Cost-Effectiveness Analysis of Vaccination With Recombinant Zoster Vaccine Among Hematopoietic Cell Transplant Recipients and Persons With Other Immunocompromising Conditions Aged 19 to 49 Years

Cost-effectiveness and public health impact of recombinant zoster vaccine versus no herpes zoster vaccination in selected populations of immunocompromised adults in Canada

BACKGROUND

The risk of herpes zoster (HZ) increases with age and in immunocompromised (IC) patients. Recombinant zoster vaccine (RZV) is currently recommended in Canada for people aged ≥ 50 years. The objectives of the current study were to evaluate the cost-effectiveness and public health impact of RZV versus no HZ vaccination in select Canadian IC adult populations.

METHODS

The ZOster ecoNomic Analysis ImmunoCompromised (ZONA IC) model followed a base-case cohort of 1600 patients with hematopoietic stem-cell transplant (HSCT) from a starting age of 55 years, who maintained IC status for 5 years, from a societal perspective. Scenario analyses were conducted for patients with breast cancer, renal transplant, human immunodeficiency virus (HIV), and Hodgkin lymphoma. These probabilistic analyses used a life-long time horizon and discount rates of 1.5% for costs and quality-adjusted life-years (QALYs). First-dose coverage was assumed to be 60% and second-dose completion 100%. Deterministic one-way sensitivity analysis for the base case was performed. Costs are reported in 2022 Canadian dollars, with an assumed cost-effectiveness threshold of $50,000 per QALY gained.

RESULTS

In the base-case analysis (HSCT), it was estimated that RZV would prevent medians of 116 HZ and 27 postherpetic neuralgia (PHN) cases, respectively versus no HZ vaccination. Estimated median numbers needed to vaccinate were 8 and 35 to avoid one HZ and one PHN case, respectively. The median incremental cost-effectiveness ratio (ICER) was $22,648 per QALY gained and was most sensitive to assumptions of HZ incidence, direct medical costs for unvaccinated HZ without PHN, and RZV efficacy against PHN. In other IC populations, estimated median ICERs were $24,328 (breast cancer), $27,237 (renal transplant), $67,207 (HIV), and $81,470 (Hodgkin lymphoma).

CONCLUSIONS

RZV in Canada improves public health outcomes and is likely cost-effective for several IC conditions.

Retraction notice to Cost-effectiveness of the Recombinant Zoster Vaccine among People Living with Human Immunodeficiency Virus in Japan: [VHRI Volume 44, November 2024, 101025]

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/policies/article-withdrawal). This article has been retracted at the request of the authors due to an error in the study discovered after the paper was published. In this study, the cost-effectiveness of the recombinant zoster vaccine (RZV) (Shingrix®) for people living with HIV (PLWHIV) aged ≥50 years was analyzed, comparing a 2-dose RZV strategy to no RZV strategy. The initial model indicated that the no RZV strategy was more cost-effective than the 2-dose RZV strategy (Erratum to Table 2). However, an error occurred in the model, where the cost parameter for the 2-dose RZV strategy was mistakenly applied as if PLWHIV individuals received the 2-dose vaccine in every cycle, significantly inflating the cost of this strategy. Upon correcting the model to reflect that the 2-dose RZV is administered only at cycle 0, the revised results indicate that the 2-dose RZV strategy is dominant over the no RZV strategy (Erratum to Table 2). Given that this error leads to a completely reversed conclusion, this paper has been retracted.

Public health impact of recombinant zoster vaccine for prevention of herpes zoster in US adults immunocompromised due to cancer

Individuals who are immunocompromised (IC) due to therapy or underlying disease are at increased risk of herpes zoster (HZ). This study evaluates the public health impact of recombinant zoster vaccine (RZV) relative to no HZ vaccination for the prevention of HZ among adults aged ≥18 years diagnosed with selected cancers in the United States (US). A static Markov model was used to simulate three cohorts of individuals who are IC with cancer (time horizon of 30 years; one-year cycle length): hematopoietic stem cell transplant (HSCT) recipients, patients with breast cancer (BC; a solid tumor example), and patients with Hodgkin's lymphoma (HL; a hematological malignancy example). Cohort sizes reflect the estimated annual incidence of each condition in the US population (19,671 HSCT recipients, 279,100 patients with BC, and 8,480 patients with HL). Vaccination with RZV resulted in 2,297; 38,068; and 848 fewer HZ cases for HSCT recipients, patients with BC, and patients with HL, respectively (each versus no vaccine). Vaccination with RZV also resulted in 422; 3,184; and 93 fewer postherpetic neuralgia cases for HSCT, BC, and HL, respectively. Analyses estimated the quality-adjusted life years gained to be 109, 506, and 17 for HSCT, BC, and HL, respectively. To prevent one HZ case, the number needed to vaccinate was 9, 8, and 10, for HSCT, BC, and HL, respectively. These results suggest RZV vaccination may be an effective option to significantly reduce HZ disease burden among patients diagnosed with selected cancers in the US.

Cost-Effectiveness of Recombinant Zoster Vaccine for the Prevention of Herpes Zoster in Hematopoietic Stem Cell Transplant Recipients and Other Immunocompromised Adults in the United States

INTRODUCTION

Immunocompromised (IC) adults are at increased risk of developing herpes zoster (HZ) and HZ-related complications due to therapy or underlying disease. This study evaluated the cost effectiveness of recombinant zoster vaccine (RZV) versus no vaccine for the prevention of HZ in hematopoietic stem cell transplant (HSCT) recipients and other IC adults aged ≥ 18 years in the United States (US).

METHODS

A static Markov model simulated cohorts of IC individuals using a 1-year cycle length and 30-year time horizon to estimate the cost effectiveness of RZV. Inputs were sourced from clinical trial results and publicly available sources/literature. Modeled populations included US adult HSCT recipients (base case), patients with human immunodeficiency virus (HIV), patients with breast cancer, patients with Hodgkin's lymphoma, and renal transplant recipients. The model reported societal costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios (ICERs). Sensitivity and threshold analyses were conducted.

RESULTS

In the base case of 19,671 US adult HSCT recipients, RZV resulted in total societal cost savings of US$0.1 million and 109 incremental QALYs versus no vaccine. RZV was a 'dominant strategy' versus no vaccine because vaccination resulted in cost savings with QALY gains. RZV was also cost saving in renal transplant recipients, and cost effective at a willingness-to-pay threshold of US$100,000 per QALY gained in patients with HIV, breast cancer, and Hodgkin's lymphoma, with ICERs of US$33,268, US$67,682, and US$95,972 per QALY gained, respectively, versus no vaccine.

CONCLUSIONS

Model results show RZV is potentially cost saving for the prevention of HZ in US adult HSCT recipients and US adults with selected immunocompromising conditions, and cost effective for others, supporting the use of RZV to prevent HZ and HZ-related complications in IC adults.