Health economic evaluation of a vaccine for the prevention of herpes zoster (shingles) and post-herpetic neuralgia in adults in Belgium

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.

The Number Needed to Vaccinate (NNV) against herpes zoster: a systematic review with meta-analysis

OBJECTIVES

The number needed to vaccinate (NNV) quantifies the effectiveness of vaccination programs. We summarised the published data on NNV against herpes zoster to inform vaccination policies.

METHODS

We systematically identified studies based on a priori established and registered methods. The main outcomes were the NNV against herpes zoster infection, hospitalisation and mortality. Where appropriate, we conducted meta-analyses using inverse variance, random-effects models, pooling estimated NNV with associated 95% confidence interval (CI). Statistical heterogeneity between pooled estimates was calculated using the I² statistic.

RESULTS

Out of 229 unique citations, we included eight nonrandomized studies. Among 50+ year-olds, the NNV against herpes zoster infection using the recombinant subunit vaccine was 11 (95%CI 8-14; I² = 0%; 3 studies) and variable (I² = 94.4%; 7 studies) using live attenuated vaccine, ranging from 10 (95%CI 1-19) to 58 (95%CI 49-67). Among 65+ year-olds, the NNV against herpes zoster infection using the recombinant subunit vaccine was 12 (95%CI: 9-15; I² = 0%; 2 studies) and variable (I² = 98.5%; 4 studies) using live attenuated vaccine, ranging from 14 (95%CI 5-23) to 75 (95%CI 66-84). The NNV against herpes zoster hospitalisation among 65+ year-olds using the live attenuated vaccine was 280 (95%CI 209-352; I² = 0%; 2 studies). There was a paucity of data to inform other meta-analyses.

CONCLUSION

Evidence on the NNV against herpes zoster is scarce. Vaccination with the recombinant subunit herpes zoster vaccine may be more effective than with the live attenuated vaccine in preventing infection among 50+ year-olds. More studies are needed for a stronger evidence base for decision-making.

The Use of Expert Elicitation among Computational Modeling Studies in Health Research: A Systematic Review

BACKGROUND

Expert elicitation (EE) has been used across disciplines to estimate input parameters for computational modeling research when information is sparse or conflictual.

OBJECTIVES

We conducted a systematic review to compare EE methods used to generate model input parameters in health research.

DATA SOURCES

PubMed and Web of Science.

STUDY ELIGIBILITY

Modeling studies that reported the use of EE as the source for model input probabilities were included if they were published in English before June 2021 and reported health outcomes.

DATA ABSTRACTION AND SYNTHESIS

Studies were classified as "formal" EE methods if they explicitly reported details of their elicitation process. Those that stated use of expert opinion but provided limited information were classified as "indeterminate" methods. In both groups, we abstracted citation details, study design, modeling methodology, a description of elicited parameters, and elicitation methods. Comparisons were made between elicitation methods.

STUDY APPRAISAL

Studies that conducted a formal EE were appraised on the reporting quality of the EE. Quality appraisal was not conducted for studies of indeterminate methods.

RESULTS

The search identified 1520 articles, of which 152 were included. Of the included studies, 40 were classified as formal EE and 112 as indeterminate methods. Most studies were cost-effectiveness analyses (77.6%). Forty-seven indeterminate method studies provided no information on methods for generating estimates. Among formal EEs, the average reporting quality score was 9 out of 16.

LIMITATIONS

Elicitations on nonhealth topics and those reported in the gray literature were not included.

CONCLUSIONS

We found poor reporting of EE methods used in modeling studies, making it difficult to discern meaningful differences in approaches. Improved quality standards for EEs would improve the validity and replicability of computational models.

HIGHLIGHTS

We find extensive use of expert elicitation for the development of model input parameters, but most studies do not provide adequate details of their elicitation methods.Lack of reporting hinders greater discussion of the merits and challenges of using expert elicitation for model input parameter development.There is a need to establish expert elicitation best practices and reporting guidelines.

Vaccination for quality of life: herpes-zoster vaccines

Current vaccination policy in most high-income countries aims to counteract the decline in cell-mediated immunity to varicella zoster virus that occurs with advancing age or immunosuppression. The aim of this review was to describe the burden of illness associated with herpes zoster (HZ) and post-herpetic neuralgia (PHN) risks and their impact on the social and common life in infected people. The effectiveness/efficacy and cost effectiveness of the immunization strategy will be presented through the review of the literature relevant to the live attenuated HZ vaccine (ZLV) licensed in 2006 and the recombinant HZ vaccine (RZV). The latter has very recently been approved to protect aged people aged ≥ 50 years against HZ morbidity including its complications, and associated health-care costs. Finally, this review also provides data with respect of precautions of using and safety of ZVL and RVZ.

A Cost-Effectiveness Analysis of Vaccination for Prevention of Herpes Zoster and Related Complications: Input for National Recommendations

BACKGROUND

The U.S. Advisory Committee on Immunization Practices recently developed recommendations for use of a new recombinant zoster vaccine (RZV).

OBJECTIVE

To evaluate the cost-effectiveness of vaccination with RZV compared with zoster vaccine live (ZVL) and no vaccination, the cost-effectiveness of vaccination with RZV for persons who have previously received ZVL, and the cost-effectiveness of preferential vaccination with RZV over ZVL.

DESIGN

Simulation (state-transition) model using U.S. epidemiologic, clinical, and cost data.

DATA SOURCES

Published data.

TARGET POPULATION

Hypothetical cohort of immunocompetent U.S. adults aged 50 years or older.

TIME HORIZON

Lifetime.

PERSPECTIVE

Societal and health care sector.

INTERVENTION

Vaccination with RZV (recommended 2-dose regimen), vaccination with ZVL, and no vaccination.

OUTCOME MEASURES

The primary outcome measure was the incremental cost-effectiveness ratio (ICER).

RESULTS OF BASE-CASE ANALYSIS

For vaccination with RZV compared with no vaccination, ICERs ranged by age from $10 000 to $47 000 per quality-adjusted life-year (QALY), using a societal perspective and assuming 100% completion of the 2-dose RZV regimen. For persons aged 60 years or older, ICERs were less than $60 000 per QALY. Vaccination with ZVL was dominated by vaccination with RZV for all age groups 60 years or older.

RESULTS OF SENSITIVITY ANALYSIS

Results were most sensitive to changes in vaccine effectiveness, duration of protection, herpes zoster incidence, and probability of postherpetic neuralgia. Vaccination with RZV after previous administration of ZVL yielded an ICER of less than $60 000 per QALY for persons aged 60 years or older. In probabilistic sensitivity analyses, RZV remained the preferred strategy in at least 95% of simulations, including those with 50% completion of the second dose.

LIMITATION

Few data were available on risk for serious adverse events, adherence to the recommended 2-dose regimen, and probability of recurrent zoster.

CONCLUSION

Vaccination with RZV yields cost-effectiveness ratios lower than those for many recommended adult vaccines, including ZVL. Results are robust over a wide range of plausible values.

PRIMARY FUNDING SOURCE

Centers for Disease Control and Prevention.

Cost-Effectiveness of Herpes Zoster Vaccination: A Systematic Review

BACKGROUND

Herpes zoster (HZ) is one of the most common diseases among adults. Its reactivation is characterized by a severe and painful complication. In addition to the existing herpes zoster vaccine (ZVL), the FDA approved a new adjuvanted subunit zoster vaccine (RZV) in 2017 for use in adults aged 50 years and older. Several studies have assessed the cost-effectiveness of ZVL, many of which were conducted before the long-term vaccine  efficacy data was available in 2014.

OBJECTIVE

Our objectives were to (i) summarize and compare the cost-effectiveness analyses (CEAs) of ZVL conducted before and after 2014, (ii) summarize the CEAs of RZV, and (iii) critically assess the cost-effectiveness models and identify key parameters to consider for future CEAs of RZV.

METHODS

We searched PubMed and two other databases from inception to March 2018 for original cost-effectiveness, cost-utility, or cost-benefit analyses of HZ vaccines. Three investigators independently reviewed and assessed full-text articles after screening the titles and abstracts to determine eligibility. For all included studies, we assessed study quality using the Drummond and Jefferson's checklist and extracted study characteristics, model structure, vaccine characteristics, incidence of HZ and complications, incremental cost-effectiveness ratio, and sensitivity analyses. We summarized data by type of vaccine, year of publication, and funding sources.

RESULTS

Twenty-seven studies met eligibility criteria. All studies were from high-income countries and were of moderate-to-high or high quality. Twenty studies repeatedly used four cost-effectiveness models. The assumption on long-term efficacy of ZVL was not based on clinical trial data in > 50% of studies. Fifteen out of 25 studies concluded that ZVL was cost-effective compared with no vaccine at a vaccine price ranging between US$93 and US$236 per dose (2018 US$), 40% of which were published after 2014. All industry-funded studies favored the use of ZVL. The single study assessing RZV found it to be more effective and less costly than ZVL, and cost-effective compared with no vaccination. More studies conducted after 2014 included various efficacy endpoints for ZVL, adverse reactions, and productivity loss compared with those conducted before 2014.

CONCLUSIONS

A majority of studies of ZVL found it to be cost-effective compared with no vaccine using the authors' chosen willingness-to-pay thresholds. RZV was dominant in the single study comparing the two vaccines, but the finding needs to be confirmed with further studies in different settings. Future studies should assume vaccine efficacy in line with clinical data, account for more efficacy endpoints for ZVL, and include other HZ long-term complications, vaccine adverse reactions, and productivity loss.

Determining the optimal strategy for the live-attenuated herpes zoster vaccine in adults

The optimal strategy for the vaccinating against herpes zoster (HZ) vaccine remains unknown. Cost-effectiveness analyses provide insight to the most cost-effective age groups but results vary across studies. The optimal strategy is important given that vaccine efficacy and duration vary depending on vaccination age. Therefore, small changes from the optimal age can affect long-term outcomes and produce sub-optimal results. The objective of this research was to determine the optimal timing policy for HZ vaccination. We simulated cohorts of men and women and use stochastic dynamic programming to evaluate the decision to vaccinate or defer each year from age 50 to 100. If the decision was to defer, the cohort risked developing HZ. If HZ occurred, the cohort was subjected to cost and quality-adjusted life year (QALY) loss for a typical HZ infection (including complications) at that age. If HZ did not occur, the decision was evaluated at the next age. Then, we extend the model to consider the case in which a booster vaccine is available. A set of probabilistic sensitivity analyses were conducted to check model robustness. Results show the optimal policy for women is to vaccinate between ages 66 and 77, and for men between ages 66 and 74, assuming a willingness to pay (WTP) of $100,000 per QALY. It becomes optimal to vaccinate earlier if a booster vaccine is available, and women have a wider range of ages than men. This research is the first to examine exactly when the HZ vaccine should be administered. It is also the first study, to our knowledge, that used stochastic dynamic programming to examine the question of a second dose for any vaccine. This research provides the first simple policy on when to vaccinate and re-vaccinate against HZ.

Sponsorship Bias in Base-Case Values and Uncertainty Bounds of Health Economic Evaluations? A Systematic Review of Herpes Zoster Vaccination

BACKGROUND

New health technologies are more likely adopted when they have lower incremental cost-effectiveness ratios (ICERs) and/or when their ICER is presented with more certainty. Industry-funded (IF) health economic evaluations use often more favorable base-case values, leading to more favorable conclusions.

PURPOSE

To study whether IF health economic evaluations of varicella-zoster virus vaccination in the elderly use more favorable base-case values and account for less uncertainty than non-industry-funded (NIF) evaluations.

METHODS

DATA SOURCE

PubMed. Data extracted: funding source; incremental cost per quality-adjusted life year (QALY) gained; vaccine price; study quality score; base-case values, uncertainty ranges, and data sources for influential parameters: duration of vaccine protection, utility loss due to herpes zoster (HZ) disease, percentage of HZ patients developing postherpetic neuralgia (PHN), and duration of PHN.

DATA SYNTHESIS

qualitative comparisons; Fisher exact test for differences in study quality score and 1-sided Mann-Whitney U tests for differences in base-case values and uncertainty ranges.

RESULTS

Despite using the same data sources, IF studies ( n = 10) assume a longer duration of vaccine protection ( U = 56, P = 0.03), have a higher percentage of HZ patients developing PHN ( U = 22/33, P = 0.02/0.03 for ages 60-64/65-69), and tend to use higher HZ utility loss than NIF studies ( n = 11) for their baseline. IF studies show lower ICERs given similar or even higher vaccine prices than NIF studies, consider less uncertainty around the duration of vaccine protection ( U = 8, P < 0.001), and tend to use less uncertainty around the duration of PHN. Yet their quality has been rated equally well, using current standard quality rating tools.

CONCLUSION

Researchers and decision makers should be aware of potential sponsorship bias in health economic evaluations, especially in the way source data are used to specify base-case values and uncertainty ranges.

Herpes zoster vaccine: A health economic evaluation for Switzerland

Herpes zoster (HZ) or “shingles” results from a reactivation of the varicella zoster virus (VZV) acquired during primary infection (chickenpox) and surviving in the dorsal root ganglia. In about 20% of cases, a complication occurs, known as post-herpetic neuralgia (PHN). A live attenuated vaccine against VZV is available for the prevention of HZ and subsequent PHN. The present study aims to update an earlier evaluation estimating the cost-effectiveness of the HZ vaccine from a Swiss third party payer perspective. It takes into account updated vaccine prices, a different age cohort, latest clinical data and burden of illness data. A Markov model was developed to simulate the lifetime consequences of vaccinating 15% of the Swiss population aged 65–79 y. Information from sentinel data, official statistics and published literature were used. Endpoints assessed were number of HZ and PHN cases, quality-adjusted life years (QALYs), costs of hospitalizations, consultations and prescriptions. Based on a vaccine price of CHF 162, the vaccination strategy accrued additional costs of CHF 17,720,087 and gained 594 QALYs. The incremental cost-effectiveness ratio (ICER) was CHF 29,814 per QALY gained. Sensitivity analyses showed that the results were most sensitive to epidemiological inputs, utility values, discount rates, duration of vaccine efficacy, and vaccine price. Probabilistic sensitivity analyses indicated a more than 99% chance that the ICER was below 40,000 CHF per QALY. Findings were in line with existing cost-effectiveness analyses of HZ vaccination. This updated study supports the value of an HZ vaccination strategy targeting the Swiss population aged 65–79 y.

COST-EFFECTIVENESS ANALYSIS OF HERPES ZOSTER VACCINATION IN ITALIAN ELDERLY PERSONS

Objectives:Herpes zoster (HZ) is characterized by a painful skin rash. Its main complication is postherpetic neuralgia (PHN), pain persisting or occurring after the rash onset. HZ treatment aims to reduce acute pain, impede the onset complications, and disease progression. The aim of this study was to assess the cost-effectiveness of HZ vaccination compared with no vaccination strategy, within the Italian context.

Methods:The natural history of HZ and PHN was mapped through a Markov model with lifetime horizon. A population of patients aged between 60 and 79 years was hypothesized. Third party payer (Italian National Health Service, I-NHS) and societal perspectives were adopted. Data were derived from literature.

Results and Conclusions:The incremental cost-effectiveness ratio of the vaccination equaled EUR 11,943 per quality-adjusted life-year (QALY) under the I-NHS perspective and EUR 11,248 per QALY under the societal perspective. Considering a cost-effectiveness threshold of EUR 30,000/QALY, the multi-way sensitivity analysis showed that vaccination is cost-effective regardless of the perspective adopted, in 99 percent of simulations.

The use of Zostavax in Spain: the economic case for vaccination of individuals aged 50 years and older

Background Population aging brings up a number of health issues, one of which is an increased incidence of herpes zoster (HZ) and its complication, post-herpetic neuralgia (PHN). Zostavax vaccine has recently become available to prevent HZ and PHN. This study evaluates the cost-effectiveness of vaccination against HZ in Spain considering a vaccination of the population aged 50 years and older and comparing this to the current situation where no vaccination is being administered. Methods An existing, validated, and published economic model was adapted to Spain using relevant local input parameters and costs from 2013. Results Vaccinating 30% of the Spanish population aged 50 years and older resulted in €16,577/QALY gained, €2025/HZ case avoided, and €5594/PHN case avoided under the third-party payer perspective. From a societal perspective, the ICERs increased by 6%, due to the higher price of the vaccine. The number needed to vaccinate to prevent one case was 20 for HZ, and 63 for PHN3. Sensitivity analyses showed that the model was most sensitive to the HZ and PHN epidemiological data, the health state utilities values, and vaccine price used. Conclusion Considering an acceptable range of cost-effectiveness of €30,000-€50,000 per QALY gained, vaccination of the 50+ population in Spain against HZ with a new vaccine, Zostavax, is cost-effective and makes good use of the valuable healthcare budget.

Methods for Health Economic Evaluation of Vaccines and Immunization Decision Frameworks: A Consensus Framework from a European Vaccine Economics Community

BACKGROUND

Incremental cost-effectiveness and cost-utility analyses [health economic evaluations (HEEs)] of vaccines are routinely considered in decision making on immunization in various industrialized countries. While guidelines advocating more standardization of such HEEs (mainly for curative drugs) exist, several immunization-specific aspects (e.g. indirect effects or discounting approach) are still a subject of debate within the scientific community.

OBJECTIVE

The objective of this study was to develop a consensus framework for HEEs of vaccines to support the development of national guidelines in Europe.

METHODS

A systematic literature review was conducted to identify prevailing issues related to HEEs of vaccines. Furthermore, European experts in the field of health economics and immunization decision making were nominated and asked to select relevant aspects for discussion. Based on this, a workshop was held with these experts. Aspects on 'mathematical modelling', 'health economics' and 'decision making' were debated in group-work sessions (GWS) to formulate recommendations and/or--if applicable--to state 'pros' and 'contras'.

RESULTS

A total of 13 different aspects were identified for modelling and HEE: model selection, time horizon of models, natural disease history, measures of vaccine-induced protection, duration of vaccine-induced protection, indirect effects apart from herd protection, target population, model calibration and validation, handling uncertainty, discounting, health-related quality of life, cost components, and perspectives. For decision making, there were four aspects regarding the purpose and the integration of HEEs of vaccines in decision making as well as the variation of parameters within uncertainty analyses and the reporting of results from HEEs. For each aspect, background information and an expert consensus were formulated.

CONCLUSIONS

There was consensus that when HEEs are used to prioritize healthcare funding, this should be done in a consistent way across all interventions, including vaccines. However, proper evaluation of vaccines implies using tools that are not commonly used for therapeutic drugs. Due to the complexity of and uncertainties around vaccination, transparency in the documentation of HEEs and during subsequent decision making is essential.

Cost-effectiveness analysis of a vaccination program for the prevention of herpes zoster and post-herpetic neuralgia in adults aged 50 and over in Germany

Herpes zoster (HZ; shingles) is a common viral disease that affects the nerves and surrounding skin causing a painful dermatomal rash and leading to debilitating complications such as, mainly, post-herpetic neuralgia (PHN). Currently, there is no effective treatment for HZ and PHN. The objective of this study was to assess the cost-effectiveness of a HZ vaccination program in Germany. An existing Markov Model was adapted to the German healthcare setting to compare a vaccination policy to no vaccination on a lifetime time-horizon, considering 2 scenarios: vaccinating people starting at the age of 50 or at the age of 60 years, from the perspective of the statutory health insurance (SHI) and the societal perspective. According to the perspective, vaccinating 20% of the 60+ German population resulted in 162,713 to 186,732 HZ and 31,657 to 35,793 PHN cases avoided. Corresponding incremental cost-effectiveness ratios (ICER) were 39,306 €/QALY from the SHI perspective and 37,417 €/QALY from a societal perspective. Results for the 50+ German population ranged from 336,468 to 394,575 HZ and from 48,637 to 56,087 PHN cases avoided from the societal perspective. Corresponding ICER were 39,782 €/QALY from a SHI perspective and 32,848 €/QALY from a societal perspective. Sensitivity analyses showed that results are mainly impacted by discount rates, utility values and use of alternative epidemiological data.The model indicated that a HZ vaccination policy in Germany leads to significant public health benefits and could be a cost-effective intervention. The results were robust and consistent with local and international existing literature.

[Vaccines against Herpes zoster: Effectiveness, safety, and cost/benefit ratio]

CONTEXT

A vaccination against herpes zoster and its complication is available in France since June 2015. Its exact benefit for public health is still controversial and its level of protection is not optimal. All those reasons seem to suggest a low acceptation rate from general practitioners.

OBJECTIVE

To evaluate the effectiveness, the safety, and the cost/benefit ratio of the vaccination against herpes zoster in people aged 50 year or over.

DOCUMENTARY SOURCE

Systematic review in Medline and PubMed with research by key words: "herpes zoster vaccine", "zoster vaccine" and "post herpetic neuralgia vaccine".

SELECTION OF STUDIES

Randomized and observational studies published in English and French language have been selected by two readers.

RESULTS

On 1886 articles identified, 62 studies were included in this systematic review of which 21 randomized trials, 21 observational studies, and 17 medico-economic studies concerned the unadjuvanted vaccine. Considered studies showed an effectiveness of 50% against herpes zoster and 60% on post-herpetic neuralgia incidence of the unadjuvanted vaccine. Five randomized controlled studies were identified for the adjuvanted vaccine. The overall effectiveness of this vaccine was > 90% whatever the age of subjects including those over age 70 and 80. The medico-economic studies conducted in many countries have shown that vaccine policies were beneficial in individuals aged 60 years or over.

LIMITATION OF THE WORK

Most of data of effectiveness, and tolerance result from 2 large controlled studies only (SPS and ZEST) for the unadjuvanted vaccine and only one for the adjuvanted vaccine.

CONCLUSION

Despite controversy and few uncertainties, the vaccine significantly reduces herpes zoster and its complication incidence. In terms of public health objectives, it reduces the burden of the disease and has a positive medico-economic impact. Preliminary data concerning the adjuvanted vaccine, whilst very promising, are still too limited. Up to now, no group of people with particularly high risk of herpes zoster-related complication who will beneficiate the most of the vaccination has been identified yet and only an age criteria has been considered for the recommendation.

Review of the Persistence of Herpes Zoster Vaccine Efficacy in Clinical Trials

PURPOSE

The live attenuated herpes zoster vaccine(*) was approved for the prevention of shingles in 2006. Initial Phase III clinical trials proved vaccine efficacy persisted during the study duration; however, assessment of long-term efficacy required additional studies. This article reviews efficacy data for the zoster vaccine that have been published since 2004. It focuses on studies assessing declining vaccine efficacy.

METHODS

MEDLINE, EMBASE, CENTRAL, and CINAHL databases were searched for zoster vaccine efficacy trials. Randomized controlled trials published from 2004 to 2015 were included in the review.

FINDINGS

Six studies were included in the review. The zoster vaccine reduced the risk of herpes zoster by 51.3% to 72.4% in 2 Phase III trials. Primary and other analyses showed the vaccine was effective at reducing the burden of illness (61.1%), postherpetic neuralgia (66.5%), disease interference on functional status (66.2%), and disease impact on health-related quality of life (55%) compared with placebo. Surveillance studies showed a decrease in vaccine efficacy for reducing the incidence of herpes zoster during follow-up years 3.3 to 7.8 (39.6% relative reduction) and 4.7 to 11.6 (21.1% relative reduction).

IMPLICATIONS

Initial zoster vaccine efficacy is significant, but declines in post-vaccination years 3 to 11. This raises the question about the need for possible revaccination with the zoster vaccine. Clinicians should consider the declining efficacy when administering the zoster vaccine to patients. Future studies will need to address the impact of the varicella vaccine on the incidence of shingles and whether this impacts the efficacy of the zoster vaccine.

Herpes zoster epidemiology, management, and disease and economic burden in Europe: a multidisciplinary perspective

Herpes zoster (HZ) is primarily a disease of nerve tissue but the acute and longer-term manifestations require multidisciplinary knowledge and involvement in their management. Complications may be dermatological (e.g. secondary bacterial infection), neurological (e.g. long-term pain, segmental paresis, stroke), ophthalmological (e.g. keratitis, iridocyclitis, secondary glaucoma) or visceral (e.g. pneumonia, hepatitis). The age-related increased incidence of HZ and its complications is thought to be a result of the decline in cell-mediated immunity (immunosenescence), higher incidence of comorbidities with age and social-environmental changes. Individuals who are immunocompromised as a result of disease or therapy are also at increased risk, independent of age. HZ and its complications (particularly postherpetic neuralgia) create a significant burden for the patient, carers, healthcare systems and employers. Prevention and treatment of HZ complications remain a therapeutic challenge despite recent advances. This is an overview of the multidisciplinary implications and management of HZ in which the potential contribution of vaccination to reducing the incidence HZ and its complications are also discussed.

Systematic review of models assessing the economic value of routine varicella and herpes zoster vaccination in high-income countries

BACKGROUND

A systematic review was conducted to assess the cost-effectiveness of routine varicella and herpes zoster (HZ) vaccination in high-income countries estimated by modelling studies.

METHODS

A PubMed search was performed to identify relevant studies published before October 2013. Studies were included in the review if they (i) evaluated the cost-effectiveness of routine childhood or adolescent varicella vaccination and/or HZ vaccination targeting the elderly, and if they (ii) reported results for high-income countries.

RESULTS

A total of 38 model-based studies were identified that fulfilled the inclusion criteria. Routine childhood or adolescent varicella vaccination was cost-effective or cost-saving from a payer perspective and always cost-saving from a societal perspective when ignoring its potential impact on HZ incidence due to reduced or absent exogenous boosting. The inclusion of the potential impact of childhood varicella vaccination on HZ led to net quality-adjusted life-year (QALY) losses or incremental cost-effectiveness ratios exceeding commonly accepted thresholds. Additional HZ vaccination could partially mitigate this effect. Studies focusing only on the evaluation of HZ vaccination reported a wide range of results depending on the selected target age-group and the vaccine price, but most found HZ vaccination to be a cost-effective or marginally cost-effective intervention. Cost-effectiveness of HZ vaccination was strongly dependent on the age at vaccination, the price of the vaccine, the assumed duration of protection and the applied cost per QALY threshold.

CONCLUSIONS

While HZ vaccination is mostly considered cost-effective, cost-effectiveness of varicella vaccination primarily depends on the in- or exclusion of exogenous boosting in the model. As a consequence, clarification on the role of exogenous boosting is crucial for decision-making regarding varicella vaccination.

The humanistic, economic and societal burden of herpes zoster in Europe: a critical review

BACKGROUND

Herpes zoster (HZ) or "shingles" is common in persons aged 50 years or over. HZ is characterised by a painful dermatological rash which typically resolves in approximately one month. Persistent pain for months or years after rash onset, however, is a common complication of HZ; referred to as post-herpetic neuralgia (PHN). Both HZ and PHN have a significant impact on patients' lives, with considerable implications for healthcare systems and wider society. The aim of the present review is to provide comprehensive documentation and critical appraisal of published data concerning the humanistic, economic and societal burden of HZ in Europe.

METHODS

Systematic literature searches were conducted in Medline, EMBASE, PsycINFO, EconLit, HEED and CRD databases. Searches were conducted in July 2014 and restricted to articles published in the past 20 years. Articles were selected for full review by two independent researchers in accordance with predefined eligibility criteria.

RESULTS

From a review of 1619 abstracts, 53 eligible articles, were identified which reported data concerning healthcare resource use (n = 38), direct costs (n = 20), indirect costs (n = 16), total costs (n = 10) and impact on health-related quality of life (HRQoL) (n = 21). Findings highlight that PHN is associated with greater impairments in HRQoL and higher costs of management than HZ. For both HZ and PHN, pain severity is a significant predictor of impact on individuals, healthcare systems and society. While the incidence of HZ and PHN increase with age, age does not appear to be a key driver of overall costs for HZ and PHN. Specifically, while direct costs (e.g. GP, specialists, medications, hospitalisations) tend to be higher for older patients, indirect costs (e.g. work time missed) are higher for younger patients.

CONCLUSIONS

Available evidence highlights that HZ and PHN result in significant humanistic and economic burden for patients, healthcare systems and wider societies. A tendency to focus upon healthcare resource use and the direct costs of management at the expense of other impacts (e.g. informal caregivers and formal social care) may result in an underestimation of the true burden of HZ and PHN.

How and why researchers use the number needed to vaccinate to inform decision making--a systematic review

BACKGROUND

The number needed to vaccinate (NNV) is a measure that has been widely used in the scientific literature to draw conclusions about the usefulness and cost-effectiveness of various immunization programmes. The main objective of this review is to examine how and why the NNV has been used and reported in the published literature.

METHODS

Electronic databases were searched and records were screened against the eligibility criteria by two independent authors. We included papers that reported and interpreted NNV.

RESULTS

We identified 27 studies, the designs including observational studies, economic analyses, systematic reviews, and commentaries. The NNV has been used in the literature to describe three main themes: potential benefits of vaccination programmes, cost-effectiveness, and economic analyses, and modelling studies to compare different vaccination strategies.

CONCLUSIONS

NNV has been used in a wide variety of ways in the literature, yet there are no defined thresholds for what is a favourable NNV. Furthermore, the generalizability of the NNV is usually limited. Further work is required to determine the most appropriate use of this measure.

Is herpes zoster vaccination likely to be cost-effective in Canada?

OBJECTIVES

To synthesize the current literature detailing the cost-effectiveness of the herpes zoster (HZ) vaccine, and to provide Canadian policy-makers with cost-effectiveness measurements in a Canadian context.

METHODS

This article builds on an existing systematic review of the HZ vaccine that offers a quality assessment of 11 recent articles. We first replicated this study, and then two assessors reviewed the articles and extracted information on vaccine effectiveness, cost of HZ, other modelling assumptions and QALY estimates. Then we transformed the results into a format useful for Canadian policy decisions. Results expressed in different currencies from different years were converted into 2012 Canadian dollars using Bank of Canada exchange rates and a Consumer Price Index deflator. Modelling assumptions that varied between studies were synthesized. We tabled the results for comparability.

SYNTHESIS

The Szucs systematic review presented a thorough methodological assessment of the relevant literature. However, the various studies presented results in a variety of currencies, and based their analyses on disparate methodological assumptions. Most of the current literature uses Markov chain models to estimate HZ prevalence. Cost assumptions, discount rate assumptions, assumptions about vaccine efficacy and waning and epidemiological assumptions drove variation in the outcomes. This article transforms the results into a table easily understood by policy-makers.

CONCLUSION

The majority of the current literature shows that HZ vaccination is cost-effective at the price of $100,000 per QALY. Few studies showed that vaccination cost-effectiveness was higher than this threshold, and only under conservative assumptions. Cost-effectiveness was sensitive to vaccine price and discount rate.

Cost-effectiveness of vaccination against herpes zoster and postherpetic neuralgia: a critical review

OBJECTIVE

The objective of this study was to systematically review cost-effectiveness studies of vaccination against herpes zoster (HZ) and postherpetic neuralgia (PHN).

METHODS

We searched MEDLINE and EMBASE databases for eligible studies published prior to November 2013. We extracted information regarding model structure, model input parameters, and study results. We compared the results across studies by projecting the health and economic impacts of vaccinating one million adults over their lifetimes.

RESULTS

We identified 15 cost-effectiveness studies performed in North America and Europe. Results ranged from approximately US$10,000 to more than US$100,000 per quality-adjusted life years (QALY) gained. Most studies in Europe concluded that zoster vaccination is likely to be cost-effective. Differences in results among studies are largely due to differing assumptions regarding duration of vaccine protection and a loss in quality of life associated with HZ and to a larger extent, PHN. Moreover, vaccine efficacy against PHN, age at vaccination, and vaccine cost strongly influenced the results in sensitivity analyses.

CONCLUSION

Most studies included in this review shows that vaccination against HZ is likely to be cost-effective. Future research addressing key model parameters and cost-effectiveness studies in other parts of the world are needed.

Cost-effectiveness of vaccination against herpes zoster

Herpes zoster (HZ) is a common disease among elderly, which may develop into a severe pain syndrome labeled postherpetic neuralgia (PHN). A live-attenuated varicella zoster virus vaccine has been shown to be effective in reducing the incidence and burden of illness of HZ and PHN, providing the opportunity to prevent significant health-related and financial consequences of HZ. In this review, we summarize the available literature on cost-effectiveness of HZ vaccination and discuss critical parameters for cost-effectiveness results. A search in PubMed and EMBASE was performed to identify full cost-effectiveness studies published before April 2013. Fourteen cost-effectiveness studies were included, all performed in western countries. All studies evaluated cost-effectiveness among elderly above 50 years and used costs per quality-adjusted life year (QALY) gained as primary outcome. The vast majority of studies showed vaccination of 60- to 75-year-old individuals to be cost-effective, when duration of vaccine efficacy was longer than 10 years. Duration of vaccine efficacy, vaccine price, HZ incidence, HZ incidence and discount rates were influential to the incremental cost-effectiveness ratio (ICER). HZ vaccination may be a worthwhile intervention from a cost-effectiveness point of view. More extensive reporting on methodology and more detailed results of sensitivity analyses would be desirable to address uncertainty and to guarantee optimal comparability between studies, for example regarding model structure, discounting, vaccine characteristics and loss of quality of life due to HZ and PHN.

Epidemiology and cost of herpes zoster and postherpetic neuralgia in Germany

After acquiring a varicella virus infection, the virus can reactivate and cause herpes zoster (HZ)--a painful skin rash. A complication of HZ is long-term persistence of pain after the rash has resolved (so-called postherpetic neuralgia, PHN). We aimed to describe the epidemiology of HZ/PHN and to estimate HZ/PHN-related costs in the German statutory health insurance (SHI) system (~85% of the total population). Treatment data of one large SHI was utilized, containing data on approximately 240,000 insured and their utilisation of services in 2004-2009. Identification of HZ- and PHN-cases was performed based on 'International Statistical Classification of Diseases' and specific medications using a control-group design. Incidences per 1,000 person-years (PY) and cost-of-illness for 1 year following HZ-onset considering the payer and societal perspective were calculated. All amounts were inflated to 2010 Euros. Population-figures were standardised and extrapolated to the total SHI-population in Germany in 2010. A mean annual incidence of 5.79 HZ-cases per 1,000 PY was observed, translating into an estimated 403,625 HZ-cases per year in the total SHI-population. Approximately 5% of HZ-cases developed PHN. One HZ-case caused on average euro 210 and euro 376 of costs from the payer and societal perspective, respectively. The development of PHN generated additional costs of euro 1,123 (euro 1,645 societal perspective). Total annual HZ/PHN-related costs were estimated at euro 182 million (euro 105 million) to society (payer). HZ and PHN place a considerable burden on the German SHI-system. Since HZ-vaccines will soon be available, a health-economic evaluation of these vaccines should be conducted.

Health economic evaluation of vaccination strategies for the prevention of herpes zoster and postherpetic neuralgia in Germany

BACKGROUND

Herpes zoster (HZ) is a self-limiting painful skin rash affecting mostly individuals from 50 years of age. The main complication is postherpetic neuralgia (PHN), a long-lasting pain after rash has resolved. A HZ-vaccine has recently been licensed in Europe for individuals older than 50 years. To support an informed decision-making for a potential vaccination recommendation, we conducted a health economic evaluation to identify the most cost-effective vaccination strategy.

METHODS

We developed a static Markov-cohort model, which compared a vaccine-scenario with no vaccination. The cohort entering the model was 50 years of age, vaccinated at age 60, and stayed over life-time in the model. Transition probabilities were based on HZ/PHN-epidemiology and demographic data from Germany, as well as vaccine efficacy (VE) data from clinical trials. Costs for vaccination and HZ/PHN-treatment (in Euros; 2010), as well as outcomes were discounted equally with 3% p.a. We accounted results from both, payer and societal perspective. We calculated benefit-cost-ratio (BCR), number-needed-to-vaccinate (NNV), and incremental cost-effectiveness ratios (ICERs) for costs per HZ-case avoided, per PHN-case avoided, and per quality-adjusted life-year (QALY) gained. Different target age-groups were compared to identify the most cost-effective vaccination strategy. Base-case-analysis as well as structural, descriptive-, and probabilistic-sensitivity-analyses (DSA, PSA) were performed.

RESULTS

When vaccinating 20% of a cohort of 1 million 50 year old individuals at the age of 60 years, approximately 20,000 HZ-cases will be avoided over life-time. The NNV to avoid one HZ (PHN)-case was 10 (144). However, with a BCR of 0.34 this vaccination-strategy did not save costs. The base-case-analysis yielded an ICER of 1,419 (20,809) Euros per avoided HZ (PHN)-case and 28,146 Euros per QALY gained. Vaccination at the age of 60 was identified in most (sensitivity) analyses to be the most cost-effective vaccination strategy. In DSA, vaccine price and VE were shown to be the most critical input-data.

CONCLUSIONS

According to our evaluation, HZ-vaccination is expected to avoid HZ/PHN-cases and gain QALYs to higher costs. However, the vaccine price had the highest impact on the ICERs. Among different scenarios, targeting individuals aged 60 years seems to represent the most cost-effective vaccination-strategy.

Vaccination against herpes zoster and postherpetic neuralgia in France: a cost-effectiveness analysis

This study assesses the cost-effectiveness of vaccination against herpes zoster (HZ) and postherpetic neuralgia in France, using a published Markov model. The cost-effectiveness of vaccinating individuals aged from 65 years or between 70 and 79 years was evaluated over their lifetime, from a third-party payer perspective. French-specific data were combined with results from clinical studies and international quality-of-life-based (EuroQol five-dimension questionnaire) utilities from the literature. HZ vaccination was highly cost effective in both populations. Incremental cost-effective ratios were estimated between €9513 and 12,304 per quality-adjusted life year gained, corresponding to €2240-2651 per HZ case avoided and €3539-4395 per postherpetic neuralgia case avoided. In addition to epidemiological and clinical evidence, economic evidence also supports the implementation of HZ vaccination in France.

A systematic review of the cost effectiveness of herpes zoster vaccination

BACKGROUND

The varicella zoster virus (VZV) can cause two infections: chickenpox or herpes zoster (HZ). Whereas chickenpox infections are normally mild but common among children, HZ infections are common among elderly people and can give rise to post-herpetic neuralgia (PHN), a severe and painful complication.

OBJECTIVES

This review aimed to summarize the literature available on the cost effectiveness of HZ vaccination and to summarize key issues for decision makers to consider when deciding on the reimbursement of HZ vaccination.

METHODS

We conducted a literature search of the databases PubMed and EMBASE using EndNote X4 from Thomson Reuters. The following combinations of keywords were used: 'herpes zoster vaccine' AND 'cost(-)effectiveness' or AND 'economic evaluation', 'herpes zoster vaccination' AND 'cost(-)effectiveness' or AND 'economic evaluation', 'varicella zoster vaccine' AND 'cost(-)effectiveness' or AND 'economic evaluation', and 'varicella zoster vaccination' AND 'cost(-)effectiveness' or AND 'economic evaluation'.

RESULTS

A total of 11 studies were identified and included. Cost-effectiveness analyses of varicella zoster vaccination were excluded. The quality of the included studies ranged from 'moderate' to 'moderate to good' according to the British Medical Journal guidelines of Drummond and Jefferson and the Quality of Health Economic Studies (QHES) score of Ofman et al. Most studies evaluated the cost effectiveness of universal HZ vaccination in adults aged 50 years or 60 years and older. Data sources and model assumptions regarding epidemiology, utility estimates and costs varied between studies. All studies calculated costs per QALY, which allows comparing costs of interventions in different diseases. The costs per QALY gained and the incremental cost-effectiveness ratio (ICER) differed between studies depending on the age at vaccination, duration of vaccine efficacy, cost of vaccine course and economic perspective. All but one of the studies concluded that most vaccination scenarios are cost effective and the vaccination of specific subgroups such as the older age group is most cost effective.

CONCLUSIONS

Model input parameters such as age at vaccination, vaccine costs, HZ incidence, PHN length and duration of vaccine efficacy had a great impact on the estimated cost effectiveness of HZ vaccination. To compare the results of different cost-effectiveness studies of HZ vaccination, uniform methods should be used and the most important input parameters used for the different models should be critically assessed.

Vaccination against herpes zoster in developed countries: state of the evidence

Although progress has been made in the treatment of herpes zoster (HZ) and postherpetic neuralgia (PHN), available therapeutic options are only partially effective. Given evidence that a live-attenuated varicella-zoster-virus vaccine is effective at reducing the incidence of HZ, PHN and the burden of illness, policymakers and clinicians are being asked to make recommendations regarding the use of the zoster vaccine. In this report, we summarize the evidence regarding the: (1) burden of illness; (2) vaccine efficacy and safety; and (3) cost-effectiveness of vaccination, to assist evidence-based policy making and guide clinicians in their recommendations. First, there is general agreement that the overall burden of illness associated with HZ and PHN is substantial. Second, the safety and efficacy of the zoster vaccine at reducing the burden of illness due to HZ and the incidence of PHN have been clearly demonstrated in large placebo-controlled trials. However, uncertainty remains about the vaccine's duration of protection. Third, vaccination against HZ is likely to be cost-effective when the vaccine is given at approximately 65 y of age, if vaccine duration is longer than 10 y.

Post-herpetic neuralgia

Background

In spite of the large body of evidence available in the literature, definition and treatment of Post-Herpetic Neuralgia (PHN) are still lacking a consistent and universally recognized standardization. Furthermore, many issues concerning diagnosis, prediction and prevention of PHN need to be clarified in view of recent contributions.

Objectives

To assess whether PHN may be better defined, predicted, treated and prevented in light of recent data, and whether available alternative or adjunctive therapies may improve pain relief in treatment recalcitrant PHN.

Methods

Systematic reviews, meta-analyses, randomized controlled trials, cohort studies and protocols were searched; the search sources included PubMed, Cochrane Library, NICE, and DARE. More than 130 papers were selected and evaluated.

Results

Diagnosis of PHN is essentially clinical, but it can be improved by resorting to the many tools available, including some practical and accessible questionnaires. Prediction of PHN can be now much more accurate, taking into consideration a few well validated clinical and anamnestic variables. Treatment of PHN is presently based on a well characterized array of drugs and drug associations, including, among others, tricyclic antidepressants, gabapentinoids, opioids and many topical formulations. It is still unsatisfactory, however, in a substantial proportion of patients, especially those with many comorbidities and intense pain at herpes zoster (HZ) presentation, so that this frequent complication of HZ still strongly impacts on the quality of life of affected patients.

Conclusion

Further efforts are needed to improve the management of PHN. Potentially relevant interventions may include early antiviral therapy of acute HZ, prevention of HZ by adult vaccination, as well as new therapeutic approaches for patients experiencing PHN.

The health and economic burden of chickenpox and herpes zoster in Belgium

Varicella-zoster virus causes chickenpox (CP) and after reactivation herpes zoster (HZ). Vaccines are available against both diseases warranting an assessment of the pre-vaccination burden of disease. We collected data from relevant Belgian databases and performed five surveys of CP and HZ patients. The rates at which a general practitioner is visited at least once for CP and HZ are 346 and 378/100 000 person-years, respectively. The average CP and HZ hospitalization rates are 5·3 and 14·2/100 000 person-years respectively. The direct medical cost for HZ is about twice as large as the direct medical cost for CP. The quality-adjusted life years lost for ambulatory CP patients consulting a physician is more than double that of those not consulting a physician (0·010 vs. 0·004). In conclusion, both diseases cause a substantial burden in Belgium.

Cost-effectiveness of vaccination against herpes zoster in adults aged over 60 years in Belgium

AIM

To assess the cost-effectiveness of vaccinating all or subgroups of adults aged 60 to 85 years against herpes zoster.

METHODS

A deterministic compartmental static model was developed (in freeware R), in which cohorts can acquire herpes zoster according to their age in years. Surveys and database analyses were conducted to obtain as much as possible Belgian age-specific estimates for input parameters. Direct costs and Quality-Adjusted Life-Year (QALY) losses were estimated as a function of standardised Severity Of Illness (SOI) scores (i.e. as a function of the duration and severity of herpes zoster disease).

RESULTS

Uncertainty about the average SOI score for a person with herpes zoster, the duration of protection from the vaccine, and the population that can benefit from the vaccine, exerts a major impact on the results: under assumptions least in favour of vaccination, vaccination is not cost-effective (i.e. incremental cost per QALY gained >€48,000 for all ages considered) at the expected vaccine price of €90 per dose. At the same price, but under assumptions most in favour of vaccination, vaccination is found to be cost-effective (i.e. incremental cost per QALY gained <€5500 for all ages considered). Vaccination of age cohort 60 seems more cost-effective than vaccination of any older age cohort in Belgium.

DISCUSSION

If the vaccine price per dose drops to €45, HZ vaccination of adults aged 60-64 years is likely to be cost-effective in Belgium, even under assumptions least in favour of vaccination. Unlike previous studies, our analysis acknowledged major methodological and model uncertainties simultaneously and presented outcomes for 26 different target ages at which vaccination can be considered (ages 60-85).

Estimating the age-specific duration of herpes zoster vaccine protection: a matter of model choice?

INTRODUCTION

The estimation of herpes zoster (HZ) vaccine efficacy by time since vaccination and age at vaccination is crucial to assess the effectiveness and cost-effectiveness of HZ vaccination. Published estimates for the duration of protection from the vaccine diverge substantially, although based on data from the same trial for a follow-up period of 5 years. Different models were used to obtain these estimates, but it is unclear which of these models is most appropriate (if any). Only one study estimated vaccine efficacy by age at vaccination and time since vaccination combined. Recently, data became available from the same trial for a follow-up period of 7 years.

AIM AND METHODS

We aim to elaborate on estimating HZ vaccine efficacy (1) by estimating it as a function of time since vaccination and age at vaccination, (2) by comparing the fits of a range of models, and (3) by fitting these models on data for a follow-up period of 5 and 7 years.

RESULTS

Although the models' fit to data are very comparable, they differ substantially in how they estimate vaccine efficacy to change as a function of time since vaccination and age at vaccination.

DISCUSSION

An accurate estimation of HZ vaccine efficacy by time since vaccination and age at vaccination is hampered by the lack of insight in the biological processes underlying HZ vaccine protection, and by the fact that such data are currently not available in sufficient detail. Uncertainty about the choice of model to estimate this important parameter should be acknowledged in cost-effectiveness analyses.