A STUDY ON THE EFFICACY OF STANDARDIZED CHINA-MADE LIVE ATTENUATED HEPATITIS A VACCINE(H_2 STRAIN)

ObjectiveTo access the efficacy of China-made live attenuated hepatitis A vaccine (H 2 strain).Methods3 515 HAV susceptibles aged from 1～7 years old were randomized individually into vaccine and control group by birth month. Children in the vaccine group were given one dose of live attenuated hepatitis A vaccine while the children in the control group were given nothing. The attack rate in vaccine and control groups were followed up for 3.5 years after vaccination.ResultsIn the 3.5 years of following up, 14 hepatitis A cases were found in the control group and 1 case in control group. The attack rate in vaccine group and control group was 8.47 ‰ and 0.55 ‰ respectively. The difference of attack rate between the vaccine and control groups were significantly important and the efficacy of the vaccine was 93.51 %(95% lower confidence interval: 64.56 %).ConclusionThe efficacy of live attenuated hepatitis A vaccine (106.5TCID50/ml) was good and it can be used for mass immunization.