Standardization of live, attenuated measles vaccine will be influenced by the relationship between the amount of virus administered and host response as well as by stability of the commercial product. Optimal dosage of virus may be defined as the number of infective units producing maximal immune response and minimal overt reactivity. In an effort to measure sensitivity of the human host to parenterally inoculated measles virus vaccine and to assess the effect of varying dosage on reaction rate and immunogenicity, titration of 2 measles vaccines in susceptible children was carried out. In addition, sensitivity of the respiratory tract has been measured indirectly. These data will be presented in the following report.
Children proven by serologic tests to be susceptible to measles were given 1.0 ml. quantities of serial 10-fold dilutions of measles vaccine prepared in medium 199 immediately prior to inoculation. The canine renal and chick embryo cell