1968 年 18 巻 3 号 p. 205-213
The virulent Towata strain of mumps virus was successfully passaged in the chorio allantoic cavity of developing chick embryos, and it was noticed that Towata strain was considerably attenuated after many passages (described in the first report). Attenuated Towata strain of various passage numbers was used in 4 field trials for children in 1967 by the inhalation method. Similar degree of antibody response was obtained in each trial, without any clinical manifestations due to the vaccination. Increase in NT antibody titer was 8 to 18 fold, and 80 per cent of seroconversion was observed in sero-negative cases. The rate of sero conversion of NT antibody was higher than that of HI antibody in paired sera. It was noticed that many children who had low antibody also showed antibody response. In inhalation trials with Enders strain adapted to the chorio allantoic cavity, antibody response almost similar to that of Towata strain was obtained.