[Immunogenicity and long-term persistence of anti-HAV in groups with different attenuated and inactived hepatitis A vaccine dosage].
OBJECTIVE
This study was carried out to assess the long-term persistence of antibodies against hepatitis A in different vaccine dosage groups.


METHODS
One hundred and sixty-six susceptibles aged form 6 to 8 years old were selected in Zhengding county, and were divided into 4 different dose groups. Each group received 10(6.17)TCID(50), 10(6.52)TCID(50), 10(6.83)TCID(50) of attenuated hepatitis A vaccine or 10(6.83)TCID(50) of the same vaccine but treated with 60 degrees C for 3 hours. All subjects were bled at month 3, 12, 24, 36 and 48. All serum specimens were tested for antibodies to HAV using Abbott-IMx mEIA reagent. Part of the tested negative serum specimens were retested by neutralization assay for 10(6.52)TCID(50) and 10(6.83)TCID(50) dosage groups at 4 years after vaccination.


RESULTS
The seroconversion rate and GMT 3 months after vaccination in each dosage group showed a significant dose-response relationship. Antibody levels reached the peak at month 3 in each group but declined dramatically within one year and the decline slowed down thereafter. The serocoversion rate and GMT in 10(6.83)TCID(50) dose group 4 years after vaccination was significant higher than those of other dosage groups. Positive rates of neutralizing antibodies in B and C dosage group were 60.0% and 83.3% respectively.


CONCLUSIONS
The immunogenicity and long-term persistence were related to the attenuated hepatitis A vaccine titer. The vaccine, whose titer was 10(6.83)TCID(50), had good immunogenicity and long-term persistence. Booster dose was not needed within short time after initial vaccination.
Wang
X
X
Department of Epidemiology, Medical Centre of Fudan University, Shanghai 200032, China.
Ma
J
J
Zhang
Y
Y
D002648:Child; D004306:Dose-Response Relationship, Immunologic; D005260:Female; D035922:Hepatitis A Antibodies / Q000097:blood*; D022362:Hepatitis A Vaccines / Q000276:immunology*; D006801:Humans; D008297:Male; D015164:Vaccines, Inactivated / Q000276:immunology
D035922:Hepatitis A Antibodies; D022362:Hepatitis A Vaccines; D015164:Vaccines, Inactivated