[Immunogenicity and efficacy trials of live attenuated hepatitis A vaccines].
OBJECTIVE
To study two live vaccines, H2 and LA-1 strains, both attenuated in growth on human diploid cell culture at lower temperature (32 degrees C).


METHODS
Randomized, controlled trials were performed among half million children. 135,340 children were divided into vaccine or control groups by individual and 360,012 by cluster. Those susceptibles with negative anti-HAV were bled at 2-6 months after the vaccination and blood test for anti-HAV.


RESULTS
37 hepatitis A cases were found in the control group. The protective efficacy of the two vaccines was 100%, and the 95% lower confidence limit (one sided) of combined efficacy of the two vaccines was 92.1%, that was comparable with the two inactivated vaccines produced by SmithKline beecham or Merck Sharp Dhome.


CONCLUSIONS
The vaccines are safe, and the seroconversion to H2 strain (10(7.0) TCID50) and LA-1 strain (10(6.75) TCID50) is 94.87% and 83.16% respectively.
Shanghai Medical University.
Z
Z
Xu
R
R
Li
Z
Z
Meng
D002648:Child; D002675:Child, Preschool; D005260:Female; D006506:Hepatitis A / Q000517:prevention & control*; D035922:Hepatitis A Antibodies; D022362:Hepatitis A Vaccines; D006508:Hepatitis Antibodies / Q000097:blood; D006801:Humans; D007223:Infant; D008297:Male; D014613:Vaccines, Attenuated / Q000276:immunology; D014761:Viral Hepatitis Vaccines / Q000276:immunology*
D035922:Hepatitis A Antibodies; D022362:Hepatitis A Vaccines; D006508:Hepatitis Antibodies; D014613:Vaccines, Attenuated; D014761:Viral Hepatitis Vaccines