title: Hepatitis B virus infection and vaccine-induced immunity in Madrid (Spain).
abstract: OBJECTIVE
  To estimate the prevalence of hepatitis B virus (HBV) infection and vaccine-induced immunity in the region of Madrid, and to analyze their evolution over time.
  
  
  METHODS
  An observational, analytical, cross-sectional study was carried out in the population aged 16-80 years between 2008 and 2009. This was the last of four seroprevalence surveys in the region of Madrid. The prevalence of HBV infection and vaccine-induced immunity was estimated using multivariate logistic models and were compared with the prevalences in the 1989, 1993 and 1999 surveys.
  
  
  RESULTS
  In the population aged 16-80 years, the prevalence of HBV infection was 11.0% (95% CI: 9.8-12.3) and that of chronic infection was 0.7% (95% CI: 0.5-1.1). The prevalence of vaccine-induced immunity in the population aged 16-20 years was 73.0% (95% CI: 70.0-76.0). Compared with previous surveys, there was a decrease in the prevalence of HBV infection.
  
  
  CONCLUSIONS
  Based on the prevalence of chronic infection (<1%), Madrid is a region with low HBV endemicity. Preventive strategies against HBV should especially target the immigrant population.
authors.affiliation: Subdirección General de Promoción de la Salud y Prevención, Dirección General de Atención Primaria, Madrid, Spain.
authors.forename: Ana María
authors.initials: AM
authors.lastname: Pedraza-Flechas
authors.affiliation: Subdirección General de Promoción de la Salud y Prevención, Dirección General de Atención Primaria, Madrid, Spain. Electronic address: luis.garcia@salud.madrid.org.
authors.forename: Luis
authors.initials: L
authors.lastname: García-Comas
authors.affiliation: Subdirección General de Promoción de la Salud y Prevención, Dirección General de Atención Primaria, Madrid, Spain.
authors.forename: María
authors.initials: M
authors.lastname: Ordobás-Gavín
authors.affiliation: Subdirección General de Ordenación, Dirección General de Ordenación e Inspección, Consejería de Sanidad, Madrid, Spain.
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Sanz-Moreno
authors.affiliation: Subdirección General de Ordenación, Dirección General de Ordenación e Inspección, Consejería de Sanidad, Madrid, Spain.
authors.forename: Belén
authors.initials: B
authors.lastname: Ramos-Blázquez
authors.affiliation: Subdirección General de Promoción de la Salud y Prevención, Dirección General de Atención Primaria, Madrid, Spain.
authors.forename: Jenaro
authors.initials: J
authors.lastname: Astray-Mochales
authors.affiliation: Ramón y Cajal Hospital, Madrid, Spain.
authors.forename: Santiago
authors.initials: S
authors.lastname: Moreno-Guillén
mesh_terms: D056704:Adaptive Immunity; D000293:Adolescent; D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D054242:Emigrants and Immigrants; D005260:Female; D006509:Hepatitis B / Q000453:epidemiology* / Q000517:prevention & control; D006510:Hepatitis B Antibodies / Q000032:analysis*; D017325:Hepatitis B Vaccines / Q000276:immunology*; D019694:Hepatitis B, Chronic / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D016036:Seroepidemiologic Studies; D014505:Urban Population; D014611:Vaccination / Q000706:statistics & numerical data; D055815:Young Adult
chemical_list: D006510:Hepatitis B Antibodies; D017325:Hepatitis B Vaccines
keywords: Chronic hepatitis B; Estudio Seroepidemiológico; Hepatitis B; Hepatitis B crónica; Hepatitis B vaccine; Immunization; Inmunización; Seroepidemiologic Study; Vacuna Hepatitis B