title: A two-dose combined vaccine against hepatitis A and hepatitis B in healthy children and adolescents compared to the corresponding monovalent vaccines.
abstract: BACKGROUND
  Immunization against hepatitis A and B has been available for some time, protecting against both infections. With a view to achieving further reduction in the number of interventions and increasing convenience of the vaccinee, we investigated the reactogenicity and immunogenicity of a combined hepatitis A and B vaccine in healthy 4- to 20-year-old subjects at a 0, 6-month schedule.
  
  
  METHODS
  Two hundred forty-eight study subjects were allocated to two study groups and received either two doses of the combined hepatitis A and B vaccine (68% of subjects) or the corresponding monovalent hepatitis A and hepatitis B vaccines (32% of subjects) concomitantly in opposite arms. Reactogenicity was assessed via diary cards after each vaccination. Serum samples were analyzed at months 1, 2, 6, and 7.
  
  
  RESULTS
  All vaccines were well tolerated and very few symptoms were scored as severe. All but one subject seroconverted for anti-hepatitis A virus (anti-HAV) antibodies (98.6%) and 100% of subjects seroconverted for anti-hepatitis B (HBs) antibodies, with respective seroprotection rates of 98.7% for the combined vaccine group and 95.9% for the concomitant vaccine group (p >0.05), respectively. Geometric mean titers were higher in the group receiving the combined vaccine: 6,635 mIU/mL vs. 2,728 mIU/mL (p = 0.0001) for anti-HAV and 3,362 mIU/mL vs. 1,724 mIU/mL (p = 0.0205) for anti-HBs, respectively. Younger subjects had a stronger immune response compared to older subjects.
  
  
  CONCLUSIONS
  The combined hepatitis A and B vaccine was well tolerated at this two-dose schedule. The combined vaccine had higher immunogenicity, probably explained by a adjuvant effect of the antigens. Vaccination programs requiring fewer injections will most likely have a positive impact on compliance rate and comfort of the vaccinee.
authors.affiliation: Unidad de Gastroenterología Pediátrica, Hospital Nacional Alejandro Posadas Haedo, Buenos Aires, Argentina.
authors.forename: Margarita
authors.initials: M
authors.lastname: Ramonet
authors.forename: Themis Reverbel
authors.initials: TR
authors.lastname: da Silveira
authors.forename: Mauricio
authors.initials: M
authors.lastname: Lisker-Melman
authors.forename: Ricardo
authors.initials: R
authors.lastname: Rüttimann
authors.forename: Eduardo
authors.initials: E
authors.lastname: Pernambuco
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Cervantes
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Cañero-Velasco
authors.forename: Luiza Elena
authors.initials: LE
authors.lastname: Falleiros-Carvalho
authors.forename: Tania
authors.initials: T
authors.lastname: Azevedo
authors.forename: Cristina
authors.initials: C
authors.lastname: Targa-Ferreira
authors.forename: Sue Ann Costa
authors.initials: SA
authors.lastname: Clemens
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D006506:Hepatitis A / Q000517:prevention & control*; D035922:Hepatitis A Antibodies; D022362:Hepatitis A Vaccines / Q000008:administration & dosage*; D006508:Hepatitis Antibodies / Q000097:blood*; D006509:Hepatitis B / Q000517:prevention & control*; D006510:Hepatitis B Antibodies / Q000097:blood*; D017325:Hepatitis B Vaccines / Q000008:administration & dosage*; D006801:Humans; D007115:Immunization Schedule; D008297:Male; D017778:Vaccines, Combined / Q000008:administration & dosage
chemical_list: D035922:Hepatitis A Antibodies; D022362:Hepatitis A Vaccines; D006508:Hepatitis Antibodies; D006510:Hepatitis B Antibodies; D017325:Hepatitis B Vaccines; D017778:Vaccines, Combined