title: Seroprevalence of hepatitis B in two period birth cohorts of Bolivian children: effect of universal vaccination.
abstract: BACKGROUND
  Since 2000 universal routine immunization against the hepatitis B virus (HBV) was implemented in Bolivia. This study aimed to assess the seroprevalence of markers against HBV in two different birth cohorts (pre-universal vaccine cohort and post-universal vaccine cohort) from Cochabamba, Bolivia.
  
  
  METHODS
  We performed a school-based seroepidemiological survey (n = 424) of HBV in 2010 in the Cochabamba region. An ELISA test was used to measure antibodies to the hepatitis B surface antigen (anti-HBs IgG) and to the hepatitis B core antigen (anti-HBc IgG).
  
  
  RESULTS
  The prevalence of anti-HBs IgG in the pre-universal vaccine cohort was 5.8% (95% CI: 3.3-8.3%); it was higher in boys (9.1%), and those living in suburbs (9.7%). The anti-HBs IgG prevalence among post-universal vaccine cohort was 37.9% (95% CI: 28.5-48.1%), and was higher in children who spoke Quechua at home (51.0%), those living in suburbs (53.9%), and those born in 2005 (72.7%). Neither cohort showed differences relating to parental education. The prevalence of anti-HBc IgG was 1.1% among post-universal vaccine cohort and 1.2% among pre-universal vaccine cohort (p > 0.05).
  
  
  CONCLUSIONS
  This study identified a persistent low seroprevalence of hepatitis B infection in spite of a decade of universal immunization, and low long-term humoral immunity against HBV infection in vaccinated children in Cochabamba.
authors.affiliation: Bellvitge Biomedical Research Institute IDIBELL, International Health Centre and Travel Medicine Clinic, Preventive Medicine Department, University Hospital of Bellvitge, Catalonia, Spain. cmasuet@bellvitgehospital.cat
authors.forename: Cristina
authors.initials: C
authors.lastname: Masuet-Aumatell
authors.forename: Josep M
authors.initials: JM
authors.lastname: Ramon-Torrell
authors.forename: Aurora
authors.initials: A
authors.lastname: Casanova-Rituerto
authors.forename: Marta
authors.initials: M
authors.lastname: Banqué-Navarro
authors.forename: María Del Rosario
authors.initials: Mdel R
authors.lastname: Dávalos-Gamboa
authors.forename: Sandra Lucía Montaño
authors.initials: SL
authors.lastname: Rodríguez
mesh_terms: D000293:Adolescent; D000888:Antibodies, Anti-Idiotypic / Q000097:blood; D001838:Bolivia / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D006509:Hepatitis B / Q000453:epidemiology* / Q000276:immunology / Q000517:prevention & control; D006510:Hepatitis B Antibodies / Q000097:blood*; D017325:Hepatitis B Vaccines / Q000008:administration & dosage* / Q000276:immunology; D006801:Humans; D007117:Immunization, Secondary; D008297:Male; D016036:Seroepidemiologic Studies
chemical_list: D000888:Antibodies, Anti-Idiotypic; D006510:Hepatitis B Antibodies; D017325:Hepatitis B Vaccines; C048844:anti-IgG
keywords: Bolivia; Booster; Hepatitis B vaccine; Hepatitis B virus; Universal hepatitis B vaccination