Modelling the impact of immunization on the epidemiology of varicella zoster virus

The objective of this study was to develop and apply a dynamic mathematical model of VZV transmission to predict the effect of different vaccination s trategies on the age-specific incidence and outcome of infection. To do so a deterministic realistic age-structured model (RAS) was used which takes a ccount of the increased potential for transmission within school aged group s. Various Vaccine efficacy scenarios, vaccine coverages and vaccination st rategies were investigated and a sensitivity analysis of varicella incidenc e predictions to important parameters was performed. The model predicts tha t the overall (natural and breakthrough) incidence and morbidity of varicel la would likely be reduced by mass vaccination of 12-month-old children. Fu rthermore, adding a catch-up campaign in the first year for 1-11 year olds seems to be the most effective strategy to reduce both. varicella incidence and morbidity tin the short and long term), though with the possible detri mental effect of increasing the incidence of zoster.