title: [Efficacy and immune memory of plasma-derived hepatitis B vaccine 11 years after primary immunization].
abstract: OBJECTIVE
  To evaluate the long-term efficacy of hepatitis B vaccine 10 years after primary immunization to provide scientific basis for the time of revaccination.
  
  
  METHODS
  The study was strictly designed with randomization, double-blinding, and placebo-controlled method to observe the efficacy and immune memory 11 years following hepatitis B vaccination.
  
  
  RESULTS
  Immunogenicity and protective rate of vaccine were still kept well 11 years after immunization with a protective rate against HBV infection of 73.5%. But, there was no significant difference in HBV infection rates between vaccine group and placebo-controlled group (7.89% vs. 13.25%, P > 0.1) nine to 11 years following immunization. There still existed immune memory 11 years after immunization, but it was significantly weaker than that within the first 10 years after immunization.
  
  
  CONCLUSIONS
  The efficacy of the vaccine had begun to drop 11 years after immunization, which should be followed up further to reach a clear conclusion.
authors.affiliation: Department of Epidemiology, Xi'an Medical University, Xi'an 710061, China.
authors.forename: H
authors.initials: H
authors.lastname: Xu
authors.forename: G
authors.initials: G
authors.lastname: Zhuang
authors.forename: X
authors.initials: X
authors.lastname: Wang
authors.forename: Q
authors.initials: Q
authors.lastname: Chen
authors.forename: Z
authors.initials: Z
authors.lastname: Chen
mesh_terms: D004311:Double-Blind Method; D005500:Follow-Up Studies; D006509:Hepatitis B / Q000517:prevention & control*; D006510:Hepatitis B Antibodies / Q000097:blood; D006512:Hepatitis B Core Antigens / Q000097:blood; D006514:Hepatitis B Surface Antigens / Q000097:blood; D017325:Hepatitis B Vaccines / Q000276:immunology*; D006801:Humans; D013997:Time Factors; D014611:Vaccination
chemical_list: D006510:Hepatitis B Antibodies; D006512:Hepatitis B Core Antigens; D006514:Hepatitis B Surface Antigens; D017325:Hepatitis B Vaccines