An Economic Evaluation of Herpes Zoster Vaccination With the Recombinant Vaccine for Adults in Ireland

OBJECTIVES: Herpes zoster (HZ) is caused by reactivation of the varicella zoster virus. It mainly affects adults and is characterised by a vesicular skin rash, associated with itching and pain, generally lasting up to four weeks. For those that have had chickenpox, the lifetime risk of developing HZ is approximately 30%. This study aimed to estimate the cost utility of vaccination with the recombinant HZ vaccine for the general adult population in Ireland.

METHODS: Using a closed-cohort Markov model, eight alternative two-dose vaccination strategies were assessed: vaccination of people turning 50, 55, 60, 65, 70, 75, 80 and 85 years of age. Clinical effectiveness against incidence of HZ, hospitalisation and post herpetic neuralgia was included in the model. Costs were expressed in 2023 Irish Euro. The analysis considered both the publicly-funded healthcare system and societal perspectives and used a base-case vaccine cost of €151 (ex-VAT) per dose. Sensitivity and scenario analyses were conducted to investigate parameter and structural uncertainty. The willingness-to-pay (WTP) threshold was €45,000 per quality-adjusted life-year (QALY).

RESULTS: From both the payer and societal perspectives, the incremental cost-effectiveness ratios for all HZ vaccination strategies assessed exceeded the WTP threshold. The results of the economic evaluation were robust to probabilistic and one-way sensitivity analysis and various scenario analyses. Based on the model assumptions, the vaccine cost would need to be less than €30 per dose for vaccination at 75 and 80 years old to be cost effective at the WTP threshold.

CONCLUSIONS: From the payer and societal perspectives, vaccination of adults in the general population against HZ, at ages ranging from 50 to 85 years, would not be considered cost effective at a base-case vaccine cost of €151 per dose. Substantial price reductions would be necessary for vaccination of adults in the general population against HZ to be considered cost-effective.