title: Response to challenge dose among young adults vaccinated for hepatitis B as infants: importance of detectable residual antibody to hepatitis B surface antigen.
abstract: OBJECTIVE
  To determine whether a difference in antibody to hepatitis B surface antigen (anti-HBs) response to a hepatitis B vaccine challenge dose existed among persons with a baseline anti-HBs level of 0 mIU/mL (group 1) and those with "non-zero" levels of 0.1-4.9 (group 2) and 5.0-9.9 (group 3) mIU/mL, according to the VITROS ECi anti-HBs assay.
  
  
  METHODS
  Subanalysis of randomized clinical trial. Response was defined as a postchallenge anti-HBs level of at least 10 mIU/mL and 4-fold rise in anti-HBs level 2 weeks after a single challenge dose of 10 vs 20 µg Engerix-B. Baseline was defined as the anti-HBs level immediately before administration of the challenge dose.
  
  
  METHODS
  Pediatric integrated healthcare system near Houston, Texas.
  
  
  METHODS
  Three hundred nineteen US-born 16-19-year-olds who completed the hepatitis B vaccine series during the first year of life.
  
  
  RESULTS
  One hundred seventy-eight persons had zero (group 1) and 141 (114 group 2 and 27 group 3) had non-zero anti-HBs levels at baseline. Response to the challenge dose was significantly higher among those with non-zero vs zero anti-HBs levels, irrespective of challenge dosage; only 1 person with a non-zero anti-HBs level failed to respond to the challenge dose (group 3, 27/27 [100%] vs group 2, 113/114 [99%] vs group 1, 145/178 [82%]; P<.0001).
  
  
  CONCLUSIONS
  Among participants with residual anti-HBs levels less than 10 mIU/mL 16-19 years after primary hepatitis B vaccination during infancy, non-zero anti-HBs levels, with rare exception, indicated persistence of immune memory to HBsAg.
  
  
  BACKGROUND
  ClinicalTrials.gov Identifier: NCT01341275
authors: 1Division of Viral Hepatitis,Centers for Disease Control and Prevention,Atlanta,Georgia.
authors: Philip R
authors: PR
authors: Spradling
authors: 1Division of Viral Hepatitis,Centers for Disease Control and Prevention,Atlanta,Georgia.
authors: Saleem
authors: S
authors: Kamili
authors: 1Division of Viral Hepatitis,Centers for Disease Control and Prevention,Atlanta,Georgia.
authors: Jian
authors: J
authors: Xing
authors: 1Division of Viral Hepatitis,Centers for Disease Control and Prevention,Atlanta,Georgia.
authors: Jan
authors: J
authors: Drobeniuc
authors: 1Division of Viral Hepatitis,Centers for Disease Control and Prevention,Atlanta,Georgia.
authors: Dale J
authors: DJ
authors: Hu
authors: 2Baylor College of Medicine,Houston,Texas.
authors: Amy B
authors: AB
authors: Middleman
mesh_terms: D000293:Adolescent; D005260:Female; D006509:Hepatitis B / Q000276:immunology / Q000517:prevention & control*; D006514:Hepatitis B Surface Antigens / Q000097:blood / Q000276:immunology*; D017325:Hepatitis B Vaccines / Q000276:immunology / Q000627:therapeutic use*; D006801:Humans; D007156:Immunologic Memory / Q000276:immunology; D007223:Infant; D008297:Male; D055815:Young Adult
chemical_list: D006514:Hepatitis B Surface Antigens; D017325:Hepatitis B Vaccines