Immunization of Humans with A Chick Embryo Adapted Strain of Mef1 Poliomyelitis Virus

Summary Antibodies for Type 2 poliomyelitis virus developed in 5 of 6 human subjects fed a strain of chick embryo adapted virus alone, and in 9 of 12 individuals who were fed the same virus followed by the injection of immune serum globulin. Although the number of persons in this trial was not large, certain important results may be summarized: 1) No adverse clinical reactions occurred in any subject. 2) Viremia did not appear. 3) Specific antibodies were produced in 14 of 18 subjects. 4) Antibodies persisted for periods up to 8 months. 5) Only three of the 18 individuals excreted virus, after the 4th postfeeding day, and that was of low concentration. 6) The virus proved to be stable, since after human passage it was found to (a) retain its chick embryo adaptation characteristics, b) possess low cytopathogenic activity for monkey kidney cells in tissue culture, and c) to have low pathogenicity for monkeys inoculated intracerebrally.