The epidemiology of varicella in school-aged Greek children before the implementation of universal vaccination.

Data on local epidemiology is necessary when deciding on the introduction of a vaccine. Parents of children attending 1st and 6th grades completed a questionnaire on demographical data and varicella history. Analyzing 70,226 questionnaires, varicella was reported in 63.6% and 78.6% of 1st and 6th grade children, respectively (mean age 4.75 years), indicating that a quarter of children entering adolescence are susceptible. Children attending day care and children with older siblings had contracted chickenpox at a younger age. In conclusion, in Greece, in addition to introducing universal varicella vaccination, it is necessary to identify older children at risk and offer catch-up vaccination.