Public Health Impact and Cost-Effectiveness of Non-live Adjuvanted Recombinant Zoster Vaccine in Canadian Adults

Applied Health Economics and Health Policy https://doi.org/10.1007/s40258-019-00491-6 ORIGINAL RESEARCH ARTICLE Public Health Impact and Cost‑Effectiveness of Non‑live Adjuvanted Recombinant Zoster Vaccine in Canadian Adults Ashleigh McGirr1 · Desiree Van Oorschot2 · Robyn Widenmaier1 · Michael Stokes3 · Michael L. Ganz4 · Hyosung Jung4 · Lijoy Varghese5 · Desmond Curran2 © The Author(s) 2019 Abstract Objectives In Canada, incidences of herpes zoster (HZ) and postherpetic neuralgia (PHN) are increasing, posing a significant burden on the healthcare system. This study aimed to determine the public health impact and cost effectiveness of an adjuvanted recombinant zoster vaccine (RZV) compared to no vaccination and to the live attenuated vaccine (ZVL) in Canadians aged 60 years and older. Methods A multi-cohort Markov model has been adapted to the Canadian context using recent demographic and epidemiologic data. Simulations consisted of age-cohorts annually transitioning between health states. Health outcomes and costs were discounted at 1.5% per year. The perspective of the Canadian healthcare payer was adopted. A coverage of 80% for the first RZV and ZVL dose and a compliance of 75% for the second RZV dose were assumed. Results RZV was estimated to be cost effective compared with no vaccination with an incremental cost-effectiveness ratio (ICER) of $28,360 (Canadian dollars) per quality-adjusted life-year (QALY) in persons aged ≥ 60 years, avoiding 554,504 HZ and 166,196 PHN cases. Compared with ZVL, RZV accrued more QALYs through the remaining lifetime and an increase in costs of approximately $50 million resulting in an average ICER of $2396. Results were robust under deterministic and probabilistic sensitivity analyses. HZ incidence rate and persistence of vaccine efficacy had the largest impact on cost effectiveness. Conclusions The cost-utility analysis suggested that RZV would be cost effective in the Canadian population compared with no vaccination and vaccination with ZVL at a willingness-to-pay threshold of $50,000. Plain Language Summary More than 95% of adults aged 50 are infected with varicella-zoster virus and are at risk of developing herpes zoster, also known as shingles. This risk is higher in older people and in people with a reduced immune system. Shingles causes a painful rash and may trigger persistent pain and other complications that greatly reduce quality of life. In Canada, Zostavax is the only existing approved vaccine against shingles. It has been offered in a publicly funded program in Ontario to those aged 65–70 years since September 2016. Shingrix, is a new shingles vaccine that has recently been approved by Health Canada for adults aged ≥ 50 years. The present model suggests that Shingrix confers higher protection against shingles compared to Zostavax, with a greater reduction in shingles episodes. The increase in vaccination costs would be partially offset by reduced healthcare visit and medication expenses. For these reasons, provincial health plans may consider offering Shingrix to people aged ≥ 50 years. Electronic supplementary material The online version of this article (https://doi.org/10.1007/s40258-019-00491-6) contains supplementary material, which is available to authorized users. * Ashleigh McGirr 1 GSK, Mississauga, Canada 2 GSK, Wavre, Belgium 3 Evidera, Saint‑Laurent, Canada 4 Evidera, Waltham, MA, USA 5 GSK, Singapore, Singapore Vol.:(0123456789) A. McGirr et al. 1 Introduction Herpes zoster (HZ) arises in older individuals due to the reactivation of latent varicella zoster virus. Approximately 95% of all adults aged ≥ 50 years are infected with varicella zoster virus in their youth and thus at risk of developing HZ [1]. The life-time risk of developing HZ for subjects with prior varicella ranges between 15 and 30% with a sharp increase in HZ incidence after the age of 50 [2–4]. HZ starts usually with prodromal pain, followed by a painful unilateral rash which lasts approximately 1 month [5, 6]. In 8–33% of individuals with herpes zoster, pain persists after the acute phase and develops into postherpetic neuralgia (PHN) [6, 7]. Other complications, including disseminated zoster and neurological complications, may occur and are more frequent and severe in older or immunodeficient individuals [8]. HZ and its complications severely impact the quality of life of patients by interfering with sleep and activities of daily living due to pain [9]. Direct medical costs due to HZ-, PHN- and HZ-related complications impose a substantial burden to the healthcare system, annually estimated at 68 million Canadian Dollars (referred to as $ hereafter) in Canada [10]. Recent studies have found a steadily increasing trend in the incidence of HZ over time, beyond that expected by demographic shifts alone [4, 11, 12]. Furthermore, current treatment options, based on antivirals, analgesics, opioids, and tricyclic antidepressants, fail to achieve complete symptom relief leading to low patient satisfaction regarding treatment efficacy [13, 14]. The burden of HZ on the Canadian healthcare system and patients is expected to increase in the future [8, 15]. Zoster Vaccine Live (ZVL, Zostavax), a live attenuated virus vaccine indicated for prevention of HZ, was the only approved vaccine for HZ in Canada until recently. At the time of analysis, ZVL was offered under a universal vaccination program in Ontario and restricted to people aged 65–70 years [16]. There are several limitations associated with ZVL: (i) vaccine efficacy (VE) against HZ is lower in older individuals who are at higher risk of developing HZ [12, 17], (ii) VE decreases over time with long-term follow-up data suggesting no remaining protection 8 years after vaccination [18], (iii) ZVL is contraindicated in some patients with primary and acquired immunodeficiency [17]. A non-live adjuvanted recombinant zoster vaccine (RZV, Shingrix) has recently been approved in Canada as a twodose vaccine in persons aged ≥ 50 years [19]. RZV combines glycoprotein E with an adjuvant system, A S01B, intended to enhance the immunological response to the antigen [20]. The clinical profile of RZV is different from ZVL, with placebo-controlled clinical trials suggesting higher initial VE against HZ and PHN and modest waning during the initial 4-year period, although longer follow-up studies are ongoing [21, 22]. In June 2018, the National Advisory Committee on Immunization recommended that RZV should be offered to populations aged ≥ 50 years without contraindications [23]. The Comité sur l’immunisation du Québec has recommended the preferential use of RZV over ZVL [24]. The goal of this study was to evaluate the public health impact and cost effectiveness of RZV compared to (i) no vaccination and (ii) ZVL vaccination in Canadian adults aged ≥ 60 years from the perspective of the healthcare payer. Secondary analyses were conducted in persons aged ≥ 50 years. 2 Methods 2.1 Model Overvi (...truncated)