Table 3.
Main results and selected sensitivity analyses (univariate, multivariate, and scenario analyses) results reported as incremental cost-effectiveness ratios ($/QALY), comparing vaccination with recombinant zoster vaccine (RZV) to no vaccination, from a cost-effectiveness model of herpes zoster vaccination among HCT recipients and patients with selected immunocompromising conditions, adults aged 19—49 years.
| Main result | Incremental cost-effectiveness ratio ($/QALY) |
|---|---|
| HCT recipients (i.e., base case) | Cost-savinga |
| Selected univariate analyses b | |
| Low rate of waning protection among 2 dose recipients | 133,000 |
| 20 years to final IC state from general risk state (i.e., longer duration of general risk state) | 133,000 |
| More severe (i.e., low value) QALY weight for local, mild AEs | Lower costs & lower QALYsc |
| More severe (i.e., low value) QALY weight for systemic, mild AEs | Lower costs & lower QALYsc |
| Low costs for inpatient HZ episodes | 32,000 |
| Selected multivariate analyses d | |
| All VE inputs (i.e., low initial VE and high rates of waning protection for 1 and 2 doses) | 353,000 |
| More severe (i.e., low values) QALY weights for all AE types | Lower costs & lower QALYs |
| Low costs for all HZ outcomes (i.e., uncomplicated, inpatient, PHN episodes) | 45,000 |
| Low costs for all HZ outcomes and high costs for vaccine doses and all AE types | 58,000 |
| Scenario analyses e | |
| Multiple myeloma | Cost-saving |
| Non-Hodgkin lymphoma | 165,000 |
| Hematologic malignancies | 9,500 |
| HIV | 79,000 |
| Autoimmune/inflammatory conditions | 208,000 |
| Varicella vaccination | Cost-saving |
Note(s): HZ = herpes zoster; IC = immunocompromised; QALY = quality-adjusted life-year; RZV = recombinant zoster vaccine. Numeric values were rounded to nearest 1,000 or 100 to improve readability. All costs are reported in US$2020.
Base case results were cost-saving, with negative incremental costs and positive incremental health outcomes.
Additional univariate sensitivity analyses were conducted but not presented here. These additional analyses all found cost-savings using high and low input values, and included: age distribution, antiviral duration, initial VE (1 dose), initial VE (2 dose), waning protection (1 dose), probability AE (local, grade 3), probability AE (systemic, grade 3), probability AE (severe), years to general risk, incidence (given IC status), incidence (given general status), probability PHN (given HZ), probability inpatient (given HZ), probability death (given HZ and IC status), probability death (given HZ and general status), background mortality (IC multiplier), background utilities (age-based), background utilities (IC multiplier), utility weight (HZ episode), utility weight (HZ with PHN episode), utility weight (inpatient HZ episode), utility adjustment for breakthrough HZ episode, utility weight (AE local, mild), utility weight (AE systemic, grade 3), utility weight (AE severe), cost vaccine dose, cost HZ episode, cost PHN, cost AE (local, mild), cost AE (local, grade 3), cost AE (systemic, mild), cost AE (systemic, grade 3), cost (AE severe).
Lower costs & lower QALYs indicates negative incremental costs and negative incremental health outcomes, which would be a less preferred outcome than a cost-saving result, such as was found in the base case which is characterized by negative incremental costs and positive incremental health outcomes (i.e., higher QALYs).
Additional multivariate sensitivity analyses were conducted but not presented here. These additional analyses all found cost-savings using high and low input values, and included: probability all AE events, probability all severe HZ outcomes, utility loss (all HZ episode types), cost (all HZ outcomes), cost (all cost inputs). An analysis where the upper age limit was changed from 50 to 100 years was also conducted, which found cost-savings.
Input values used in the scenario analyses are presented in Table 2.