A health economic model for evaluating a vaccine for the prevention of herpes zoster and post-herpetic neuralgia in the UK

BACKGROUND: A live-attenuated vaccine aimed at preventing herpes zoster (HZ) and its main complication, post-herpetic neuralgia (PHN) is available in Europe for immunocompetent adults aged 50 years and more. The study objective is to assess the cost effectiveness of a vaccination program for this population in the UK. METHODS: A state-transition Markov model has been developed to simulate the natural history of HZ and PHN and to estimate the lifetime effects of vaccination in the UK. Several health states are defined including good health, HZ, PHN, and death. HZ and PHN health states are further divided to reflect pain severity. RESULTS: The model predicts that a vaccination strategy for those aged over 50 years would lead to an incremental cost-effectiveness ratio of £13,077 per QALY gained from the NHS perspective, when compared to the current strategy of no vaccination. Age-group analyses show that the lowest ICERs (£10,984 and £10,275 for NHS) are observed when vaccinating people between 60-64 and 65-69 years of age. Sensitivity analyses showed that results are sensitive to the duration of vaccine protection, discount rate, utility decrements and pain severity split used. CONCLUSIONS: Using the commonly accepted threshold of £30,000 per QALY gained in the UK, most scenarios of vaccination programmes preventing HZ and PHN, including the potential use of a repeat dose, may be considered cost-effective by the NHS, especially within the 60 to 69 age-groups.