title: Single-dose Universal Hepatitis A Immunization in One-year-old Children in Argentina: High Prevalence of Protective Antibodies up to 9 Years After Vaccination.
abstract: Single-dose hepatitis A virus (HAV) vaccination was implemented in all Argentinean children 12 months of age in 2005. Previous studies demonstrated high prevalence of protective antibody response 4 years after single-dose vaccination. This study assessed long-term seroprotection against HAV after vaccination.
  
  
  
  Children who received 1 dose of HAV vaccine at 1 year of age at least 6 years before enrollment were included at 5 centers in Argentina between 2013 and 2014. Demographic and socioeconomic characteristics were collected through a questionnaire. Blood samples were tested for anti-HAV antibodies. Antibody values ≥10 mIU/mL were considered seroprotective. Logistic regression analysis was performed to evaluate the association between demographic and socioeconomic variables and seroprotection.
  
  
  
  A total of 1088 children were included, with a median postvaccination interval of 7.7 years (range 6.3-9.2 years). Of these children, 97.4% (95% confidence interval: 96.3%-98.3%) had protective antibodies against HAV. No association between demographic or socioeconomic variables and seroprotection was found. Geometric mean concentration of antibody levels against HAV was 170.5 mUI/mL (95% confidence interval: 163.2-178.2 mUI/mL).
  
  
  
  Single-dose universal hepatitis A immunization in 1-year-old children resulted in sustained immunologic protection for up to 9 years in Argentina. These findings, along with the low current disease burden, confirm the success of the intervention.
authors.affiliation: From the *Dirección Nacional de Control de Enfermedades Inmunoprevenibles, Ministerio de Salud de la Nación, C.A.B.A., Argentina; †Laboratorio Nacional de Referencia de Hepatitis Virales, INEI-ANLIS "Dr. Carlos Malbrán", C.A.B.A., Argentina; ‡Dirección de Epidemiología del Ministerio de Salud Pública de la Provincia de Tucumán, Tucumán, Argentina; §Servicio de Gastroenterología. Hospital del Niño Jesús de Tucumán, Tucumán, Argentina; ¶Programa Ampliado de Inmunizaciones, Ministerio de Salud de la Provincia de Santa Fe, Santa Fe, Argentina; ‖Servicio de Gastroenterología, Hospital de Niños Dr. Orlando Alassia, Santa Fe, Argentina; **Hospital Nacional Prof. Dr. Alejandro Posadas, Provincia de Buenos Aires, Argentina; ††Hospital de Niños de San Justo, Provincia de Buenos Aires, Argentina; ‡‡Hospital de Niños Ricardo Gutiérrez, C.A.B.A. Argentina; and §§Comisión Nacional de Hepatología, Sociedad Argentina de pediatría, C.A.B.A., Argentina.
authors.forename: Analía
authors.initials: A
authors.lastname: Urueña
authors.forename: Jorge E
authors.initials: JE
authors.lastname: González
authors.forename: Analía
authors.initials: A
authors.lastname: Rearte
authors.forename: María E
authors.initials: ME
authors.lastname: Pérez Carrega
authors.forename: Rogelio
authors.initials: R
authors.lastname: Calli
authors.forename: María F
authors.initials: MF
authors.lastname: Pagani
authors.forename: Andrea
authors.initials: A
authors.lastname: Uboldi
authors.forename: Rosalía
authors.initials: R
authors.lastname: Vicentín
authors.forename: Patricia
authors.initials: P
authors.lastname: Caglio
authors.forename: María C
authors.initials: MC
authors.lastname: Cañero-Velasco
authors.forename: Angela
authors.initials: A
authors.lastname: Gentile
authors.forename: Margarita
authors.initials: M
authors.lastname: Ramonet
authors.forename: Carla
authors.initials: C
authors.lastname: Vizzotti
mesh_terms: D001118:Argentina; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006506:Hepatitis A / Q000517:prevention & control*; D035922:Hepatitis A Antibodies / Q000097:blood*; D022362:Hepatitis A Vaccines / Q000008:administration & dosage / Q000276:immunology*; D030041:Hepatitis A virus / Q000276:immunology*; D006801:Humans; D007223:Infant; D008297:Male; D015995:Prevalence
chemical_list: D035922:Hepatitis A Antibodies; D022362:Hepatitis A Vaccines