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

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.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.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.In our aging society, diseases whose prevalence rises with age are of increasing significance. The varicella zoster virus (VZV) causes chickenpox as the primary infection. Reactivation of the dormant virus in the dorsal root ganglia of individuals having had a primary infection can occur, causing herpes zoster (HZ) or "shingles". The lifetime risk of suffering from HZ is 25% [1]. HZ incidence increases sharply with age, roughly doubling in each decade past the age of 50 years [2]. Normal age-related decrease in varicella zoster-specific cell-mediated immunity is thought to account for this increased incidence of VZV reactivation. The symptoms of HZ include numbness, itching and pain during the prodromal phase (before the rash onset), followed by painful unilateral vesicular eruptions on the skin. The pain and cutaneous eruptions usually subside after 3-4 weeks