title: [Incidence and risk factors for hepatitis A in the province of Guadalajara (Spain)].
abstract: BACKGROUND
  The decrease in the prevalence of hepatitis A in Spain may modify the characteristics of this infection because of the rise in the susceptible adult population. The aim of this study was to determine the incidence of this disease, as well as the epidemiological characteristics and the complications of patients diagnosed in the province of Guadalajara between 1991 and 1999.
  
  
  METHODS
  The inclusion criterion was the presence of specific IgM together with an increase in alanine aminotransferase concentrations and/or symptoms compatible with acute hepatitis.
  
  
  RESULTS
  The mean incidence was 7.13 cases/105 inhabitants. Considerable differences were found between years due to the presence of an outbreak. Most cases occurred in children and young adults. The most frequent risk factor found overall was contact with an infected individual but the distribution of risk factors differed between children and adults.
  
  
  CONCLUSIONS
  The decrease in the prevalence of hepatitis A in Spain entails an increase in the susceptible adult population. Consequently, hepatitis A may cease to be a typically pediatric disease and may become one that also affects young adults in whom it may have different characteristics. This consideration should be borne in mind when designing a vaccination strategy.
authors.affiliation: Sección de Microbiología, Hospital General de Guadalajara, Spain.
authors.forename: A
authors.initials: A
authors.lastname: González Praetorius
authors.forename: C
authors.initials: C
authors.lastname: Rodríguez-Avial
authors.forename: C
authors.initials: C
authors.lastname: Fernández
authors.forename: M T
authors.initials: MT
authors.lastname: Pérez Pomata
authors.forename: C
authors.initials: C
authors.lastname: Gimeno
authors.forename: J
authors.initials: J
authors.lastname: Bisquert
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D005260:Female; D006506:Hepatitis A / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D008297:Male; D008800:Mexico / Q000453:epidemiology; D008875:Middle Aged; D012307:Risk Factors