This is the first large-scale study to investigate the seroprevalence of varicella zoster (VZV) in the general population of England and Wales. The study focused on those aged 1-20 years, that age group in whom most infections occur. Prevalence rose rapidly with age, with 53% of children showing evidence of prior infection by the age of 5 years and most young adults having experienced infection. In addition to using a fixed cut-off recommended by the manufacturer, a mixture modelling technique was also used to define the proportion of the population seropositive in each age group. This was shown to be a more accurate approach to categorizing data from an epidemiological perspective.