[Further survey on efficacy of attenuated live hepatitis A vaccines].
OBJECTIVE
To further survey the protective efficacy of the standard attenuated live hepatitis A vaccines (H(2) strain).


METHODS
Randomized and controlled trials were performed in Fucheng county, Hebei province. A total of 12 036 children were assigned into vaccine group (5 551) and control group (6 485) by cluster sampling. The morbidity of hepatitis A was observed and the blood was collected once hepatitis A showed epidemic to detect anti-HAV IgG and IgM.


RESULTS
During the period of the first 7 months after vaccination, hepatitis A was sporadic, the morbidity of hepatitis A was 0.55/100 000, and only 1 case occurred in the control group and no case in the vaccine group. From January to August 1998, hepatitis A showed epidemic in a township of this county. The morbidities were 0.37% and 6.69% for vaccine group and control group, respectively. The protective efficacy of the vaccine was 94.47%. The ratios of clinical cases to subclinical infections were 1 to 11 and 1 to 1 for vaccine and control groups, respectively (P < 0.05).


CONCLUSIONS
The H(2) strain vaccine has a very good protective efficacy, and obviously decreases the attack rate, new infection rate and clinical cases by HAV infection.
Meng
Z
Z
Hebei Province Sanitary and Anti-epidemic Station, Baoding 071000, China.
Yao
J
J
Zhao
Y
Y
D002648:Child; D002681:China / Q000453:epidemiology; D005260:Female; D006506:Hepatitis A / Q000453:epidemiology / Q000517:prevention & control*; D022362:Hepatitis A Vaccines / Q000276:immunology*; D006801:Humans; D008297:Male; D014613:Vaccines, Attenuated / Q000276:immunology
D022362:Hepatitis A Vaccines; D014613:Vaccines, Attenuated