Newly Approved Recombinant Zoster Vaccine Provides Better Value, Lower Costs

The new recombinant zoster vaccine (RZV), approved by the US Food and Drug Administration and recommended by the Advisory Committee on Immunization Practices in October 2017, features a lower cost-effectiveness ratio than other recommended adult vaccines, including the zoster vaccine live (ZVL), according to results of a study published in the Annals of Internal Medicine.

The researchers used a herpes zoster state-transition simulation model to compare 2-dose RZV with ZVL, and with no vaccination, in terms of projected costs and health outcomes. These outcomes were simulated from a hypothetical cohort of immunocompetent patients in the United States (aged ≥50 years), stratified by age. The incremental cost-effectiveness ratio comprised the primary outcome for the analysis. Two of the studies included provided information on the direct medical costs of uncomplicated herpes zoster infection, and 3 studies were used to obtain data on productivity losses per case for herpes zoster infection.

In the base-case analysis, the incremental cost-effectiveness ratio of the RZV vaccine vs no vaccine was age-dependent and ranged from $10,000-$47,000 per quality-adjusted life-year. These findings were based on a societal perspective as well as the assumption that there was a 100% completion rate for the 2-dose RZV regimen. Researchers noted that ZLV yielded higher costs and fewer health benefits compared with RZV, across all age groups. For individuals aged ≥60 years, the incremental cost-effectiveness ratio was $19,000 and $29,000 per quality-adjusted life-year from the societal and health care sector perspectives, respectively. For all age groups ≥60 years, more individuals were vaccinated with ZVL than RZV.

Of note, in people who had previously been vaccinated with ZVL, the incremental cost-effectiveness ratios were below $60,000 per quality-adjusted life-year for all age groups except people aged 60 to 69 years who were vaccinated with RZV immediately after vaccination with ZVL. In addition, those under the age of 60 years had the highest incremental cost-effectiveness ratio at all periods of revaccination compared with other age groups.

The sensitivity analysis revealed similar findings. Patients vaccinated with RZV following a prior vaccination with ZVL had an overall incremental cost-effectiveness ratio of <$60,000 per quality-adjusted life-year for patients aged ≥60 years. The preferred vaccine strategy was RZV in at least 95% of simulations for patients aged ≥60 years, with this strategy also preferred in those with up to 50% completion in the second vaccine dose.

Limitations of the analysis included the assumption of 100% successful completion of the vaccine series, the lack of robust data on the risk of serious adverse events, the probability of recurrent zoster, and the overall adherence to the 2-dose vaccination protocol.

In an accompanying editorial, Stephen D. Shafran, MD, explained that the current challenge in administering the RZV is in the need for a second dose. “Clinical trial patients tend to be highly motivated, and trial staff typically try much harder than staff in routine clinical care to ensure that participants complete all study procedures,” Dr Shafran explained.² “Lower completion rates of the second dose will surely occur in the ‘real world.’ He cited data from 1 of the few studies that has examined completion rates of multiple-dose vaccines in adults:  only 43.6% for patients aged 50 years or older, the same age range recommended for RZV, obtained the second dose of the hepatitis A within 1 year of the first dose.

References

1. Prosser LA, Harpaz R, Rose AM, et al. A cost-effectiveness analysis of vaccination for prevention of herpes zoster and related complications: input for national recommendations [published online February 19, 2019]. Ann Intern Med. doi: 10.7326/M18-2347
2. Shafran SD. Prevention of shingles: better protection and better value with recombinant vaccine [published online February 19, 2019]. Ann Intern Med. doi: 10.7326/M19-014