title: Hepatitis B vaccine administered to children and adolescents at yearly intervals.
abstract: OBJECTIVE
  Hepatitis B vaccines are usually administered on a schedule of 0, 1 to 2, and 6 months. Longer intervals between the second and third doses have been studied, but the effectiveness of hepatitis B vaccine administered at intervals of >2 months between the first and second doses have not been studied. Our objective was to compare the antibody response in recipients of Engerix-B hepatitis B vaccine administered at 12-month intervals to the response to vaccine administered at 0-, 1-, and 6-month intervals.
  
  
  METHODS
  A total of 389 children, 5 through 16 years of age, were randomized to receive Engerix-B (10 mg) at a schedule of either 0-, 1-, and 6-month intervals or 0-, 12-, and 24-month intervals. Blood was drawn before and 1 month after the third dose.
  
  
  RESULTS
  Immediately before the third dose of vaccine, 92.3% of children who received vaccine on the 0-, 1-, and 6-month schedule and 88.8% of children who received the 0-, 12-, and 24-month schedule had antibody to hepatitis B surface (anti-HBs) antigen concentrations >/=10 mIU/mL. Of the children in the 0-, 1-, and 6-month schedule, 95% received the third dose according to protocol versus 90% of those in the 0-, 12-, 24-month schedule. The geometric mean anti-HBs concentration just before the third dose for recipients of the 0-, 1-, and 6-month schedule (117.9 mIU/mL) was somewhat lower than that for the children who had received vaccine on the 0-, 12-, and 24-month schedule (162.1 mIU/mL). One month after the third dose, >98% of all children had anti-HBs concentrations >/=10 mIU/mL and high geometric mean antibody concentrations were observed in both groups: 5687 mIU/mL for children on the 0-, 1-, and 6-month schedule and 3159 mIU/mL for children on the 0-, 12-, and 24-month schedule. Body mass index was correlated inversely with final antibody concentration, but age was not a factor after adjustment for body mass index.
  
  
  CONCLUSIONS
  Engerix-B administered on a 0-, 12-, and 24-month schedule is highly immunogenic. Providers should consider this alternate immunization schedule for children who are at low risk of immediate exposure to hepatitis B infections.
authors.affiliation: Department of International Health, Johns Hopkins University School of Hygiene and Public Health, Baltimore, Maryland, USA. nhalsey@jhsph.edu
authors.forename: N A
authors.initials: NA
authors.lastname: Halsey
authors.forename: L H
authors.initials: LH
authors.lastname: Moulton
authors.forename: J C
authors.initials: JC
authors.lastname: O'Donovan
authors.forename: J R
authors.initials: JR
authors.lastname: Walcher
authors.forename: M L
authors.initials: ML
authors.lastname: Thoms
authors.forename: H S
authors.initials: HS
authors.lastname: Margolis
authors.forename: D S
authors.initials: DS
authors.lastname: Krause
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D015992:Body Mass Index; D002648:Child; D002669:Child Welfare; D002675:Child, Preschool; D002908:Chronic Disease; D005260:Female; D006509:Hepatitis B / Q000276:immunology* / Q000517:prevention & control*; D017325:Hepatitis B Vaccines / Q000008:administration & dosage*; D006801:Humans; D007115:Immunization Schedule; D008297:Male; D010507:Periodicity; D011446:Prospective Studies; D011795:Surveys and Questionnaires; D013997:Time Factors
chemical_list: D017325:Hepatitis B Vaccines