SHINGLES VACCINE FOR RHEUMATOID ARTHRITIS PATIENTS: SHOULD WE GIVE IT A SHOT?

Purpose: Shingles is a reactivation of latent varicella zoster virus (chickenpox) decades after the initial infection. The vaccine against shingles is licensed for individuals aged 60 years old and older with no contraindications. The vaccine is not recommended to patients with immunocompromised diseases, such as rheumatoid arthritis (RA). There is a theoretical concern that the vaccine may increase the induced risk of shingles in these patients. We aim to evaluate the clinical and economic impact of the live, attenuated shingles vaccine among patients with RA and assess the potential value of the vaccine for society and payers.

Method: We developed a Markov analytic model to simulate a hypothetical cohort of RA patients under two different strategies: vaccination against shingles and no vaccination. Individuals from this cohort face a monthly risk of developing shingles and those with shingles can develop a cutaneous rash dissemination with a risk of turning into visceral dissemination. Visceral dissemination imposes and added cause of mortality. Individuals with shingles can develop postherpetic neuralgia, a prolonged permanent pain. The primary outcomes of interest are the incidence of herpes zoster, the incidence of severe zoster-related complications, the total direct healthcare costs (measured in 2014 US dollars), and quality-adjusted life-years (QALYs) accrued over the lifetime of the cohort. We varied the starting age of the cohort from 40 to 70 years old. The parameters of the model were estimated from the literature.

Result: The vaccine is cost-effective at a willingness to pay of $50,000 per QALY. The vaccine is the optimal strategy as long as the induced risk of shingles is lower than 0.001. Estimates derived from observational studies, suggest that the induce risk might be well below this threshold. We evaluated an early vaccine scenario in which 40-year-old individuals get the vaccine before developing RA, which resulted in an optimal strategy.

Conclusion: The vaccine reduces the incidence of shingles and related complications in RA patients. It also increases the QALYs and reduces the cost by lowering shingles-related hospital utilization. We suggest that current recommendations of the shingles vaccine in immunocompromised patients should be reconsidered. An earlier starting age of vaccination might result in an improved recommendation as long as there are no side effects imposed by the vaccine.