Varicella vaccination in England and Wales: cost-utility analysis.

AIMS To assess the cost-effectiveness of varicella vaccination, taking into account its impact on zoster. METHODS An age structured transmission dynamic model was used to predict the future incidence of varicella and zoster. Data from national and sentinel surveillance systems were used to estimate age specific physician consultation, hospitalisation, and mortality rates. Unit costs, taken from standard sources, were applied to the predicted health outcomes. RESULTS In England and Wales, the annual burden of VZV related disease is substantial, with an estimated 651 000 cases of varicella and 189 000 cases of zoster, resulting in approximately 18 000 QALYs lost. The model predicts that although the overall burden of varicella will significantly be reduced following mass infant vaccination, these benefits will be offset by a significant rise in zoster morbidity. Under base case assumptions, infant vaccination is estimated to produce an overall loss of 54 000 discounted QALYs over 80 years and to result in a net cost from the health provider (NHS) and the societal perspectives. These results rest heavily on the impact of vaccination on zoster. Adolescent vaccination is estimated to cost approximately 18 000 pounds sterling per QALY gained from the NHS perspective. CONCLUSION Routine infant varicella vaccination is unlikely to be cost-effective and may produce an increase in overall morbidity. Adolescent vaccination is the safest and most cost-effective strategy, but has the least overall impact on varicella.