[The trial preparation of attenuated live hepatitis A vaccine].

The experimental attenuated live hepatitis A vaccine has been prepared in KMB17 human fetal lung diploid cells with the HAV variant H2M20K5 (32 degrees C). No extraneous agent was detected in the vaccine, which had a titer of 10(6.5) TCID50/ml. Twelve monkeys vaccinated intravenously or subcutaneously were found to have no significant clinical hepatitis but with anti-HAV antibody in all cases. Thus the safety and immunogenicity of the vaccine were evidenced in monkeys and it is necessary to investigate the trial vaccination further in a few susceptible individuals.