[Studies on re-immunization with live attenuated hepatitis A vaccine].
OBJECTIVE
The possibility of re-immunization with a booster dose of live attenuated hepatitis A (HA) vaccine was studied.


METHODS
Children randomly sampled were divided into three groups with re-immunization, primary immunization and immunity via natural infection. Antibodies against hepatitis A virus (anti-HAV) were detected qualitatively and quantitatively with modified Abbott enzyme immunoassay (EIA).


RESULTS
Proportion of children with positive anti-HAV and its mean geometric titer (GMT) increased within two weeks after re-immunization, and as compared, those increased slowly and GMT reached the peak three months after primary immunization. Response to the live attenuated vaccine differed between the groups of re-immunization and immunity via natural infection, and should be taken into consideration in studying immune persistence of the vaccine. Proportion of children, who converted negative of their anti-HAV after primary immunization, with positive anti-HAV after re-immunization was 83.3% (10/12), significantly higher than that in those who failed in primary immunization and then were vaccinated again (50%, with 17/34), and that in both of them were higher than in primary immunization (29.6%).


CONCLUSIONS
Reminiscence could be induced by re-immunization, and the effects of it depended on primary immunization. Detection of anti-HAV with modified Abbott EIA still underestimated primary immune reaction. A more sensitive and specific method for detecting anti-HAV after vaccination should be used.
D002648:Child; D005260:Female; D006506:Hepatitis A / Q000517:prevention & control*; D022362:Hepatitis A Vaccines; D017957:Hepatitis A Virus, Human / Q000276:immunology; D006508:Hepatitis Antibodies / Q000097:blood; D006801:Humans; D007117:Immunization, Secondary; D008297:Male; D011897:Random Allocation; D014613:Vaccines, Attenuated; D014761:Viral Hepatitis Vaccines / Q000276:immunology*