunized. There were no contact infections.