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

Return on Investment (ROI) of Three Vaccination Programmes in Italy: HPV at 12 Years, Herpes Zoster in Adults, and Influenza in the Elderly

The calculation of the return on investment (ROI) allows the estimation of the opportunity cost of a series of interventions and can therefore help to make allocative choices. The objective of this study is to estimate the ROI of three vaccinations (HPV for adolescents, HZ for adults, and influenza for the elderly) in the Italian context, considering the impact of increasing vaccination coverage based on target objectives of the National Immunization Plan (PNPV) 2017-2019 and accounting for different eligibility criteria of each vaccination. Three separate static cohort models were constructed, including the eligible population for these vaccinations on the basis of the PNPV 2017-2019 and following this population until death (lifetime horizon) or until vaccination waning. Each model compares the level of investment at current vaccine coverage rates (current VCRs scenario) with that of optimal NIP target VCRs with a non-vaccination scenario. The ROI for HPV vaccination was the highest among the programs compared and was always above 1 (range: 1.4-3.58), while lower values were estimated for influenza vaccination in the elderly (range 0.48-0.53) and for vaccination against HZ (range: 0.09-0.27). Our analysis showed that a significant proportion of savings generated by vaccination programs occurred outside the NHS perspective and might often not be estimated with other forms of economic evaluation.

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 potential public health impact of Herpes Zoster vaccination in the 65 years of age cohort in Italy

Herpes Zoster (HZ) presents a considerable public health burden in Italy among people aged ≥50 years. This study aimed to assess the clinical and economic impact of HZ vaccination in the 65 years of age (YOA) cohort in Italy, by comparing the new Adjuvanted Recombinant Zoster Vaccine (RZV) with the currently available Zoster Vaccine Live (ZVL). A static Markov model was developed to follow all 65 YOA subjects from the year of vaccination over their lifetime by comparing three different HZ vaccination strategies: no vaccination, vaccination with ZVL and vaccination with RZV. In the base-case scenario, three 65 YOA cohorts were assumed to be vaccinated within three years, with a vaccine coverage rate of 20%, 35% and 50% at Year 1, 2 and 3 respectively, as recommended by the National Immunization Plan. The three 65 YOA Italian cohorts accounted altogether for 2,290,340 individuals. Of these, it was assumed that 564,178 subjects could be vaccinated with either RZV or ZVL in three years. The vaccination with RZV could prevent an additional total number of 35,834 HZ and 8,131 postherpetic neuralgia (PHN) cases over ZVL, leading to additional total savings of €12.4 million for the national healthcare and social systems. The introduction of RZV can be expected to have higher impact on the burden of HZ disease in the 65 YOA cohort in Italy. The avoided HZ and PHN cases can lead to an associated reduction in economic burden to the healthcare and social systems.

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.

The Economic Burden and Impact on Quality of Life of Herpes Zoster and Postherpetic Neuralgia in Individuals Aged 50 Years or Older in Italy

Background

To estimate the health care resource utilization, costs, and impact on quality of life (QoL) of herpes zoster (HZ) and postherpetic neuralgia (PHN) in adults aged ≥50 years in Italy.

Methods

This was a prospective, observational, multicenter, community physician–based surveillance study (NCT01772160) in Italy. Health-related QoL data were collected using the EuroQoL-5 Dimension (EQ-5D) and Zoster Brief Pain Inventory (ZBPI) questionnaires. Both questionnaires were assessed at days 0 (HZ rash onset), 15, 30, 60, and 90 for all patients, and monthly thereafter for patients who developed PHN. Resource utilization was recorded for 3 months post–HZ onset and 9 months for PHN patients. Costs from both payer and societal perspectives were estimated and were composed of direct medical costs (general practitioner/specialist visits, procedures, hospitalizations, medications), work loss by patient/caregiver, and transport costs.

Results

A total of 391 patients with HZ were included, of whom 40 developed PHN. The mean ZBPI worst pain score was 5.7 at day 0, reducing to 2.6 at day 30 and 0.7 by day 90. Patients with PHN had a mean worst pain score of 5.7 at day 90. We estimated an overall disutility associated with HZ of 0.134. The mean cost per HZ patient from a payer/societal perspective was €153/€298, respectively, and the mean cost per HZ patients who developed PHN was €176/€426, respectively.

Conclusions

HZ is associated with impaired QoL and substantial health care resource use, highlighting the need for preventive strategies. This could reduce the disease burden for the patient and health care system.

ClinicalTrials.gov study registry

NCT01772160.

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.

Clinical and economic impact of herpes zoster vaccination in elderly in Italy

Herpes zoster (HZ) is a very relevant pathology among elderly people (≥ 60 years of age), with a considerable disease burden and loss of quality of life. In the last years a new vaccine against HZ became available in Italy. Therefore, the Italian decision makers are now confronted with the decision whether that vaccination should be implemented. Pharmaco-economic analyses represent useful tools to value the feasibility of new immunization programs and their sustainability. To this aim, an ad hoc population model was developed in order to value the clinical and economic impact of HZ vaccination program for the elderly in Italy. Particularly, different immunization scenarios were modeled: vaccination of 60 years-old subjects (single cohort strategy), simultaneous vaccination of people aged 60 and 65 years (double cohort strategy) and, lastly, immunization of people aged 60, 65 and 70 years (triple cohort strategy), thus leading to the vaccination of 5, 10 and 15 cohorts during the first 5 years of the program. The mathematical model valued the clinical impact of vaccination on the number of HZ, post-herpetic neuralgia (PHN) and ophthalmic HZ. The results of the analysis show that, in Italy, a cohort-based HZ vaccination program in elderly could have a relevant impact on the reduction of clinical cases and a favorable economic profile for the National Health Service (NHS), as already foreseen in other countries. In addition, further benefits could be obtained when extending the study period beyond the 5-year horizon of our analysis.