title: Effect of aluminum hydroxide adjuvant on the immunogenicity of the 2009 pandemic influenza A/H1N1 vaccine: multi-level modeling of data with repeated measures.
abstract: OBJECTIVE
  To evaluate the effect of the aluminum hydroxide (Al-OH) adjuvant on the 2009 pandemic influenza A/H1N1 (pH1N1) vaccine.
  
  
  METHODS
  In a multicenter, double-blind, randomized, placebo-controlled trial, participants received two doses of split-virion formulation containing 15 μg hemagglutinin antigen, with or without aluminum hydroxide (Al-OH). We classified the participants into six age categories (>61 years, 41-60 years, 19-40 years, 13-18 years, 8-12 years, and 3-7 years) and obtained four blood samples from each participant on days 0, 21, 35, and 42 following the first dose of immunization. We assessed vaccine immunogenicity by measuring the geometric mean titer (GMT) of hemagglutination inhibiting antibody. We used a two-level model to evaluate the fixed effect of aluminum Al-OH and other factors, accounting for repeated measures.
  
  
  RESULTS
  The predictions of repeated measurement on GMTs of formulations with or without Al-OH, were 80.35 and 112.72, respectively. Al-OH significantly reduced immunogenicity after controlling for time post immunization, age-group and gender.
  
  
  CONCLUSIONS
  The Al-OH adjuvant does not increase but actually reduces the immunogenicity of the split-virion pH1N1 vaccine.
authors.affiliation: Chinese Center for Disease Control and Prevention, Beijing 100050, China.
authors.forename: Da Peng
authors.initials: DP
authors.lastname: Yin
authors.forename: Bao Ping
authors.initials: BP
authors.lastname: Zhu
authors.forename: Hua Qing
authors.initials: HQ
authors.lastname: Wang
authors.forename: Lei
authors.initials: L
authors.lastname: Cao
authors.forename: Wen Di
authors.initials: WD
authors.lastname: Wu
authors.forename: Ke Yu
authors.initials: KY
authors.lastname: Jiang
authors.forename: Wei
authors.initials: W
authors.lastname: Xia
authors.forename: Guo Min
authors.initials: GM
authors.lastname: Zhang
authors.forename: Jing Shan
authors.initials: JS
authors.lastname: Zheng
authors.forename: Ling Sheng
authors.initials: LS
authors.lastname: Cao
authors.forename: Xiao Feng
authors.initials: XF
authors.lastname: Liang
mesh_terms: D000277:Adjuvants, Pharmaceutic / Q000737:chemistry*; D000293:Adolescent; D000328:Adult; D000536:Aluminum Hydroxide / Q000737:chemistry*; D000914:Antibodies, Viral / Q000097:blood; D002648:Child; D002675:Child, Preschool; D002681:China; D003627:Data Interpretation, Statistical; D004311:Double-Blind Method; D005260:Female; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology*; D007252:Influenza Vaccines / Q000009:adverse effects / Q000737:chemistry / Q000276:immunology*; D007251:Influenza, Human / Q000453:epidemiology / Q000276:immunology / Q000517:prevention & control / Q000821:virology*; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D058873:Pandemics; D055815:Young Adult
chemical_list: D000277:Adjuvants, Pharmaceutic; D000914:Antibodies, Viral; D007252:Influenza Vaccines; D000536:Aluminum Hydroxide