The economic case for recombinant zoster vaccine in rheumatoid arthritis

Design

decision-analytic Markov cost-effectiveness model, healthcare payer perspective, lifetime horizon, 4% discounting

Population

hypothetical cohort of 10,000 patients with rheumatoid arthritis

Primary outcome

incremental cost-effectiveness ratio in EUR per quality-adjusted life year versus no vaccination

Effect

EUR 11,205/QALY against a EUR 23,650 threshold; 2,550 zoster and 1,303 postherpetic neuralgia cases averted per 10,000 vaccinated; 98% probability of cost-effectiveness

Herpes zoster is commoner in rheumatoid arthritis, and commoner again on JAK inhibitors, but vaccination rates in rheumatology clinics remain low. A decision-analytic Markov model followed a hypothetical cohort of 10,000 patients with RA over a lifetime through five states — no zoster, zoster, postherpetic neuralgia, recovery and death — comparing adjuvanted recombinant zoster vaccine (RZV) with no vaccination.

Vaccination averted 2,550 cases of zoster and 1,303 cases of postherpetic neuralgia per 10,000 vaccinated, at an incremental cost-effectiveness ratio of EUR 11,205 per quality-adjusted life year against a threshold of EUR 23,650. Probabilistic analysis put the chance of being cost-effective at that threshold at 98%. The result was most sensitive to the probability of postherpetic neuralgia following zoster.

A model is only as good as its inputs, and these were European costs and European epidemiology; the ICER does not transfer to India, where RZV is expensive, largely self-funded and not part of any national schedule. What does transfer is the clinical logic. Postherpetic neuralgia is the driver of both cost and disability, it is commoner in exactly the older, immunosuppressed patients rheumatologists look after, and RZV is a non-live vaccine that can be given on immunosuppression. The practical change is to raise it at the point of starting or escalating therapy, particularly before a JAK inhibitor, rather than leaving it to primary care.

• Raise zoster vaccination when starting or escalating immunosuppression, especially before a JAK inhibitor
• RZV is non-live, so it can be given to patients already on immunosuppression
• Two doses are needed — record the second dose date or it will be missed
• Counsel on cost honestly in India: RZV is self-funded and not in the national schedule
• Postherpetic neuralgia, not zoster itself, is what drives the benefit — say so when patients ask why

The statistics, in plain English

This is a modelled result, not an observed one: the 2,550 zoster cases avoided are what the model predicts from published efficacy and incidence inputs, not events counted in patients. An ICER of EUR 11,205 per QALY sits below the EUR 23,650 threshold used, and the 98% probability of cost-effectiveness comes from varying all inputs together. Because the answer moves most with the rate of postherpetic neuralgia, a setting where that rate is lower would produce a less favourable ratio — and Indian costs and vaccine prices differ enough that the figure should not be quoted here.

Read the rest in the app

You have read your two free briefings this month. The app carries all 27 specialties, every morning, free — and this finding is waiting in it.

Get Daily Doctor — free

Scan to keep reading on your phone. No account needed to start.