title: Seroprevalence of varicella in the French population.
abstract: OBJECTIVE
  To assess the age-specific seroprevalence of varicella in the French population and to explore age-adjusted differences according to gender and geographic region.
  
  
  METHODS
  Data were obtained from 1257 randomly selected, frozen serum samples, from subjects 1-30 years of age, that were sent to the Pasteur-Cerba laboratory in November 2003 to January 2004 for the following clinical indications: allergies, respiratory infections, herpes virus infections excluding varicella and endocrinologic tests. IgG concentrations were tested with an indirect enzyme immunoassay. Statistical analyses included use of locally weighted, scatterplot smoothers.
  
  
  RESULTS
  Age-specific seroprevalence of varicella increased by >6-fold between 1 and 8 years of age, ie, from 15.0% (95% confidence interval, 8.6-23.5%) for subjects 1-2 years of age to 89.0% (95% confidence interval, 81.0-94.3%) for those 7-8 years of age. The smoothed curve of age-specific seroprevalence suggested that the steepest rate of increase occurred between 1 and 8 years of age, followed by a considerable slowing in the rate of increase, reaching a prevalence of approximately 95% by age 30. Varicella seroprevalence rates were similar for the samples referred for the 4 clinical indications, as follows: allergies, 76.2%; respiratory infections, 74.0%; herpes virus infections excluding varicella, 73.3%; endocrinologic tests, 73.7% (P = 0.84).
  
  
  CONCLUSIONS
  Most varicella-zoster virus infections occur during early childhood. Seroprevalence rates reach approximately 50% by 4 years of age and approximately 90% by 8 years. Therefore, the best strategy to reduce the prevalence of wild-type varicella-zoster virus in the French population would be to immunize children 12-18 months of age, as is currently performed in the United States.
authors.affiliation: Cemka-Eval, Bourg La Reine, France.
authors.forename: Babak
authors.initials: B
authors.lastname: Khoshnood
authors.forename: Monique
authors.initials: M
authors.lastname: Debruyne
authors.forename: Florian
authors.initials: F
authors.lastname: Lançon
authors.forename: Corinne
authors.initials: C
authors.lastname: Emery
authors.forename: Francis
authors.initials: F
authors.lastname: Fagnani
authors.forename: Isabelle
authors.initials: I
authors.lastname: Durand
authors.forename: Daniel
authors.initials: D
authors.lastname: Floret
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000914:Antibodies, Viral / Q000097:blood; D002644:Chickenpox / Q000453:epidemiology*; D002648:Child; D002675:Child, Preschool; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005602:France / Q000453:epidemiology; D014645:Herpesvirus 3, Human / Q000276:immunology*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D016036:Seroepidemiologic Studies
chemical_list: D000914:Antibodies, Viral