Modelling the impact and cost effectiveness of universal varicella vaccination in England

Two distinct diseases are attributable to the varicella zoster virus, varicella (chickenpox) and zoster (shingles). This study assesses the impact and cost-effectiveness of a childhood varicella vaccination program in England.

We use an age-structured dynamic transmission model and a health economic decision tree. The model incorporates recent data on varicella and zoster epidemiology, including the effects of exogenous boosting on zoster incidence. By simulating various vaccination strategies, including routine and catch-up programs, the study evaluates the potential reduction in varicella and zoster cases due to vaccination and the associated vaccine cost-effectiveness (from the NHS perspective).

We find that a two-dose varicella vaccination program could significantly reduce varicella incidence, potentially achieving near-elimination if high coverage rates are maintained. However, the model also predicts a temporary increase in zoster incidence due to reduced natural boosting from varicella exposure; this is partly mitigated by the current zoster vaccination program and the effect is much less substantial than previously estimated. Cost-effectiveness analyses reveal that all vaccination strategies modelled are cost-effective at typical thresholds, with the routine vaccination scenario being the most economically advantageous. Sensitivity analyses demonstrate that vaccine price and varicella treatment costs are the primary drivers of cost-effectiveness.

The study supports the introduction of a childhood varicella vaccination program in England, which offers substantial health benefits and is highly likely to be cost-effective.