Optimal gender-specific age for cost-effective vaccination with adjuvanted herpes zoster subunit vaccine in Chinese adults

Public health impact of herpes zoster vaccination on older adults in Singapore: a modeling study

In Singapore, population aging and rising life expectancy are increasing herpes zoster (HZ) burden, which may be reduced by vaccination. The present study modeled the public health impact of HZ vaccination in Singapore using ZOster ecoNomic Analysis (ZONA) model adapted with Singapore-specific key model inputs, where available. Base case analysis was conducted in adults ≥ 50 years of age (YOA), exploring three vaccination strategies (no vaccination, recombinant zoster vaccine [RZV], zoster vaccine live [ZVL]) under mass vaccination setting (30% coverage). Scenario and sensitivity analyses were performed. Out of 1.51 million adults in 2021 (base case population), 406,513 (27.0%) cases of HZ, 68,264 (4.5%) cases of post-herpetic neuralgia (PHN), and 54,949 (3.6%) cases of other complications were projected without vaccination. RZV was estimated to avoid 73,129 cases of HZ, 11,094 cases of PHN, and 9,205 cases of other complications over the subjects' remaining lifetime; ZVL would avoid 17,565 cases of HZ, 2,781 cases of PHN, and 1,834 cases of other complications. The number needed to vaccinate to prevent one case of HZ/PHN was lower for RZV (7/41) than ZVL (26/163). Among all five age-stratified cohorts (50-59/60-64/65-69/70-79/≥80 YOA), RZV (versus no vaccination/ZVL) avoided the largest number of cases in the youngest cohort, 50-59 YOA. Results were robust under scenario and sensitivity analyses. Mass vaccination with RZV is expected to greatly reduce the public health burden of HZ among Singapore individuals ≥ 50 YOA. Findings support value assessment and decision-making regarding public health vaccination strategies for HZ prevention in Singapore.

Cost-Effectiveness of Varicella Vaccination for 1-4-Year-Olds in Shanghai, China

INTRODUCTION

Varicella has not yet been included in the National Immunization Program (NIP) in China, and varicella vaccination strategies vary by region. To determine the optimal varicella vaccination strategy in Shanghai, China, the cost-effectiveness and 5-year costs of 5 immunization scenarios were analyzed.

METHODS

A static decision tree-Markov model was developed in 2022 to assess the cost-effectiveness and 5-year costs of voluntary and routine varicella vaccination programs in the 2019 birth cohort in Shanghai from a societal perspective. Parameters were collected in 2022 from the varicella surveillance system, a questionnaire survey of 414 guardians of patients with childhood varicella, and semi-structured interviews with 20 experts on varicella outbreaks from different institutions in Shanghai. The outcomes included varicella cases avoided, quality-adjusted life year (QALY) loss, and incremental costs per QALY (ICER). The 5-year costs were compared with local medical expenditures.

RESULTS

Among the 5 scenarios, one dose of routine varicella vaccination was the most cost-saving (USD 70.2) and cost-effective (Dominant) with a 5-year immunization expenditure of USD 9.9 million. Two doses of routine varicella vaccination had the highest QALY (29.9), and its ICER (USD 791.9/QALY) was below the willingness-to-pay threshold (USD 5,203-23,767/QALY). The 5-year immunization expenditure was USD 19.8 million. The effectiveness and price of vaccines, vaccination coverage, and per capita income are the 4 main factors that affect ICERs.

CONCLUSIONS

In Shanghai, the 2 doses of routine varicella vaccination strategy for 1- and 4-year-olds with a 95% coverage rate was found to be the optimal varicella immunization strategy.

Herpes zoster in Belgium: a new solution to an old problem

Herpes zoster (HZ) is caused by reactivation of the varicella-zoster virus. The life-time risk of developing HZ is ~ 30%. Management of HZ can be challenging due to limited efficacy of oral antivirals on pain control, and neuropathic pain that may require aggressive management. Post-herpetic neuralgia (PHN) can cause substantial pain and occurs in up to one-quarter of patients with HZ. Up to 48,000 HZ cases are estimated to occur annually in Belgium, estimated to cost almost 7 million euros in treatment. The recombinant zoster vaccine (RZV, Shingrix, GSK) was approved in Europe in 2017. In 2022, the Belgian Superior Health Council recommended vaccination with RZV for immunocompetent adults aged ≥ 60 years, and immunocompromised patients aged ≥ 16 years, including those receiving immunosuppressive therapy, in particular Janus kinase inhibitors. RZV showed high age-independent efficacy in preventing HZ infection and in clinical trials that has since been confirmed in real-world effectiveness studies. In clinical trials, protection was sustained for at least 10 years after vaccination. As of 1 November 2023, RZV is reimbursed for three immunocompromised patient groups aged ≥ 18 years: malignancy treated in the past 5 years, HIV infection, and organ or haematological stem cell transplantation or are a transplant candidate. HZ is vaccine-preventable and RZV provides a highly effective tool for HZ prevention. While reimbursement for some at-risk groups is welcomed, reimbursement currently falls well short of Superior Health Council recommendations. Adult immunisation strategies should be promoted to achieve high vaccination coverage against HZ, contributing to healthy aging in Belgium.

Cost-effectiveness of the recombinant zoster vaccine (RZV) against herpes zoster: An updated critical review

The objective of this study was to critically review the cost-effectiveness (CE) of the recombinant zoster vaccine (RZV) against herpes zoster (HZ). A literature review was conducted in PubMed, Embase, and Cochrane between January 1, 2017, and February 28, 2022, and on select public healthcare agency websites to identify and collect data from CE studies comparing RZV to zoster vaccine live (ZVL) or to no vaccination. Study characteristics, inputs, and outputs were collected. The overall CE of RZV was assessed. RZV vaccination against HZ is cost-effective in 15 out of 18 studies included in the present review. Varying incremental cost-effectiveness ratios (ICERs) observed may be associated with different assumptions on the duration of protection of RZV, as well as different combinations of structural and disease-related study (model) inputs driving the estimation of ICERs.

How large could the public health impact of introducing recombinant zoster vaccination for people aged ≥50 years in five Latin American countries be?

This study aimed to: (1) estimate the disease burden of herpes zoster (HZ) and (2) assess the potential public health impact of introducing adjuvanted recombinant zoster vaccine (RZV) compared with no vaccination in adults aged ≥50 years in Argentina, Brazil, Mexico, Chile, and Colombia using the ZOster ecoNomic Analysis (ZONA) static multicohort Markov model. The model followed individuals aged ≥50 years from administration of RZV over their remaining lifetime. Inputs were based, most often, on local data. First dose coverage was assumed to be 35%, with 75% second dose compliance. It was predicted that without RZV, there would be 23,558,675 HZ cases, 6,115,981 post-herpetic neuralgia (PHN) cases, and 7,058,779 non-PHN complications in the five countries, but introducing RZV under assumed coverage could avoid 4,583,787 (19%) HZ cases, 1,130,751 (18%) PHN cases, and 1,373,419 (19%) non-PHN complications. Also, 10427,504 (20%) doctor's office visits and 1,630,201 (19%) days of hospitalization could be averted in the three countries (Argentina, Brazil, and Mexico) with available input data. The numbers needed to be vaccinated to avoid one case of HZ were 9-10 across countries, and to avoid one case of PHN, 35-40. One-way sensitivity analyses showed that the input parameters with the largest impact on the estimated number of HZ cases avoided were first dose coverage, initial HZ incidence, and vaccine efficacy waning. In conclusion, the introduction of RZV for older adults in Latin America could greatly reduce the public health burden of HZ and reduce the related doctor visits and hospitalization days.

Public health impact of herpes zoster vaccination on older adults in Hong Kong

The growing burden of herpes zoster (HZ) in Hong Kong, due to an aging population with increasing life expectancy, may be reduced by vaccination. This study aimed to estimate public health impact of HZ vaccination in Hong Kong. The ZOster ecoNomic Analysis (ZONA) model was adapted with Hong Kong-specific key model inputs/assumptions, where available. Base case analysis involved adults ≥50 years of age (YOA), exploring three vaccination strategies (no vaccination/recombinant zoster vaccine [RZV]/zoster vaccine live [ZVL]) under private market (5% coverage) and mass vaccination (40% coverage) settings. Scenario and sensitivity analyses were performed. In the base case population (3.13 million), without vaccination, 891,024 HZ (28.4%), 156,097 post-herpetic neuralgia (PHN) (5.0%), and 38,755 (1.2%) HZ ophthalmicus (HZO) were projected over their remaining lifetime. Mass RZV vaccination reduced HZ, PHN, and HZO cases by 204,875 (-23.0%), 31,949 (-20.5%), and 8,471 (-21.9%), respectively, which was 4-5 times that reduced with ZVL. RZV was more efficient than ZVL, with lower number needed to vaccinate to prevent one HZ/PHN/HZO case (RZV: 7/40/148; ZVL: 27/163/709). Among all age cohorts, the greatest reduction in cases was projected for RZV (versus no vaccination/ZVL) in the youngest cohort, 50-59 YOA. Results were robust under scenario and sensitivity analyses. HZ burden in Hong Kong is substantial. Mass RZV vaccination is expected to considerably reduce public health burden of HZ among individuals ≥50 YOA, compared with no vaccination/ZVL. Results may support value assessment and decision-making regarding vaccination strategies for HZ prevention in Hong Kong.

Cost-Effectiveness of Recombinant Zoster Vaccine for Adults Aged ≥50 Years in China

INTRODUCTION

Adjuvanted recombinant zoster vaccine (RZV) was the first vaccine made available for herpes zoster in China. Authors aimed to evaluate its economic and health impacts on Chinese adults aged ≥50 years.

METHODS

A lifetime Markov model was developed to compare the cost-effectiveness of RZV with that of no vaccination from a societal perspective. Model inputs were derived from published literature and analyzed in 2022. Outcomes included total costs, quality-adjusted life-years, incremental cost-effectiveness ratio, and number of herpes zoster and herpes zoster-related cases. Sensitivity analyses were performed to examine the robustness of the model results.

RESULTS

RZV was more costly than no vaccination by $2.78 billion with an additional 65,008 quality-adjusted life-years gained and could avoid 1,893,530 herpes zoster cases, 295,761 postherpetic neuralgia cases, 51,734 other complications, and 229 herpes zoster-related deaths. Incremental cost-effectiveness ratios of RZV varied in a range of $34,465.5-$51,002.7 per quality-adjusted life-year. RZV for the entire cohort would be cost-effective when discount rate was <2.4%, a waning rate of 2-dose RZV efficacy decreased to <0.8%, the utility of postherpetic neuralgia was <0.496, duration of postherpetic neuralgia was >12.86 months, or the cost of RZV per dose decreased to <$229.6. In a probabilistic sensitivity analysis, the probability of RZV being cost-effective was 43.95%, 59.32%, 45.27%, and 39.50% for people aged 50-59, 60-69, 70-79, and ≥80 years, respectively, with threefold gross domestic product per capita (37,654.5 per quality-adjusted life-year) as the willingness-to-pay threshold.

CONCLUSIONS

RZV was most likely to be cost-effective in people aged 60-69 years. A slight decrease in vaccine cost would result in RZV being cost-effective in all people aged ≥50 years.

Incremental net monetary benefit of herpes zoster vaccination: a systematic review and meta-analysis of cost-effectiveness evidence

OBJECTIVES

To perform a systematic review and meta-analysis to pool the incremental net benefit (INB) of each herpes zoster vaccine [i.e. Zoster Vaccine Live (ZVL) and Recombinant Zoster Vaccine (RZV)].

METHODS

We initially identified individual studies by hand-searching reference lists of the relevant systematic review articles. An updated comprehensive search was performed in Medline, Scopus, and Embase until June 2020 for additional studies. Studies were eligible if they assessed the cost-effectiveness/utility of any pair among ZVL and RZV, and no vaccine and reported economic outcomes. Details of the study characteristics, economic model inputs, costs, and outcomes were extracted. INB was calculated with monetary units adjusting for purchasing power parity for 2019 US dollars and pooled by meta-analysis.

RESULTS

A total of 37 studies were pooled for meta-analysis stratified by perspectives [i.e. societal (SP) and third-party payer (TPP)] and vaccine types. In SP, ZVL was cost-effective compared to no vaccine when vaccinated at ages of 50-59 and 70-79 years with INBs (95% CI) of $0.61 (0.37, 0.85) and $9.67 (5.20, 14.14), respectively. RZV was cost-effective for those aged 60-69 and 70-79 years with INBs of $75.61 (17.98, 133.23) and $85.01 (30.02, 140.01), respectively. In TPP, ZVL was cost-effective compared to no vaccine when vaccinated at age 70-79 years with INB of $7.57 (0.27, 14.86) and RZV was cost-effective at 60-69 years with INB $220.87 (47.80, 393.93). The cost-effectiveness of RZV was robust across a series of sensitivity analyses, but ZVL differs on different vaccination ages.

CONCLUSIONS

RZV may be cost-effective for vaccination in ages of 60-79 years for both SP and TPP perspectives, while ZVL might be cost-effective in some age groups, but results are not robust.

Inclusion of Additional Unintended Consequences in Economic Evaluation: A Systematic Review of Immunization and Tuberculosis Cost-Effectiveness Analyses

OBJECTIVE

Our objective was to review economic evaluations of immunization and tuberculosis to determine the extent to which additional unintended consequences were taken into account in the analysis and to describe the methodological approaches used to estimate these, where possible.

METHODS

We sourced the vaccine economic evaluations from a previous systematic review by Nymark et al. (2009-2015) and searched PubMed/MEDLINE and Embase from 2015 to 2019 using the same search strategy. For tuberculosis economic evaluations, we extracted studies from 2009 to 2019 that were published in a previous review by Siapka et al. We followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidance. Studies were classified according to the categories and subcategories (e.g., herd immunity, non-specific effects, and labor productivity) defined in a framework identifying additional unintended consequences by Nymark and Vassall. Where possible, methods for estimating the additional unintended consequences categories and subcategories were described. We evaluated the reporting quality of included studies according to the Consolidated Health Economic Evaluation Reporting Standards (CHEERS) extraction guideline.

RESULTS

We identified 177 vaccine cost-effectiveness analyses (CEAs) between 2009 and 2019 that met the inclusion criteria. Of these, 98 included unintended consequences. Of the total 98 CEAs, overall health consequence categories were included 73 times; biological categories: herd immunity 43 times; pathogen response: resistance 15 times; and cross-protection 15 times. For health consequences pertaining to the supply-side (health systems) categories, side effects were included five times. On the nonhealth demand side (intrahousehold), labor productivity was included 60 times. We identified 29 tuberculosis CEAs from 2009 to 2019 that met the inclusion criteria. Of these, six articles included labor productivity, four included indirect transmission effects, and one included resistance. Between 2009 and 2019, only 34% of tuberculosis CEAs included additional unintended consequences, compared with 55% of vaccine CEAs.

CONCLUSIONS

The inclusion of additional unintended consequences in economic evaluations of immunization and tuberculosis continues to be limited. Additional unintended consequences of economic benefits, such as those examined in this review and especially those that occur outside the health system, offer valuable information to analysts. Further work on appropriate ways to value these additional unintended consequences is still warranted.

Varicella zoster virus vaccines: an update

Varicella zoster virus (VZV) is the etiological agent of varicella, a highly infectious, self-limiting disease with serious complications. The decline in cell-mediated immunity (CMI) that occurs with aging or immunodepression causes a reactivation of the latent VZV as herpes zoster (HZ). Prevention of VZV through varicella vaccination strategies allows to avoid the primary infection in newborns and susceptible subjects. Available monovalent and combined VZV vaccines are effective, safe and generally well tolerated. Universal varicella vaccination has significantly impacted on incidence, complications and deaths related to this disease. Prevention of HZ through vaccination is a priority to avoid the significant burden of its incidence and complications. Currently two HZ vaccines are available. The recombinant zoster vaccine (RZV), approved by the FDA in 2017 and Zoster Vaccine Live (ZVL) licensed in the United States by the FDA in 2006. The advisory committee on immunization practices (ACIP) preferentially recommends RZV. ZVL remains an option for prevention of HZ in immunocompetent adults aged ≥60 years, although the CMI tends to wane a few years after vaccination.