OBJECTIVES:

The one-dose live-attenuated HZ vaccine was introduced into the UK vaccination programme for the elderly in September 2013. An alternative investigational two-dose HZ/su vaccine is currently in development. To investigate the overall health and economic benefits of the one-dose HZ vaccine in comparison to the investigational two-dose vaccine in the UK programme.

METHODS:

A Markov model was developed to compare the economic impact and case burden of HZ and postherpetic neuralgia (PHN) for the two types of vaccine in the UK for adults aged 70 to 79 years old. Vaccine effectiveness assumptions were taken from a recent observational study from Kaiser Permanente Northern California for the one-dose HZ vaccine, while assumptions for the investigational vaccine were taken from the clinical trial publications. However, a key limitation is the lack of data on the investigational vaccine’s first dose efficacy and duration. Hence a first dose efficacy range of 25% - 65% and duration of one year were modelled. Different series completion rates were applied for the two-dose vaccine varying from 45% - 75%, based on compliance rates reported for hepatitis vaccines in adults. The waning of the investigational HZ/su vaccine after 2 doses was assumed to be either 15 years or 20 years.

RESULTS:

For 1000 vaccinated individuals, the one-dose HZ vaccine prevented more cases of HZ and PHN than the two-dose investigational HZ/su vaccine when the two-dose completion rate was at 45% and the efficacy for the first-dose was 25%.

CONCLUSIONS:

The one-dose HZ vaccine could lead to better health and economic benefits if the two-dose investigational HZ/su vaccine cannot achieve very high series completion rate in a real world situation. Given the uncertainties about one-dose efficacy and duration of effect, further analyses are needed to determine the likely overall impact of the two-dose vaccine in the UK.