[Immunological effects of live attenuated hepatitis A vaccine].

11,451 health persons were inoculated with live attenuated hepatitis A vaccine (H2 strain) in 3 batches. Among them, 785 were tested for anti-HAV antibody response by ELISA. The results showed that H2-strain vaccine got a quick antibody response (2-5 weeks) and a high seroconversion rate (92.9%). Also, the titers of antibodies to HAV ranged from 1:2 to 1:32. The seroconversion of the first 12 recipients lasted for 3 years. The primary epidemiological studies demonstrated that H2-strain vaccine was effective in preventing hepatitis A. The relation between the positive rate of antibody and different dosage showed that 10(6.5)TCID50 could get a highest seroconversion rate (100%).