A laboratory study of age-related varicella incidence and prevalence in the Czech Socialist Republic.

During 1972-1981, ten representative population samples totalling 2,916 individuals were tested for antibodies to varicella-zoster virus (VZV) by an indirect-haemagglutination assay (IHA). Statistical analysis of the results provided estimates of age-related varicella prevalence and incidence rates. It transpired that 45% of the child population had encountered varicella at preschool age and another 45% during the attendance of school. Adult seropositivity rates amounted to 97.5-100%. The highest varicella incidence was observed in the 4-year age interval of 2-6 years. For control, additional 324 and 297 individuals were tested by RIA and ELISA IgG, respectively; there was good correlation of results. For the period 1970-1985 varicella morbidity was also studied from notification data. As far as the authors are aware, the present investigation performed on a total of 3,537 subjects furnishes the most comprehensive information on nation-wide varicella incidence and prevalence obtained by laboratory methods.