title: The effectiveness of varicella vaccination in children in Germany: a case-control study.
abstract: BACKGROUND
  Effectiveness of 1 dose of varicella vaccination was estimated to be 85-88% against clinical varicella of any severity in case-control studies in non-European countries, but lower effectiveness has been demonstrated in outbreaks.
  
  
  METHODS
  A prospective, age- and practice-matched case-control study was conducted in Germany to assess the effectiveness of 1 dose of OKA/GSK varicella vaccine (derived from the OKA strain, a Japanese clinical isolate) and of any varicella vaccine (including OKA/GSK, OKA/Merck and MMR-OKA/GSK) against polymerase chain reaction (PCR)-confirmed varicella under conditions of routine use.
  
  
  RESULTS
  The cohort included 432 PCR-confirmed cases and 432 matched controls (1-7 years old). Varicella vaccination was reported for 13.2% (57/432) of cases and 45.1% (195/432) of controls. Median time since vaccination was 28 and 25 months, respectively. Vaccinated cases experienced milder disease (P < 0.0001) and shorter duration of disease (P = 0.004) compared with unvaccinated cases. After adjusting for gender and school/day-care attendance, vaccine effectiveness of 1 dose of OKA/GSK against PCR-confirmed varicella of any severity was 71.5% (95% confidence interval [CI]: 49.1-84.0) and 94.7% (95% CI: 77.8-98.7) against PCR-confirmed moderate or severe varicella. Adjusted effectiveness for any varicella vaccine was 86.4% (95% CI: 77.3-91.8) against any severity and 97.7% (95% CI: 90.5-99.4) against moderate or severe varicella.
  
  
  CONCLUSIONS
  One dose of varicella vaccine provided high protection against moderate and severe varicella disease for a period of up to 5 years after vaccination. However, further effectiveness data are needed to assess long-term protection.
authors.affiliation: From the *Department of Paediatrics, University Hospital, Würzburg; †Department of Paediatrics, University Hospital, Munich, Germany; ‡GlaxoSmithKline Vaccines, Wavre, Belgium; §Technical University Hospital, Munich, Germany; and ¶Sanofi Pasteur, Lyon, France.
authors.forename: Johannes G
authors.initials: JG
authors.lastname: Liese
authors.forename: Carine
authors.initials: C
authors.lastname: Cohen
authors.forename: Anita
authors.initials: A
authors.lastname: Rack
authors.forename: Kerstin
authors.initials: K
authors.lastname: Pirzer
authors.forename: Stefan
authors.initials: S
authors.lastname: Eber
authors.forename: Maxim
authors.initials: M
authors.lastname: Blum
authors.forename: Michael
authors.initials: M
authors.lastname: Greenberg
authors.forename: Andrea
authors.initials: A
authors.lastname: Streng
mesh_terms: D016022:Case-Control Studies; D002644:Chickenpox / Q000453:epidemiology* / Q000517:prevention & control*; D019433:Chickenpox Vaccine / Q000008:administration & dosage* / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D005858:Germany / Q000453:epidemiology; D006801:Humans; D007223:Infant; D008297:Male; D011446:Prospective Studies; D013997:Time Factors; D016896:Treatment Outcome; D014611:Vaccination / Q000379:methods*
chemical_list: D019433:Chickenpox Vaccine