title: [Immunogenicity and long-term persistence of anti-HAV in groups with different attenuated and inactived hepatitis A vaccine dosage].
abstract: 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.
authors.affiliation: Department of Epidemiology, Medical Centre of Fudan University, Shanghai 200032, China.
authors.forename: X
authors.initials: X
authors.lastname: Wang
authors.forename: J
authors.initials: J
authors.lastname: Ma
authors.forename: Y
authors.initials: Y
authors.lastname: Zhang
mesh_terms: 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
chemical_list: D035922:Hepatitis A Antibodies; D022362:Hepatitis A Vaccines; D015164:Vaccines, Inactivated