This study is undertaken to evaluate the effectiveness of currently licensed varicella vaccines under conditions of routine use in a setting where varicella vaccine is included in the childhood immunization calendar.

Observational, multicenter, population-based, matched case-control study conducted in selected pediatric practices in the Munich area.

Inclusion Criteria:

• Male or female child at least one year of age, born on or after July 1 2003.
• Residence in Germany
• At least one previous well-child visit to the practice
• Written informed consent obtained from parents/guardians of the subject as per local requirements.
• Specific inclusion criterion for cases:
• Suspected primary varicella disease (i.e. chickenpox) at the time of study entry

Exclusion Criteria:

• Ineligible for varicella vaccination, due to any medical contraindication. These contraindications are:

  • History of hypersensitivity to any of the components of the vaccines
  • Congenital or acquired immunodeficiency
  • Treatment with immunosuppressive therapy
  • HIV-infected patients, when CD4 < 25% of total lymphocytes
  • Previous history of chickenpox by physician record or parental report.
  • Lack of documented vaccination history (written or computerised practice records or child's vaccination card/booklet).

All children 12 months of age or older and born on or after 1 July 2003 whose parents contact the pediatrician at the selected sites for suspected varicella after study start. Pediatric practices in Munich and the Munich area will be initially selected.