title: [Comparison of two different vaccination schemes against Hepatitis A and B in Mexican children and adolescents].
abstract: BACKGROUND
  Development of multiple antigens in combined vaccines offers the advantages of reducing costs, increasing compliance and provides dual protection. Hepatitis A is an endemic disease in Mexico and hepatitis B, notwithstanding low prevalence, confers risk of progression to cirrhosis, hepatocellular carcinoma, and high medical costs in consequence.
  
  
  OBJECTIVE
  Determine immunogenicity and reactogenicity of a combined vaccine when compared with use of conventional vaccines simultaneously.
  
  
  METHODS
  The present study was a prospective, open, and randomized trial; 73 healthy children and adolescents were included, all with negative serologic markers. They were assigned to one of the following groups: Group 1, combined vaccine (n = 49) Twinrix (HAV 720 UE/HBV 20 micrograms), and group 2, separate vaccines (n = 24) Engerix B 20 micrograms/Havrix 720 UE. Both groups were given two-dose series at months 0 and 6. Geometric titles of antibody production (GMT) anti-HAV and anti-HBV were determined in months 1, 2, 6 and 7. Adverse reactions were registered during the study.
  
  
  RESULTS
  No difference was observed between the two groups in age or gender. Immunogenicity anti-HAV: 100% of vaccines in both groups reached seroprotective levels (> or = 33 mUI/mL). Antibody titles in group 1 were three times higher than those in group 2 (9,696 mIU/mL vs. 3,940 mIU/mL [p = 0.003]) at the end of the study. Immunogenicity anti-HBV: All subjects in both groups reached seroprotective levels (> or = 10 mIU/mL) with similar antibody titles at the end of the study (group 1: 5,603 mIU/mL vs. group 2: 5,201 mIU/mL [p = 0.55 NS]). Reactogenicity: No serious adverse reactions were observed; main were local, and frequency and characteristics were similar in both groups.
  
  
  CONCLUSIONS
  Seroprotective levels and reactogenicity obtained from use of a combined vaccine against hepatitis A/B are acceptable when compared with use of conventional vaccines administered separately.
authors.affiliation: Departamento de Gastroenterología, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México, D.F. México. saraigh69@yahoo.com
authors.forename: Ma Saraí
authors.initials: MS
authors.lastname: González-Huezo
authors.forename: Francisco
authors.initials: F
authors.lastname: Sánchez-Avila
authors.forename: Marcelino
authors.initials: M
authors.lastname: García Mayol
authors.forename: Graciela
authors.initials: G
authors.lastname: Castro Narro
authors.forename: Sara
authors.initials: S
authors.lastname: Sixtos
authors.forename: Mauricio
authors.initials: M
authors.lastname: Lisker-Melman
authors.forename: David
authors.initials: D
authors.lastname: Kershenobich
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D006506:Hepatitis A / Q000276:immunology / Q000517:prevention & control*; D035922:Hepatitis A Antibodies / Q000097:blood; D022362:Hepatitis A Vaccines / Q000008:administration & dosage* / Q000276:immunology; D006509:Hepatitis B / Q000276:immunology / Q000517:prevention & control*; D006510:Hepatitis B Antibodies / Q000097:blood; D017325:Hepatitis B Vaccines / Q000008:administration & dosage* / Q000276:immunology; D006801:Humans; D007115:Immunization Schedule; D008297:Male; D008800:Mexico; D011446:Prospective Studies; D016896:Treatment Outcome; D017778:Vaccines, Combined / Q000008:administration & dosage / Q000276:immunology
chemical_list: D035922:Hepatitis A Antibodies; D022362:Hepatitis A Vaccines; D006510:Hepatitis B Antibodies; D017325:Hepatitis B Vaccines; D017778:Vaccines, Combined