Herpes zoster burden of illness and health care resource utilisation in the Australian population aged 50 years and older
Introduction
Herpes zoster, also known as shingles, is a common illness caused by the reactivation of latent varicella herpes zoster virus (VZV), which causes varicella (chickenpox) during primary infection. It is a cause of considerable morbidity, especially in elderly patients, and can be fatal in immunosuppressed or critically ill patients. Herpes zoster is usually characterised by a unilateral, painful, vesicular cutaneous eruption with a dermatomal distribution. Although the blistering rash is the most distinctive feature of herpes zoster, pain associated with acute herpes zoster and its common complication, post-herpetic neuralgia (PHN), is the most common debilitating symptom, with a serious impact on quality of life. Opthalmic complications, especially uveitis are also common. The economic and social costs of managing the disease represent an important burden on both health services and society [1].
Epidemiological studies in temperate countries estimate the incidence of herpes zoster in the general population to be between 3 and 4 per 1000 persons [2], [3], [4], [5], [6]. However, the risk of developing herpes zoster increases markedly with age: the sharpest increase occurs between 50 and 60 years of age and continues on an upward trend thereafter, with herpes zoster incidence of more than 10 per 1000 persons reported for ages 60 and older [3], [7], [8], [9]. Similarly, the risk and severity of PHN increases with age, particularly in otherwise healthy adults aged 50 years and older [10], [11], [12].
The Shingles Prevention Study (SPS) [9] enrolled more than 38,000 adults 60 years and older and demonstrated that prophylactic administration of a live attenuated Oka/Merck varicella herpes zoster vaccine protected against herpes zoster (shingles) and PHN in 51 and 66.5% of cases, respectively. It reduced acute and chronic herpes zoster-associated pain, measured as the “burden of illness”, by 61%. An integrated analysis of two subsequent randomised clinical trials demonstrated zoster vaccination elicited similar immunogenicity in the 50–59 age group compared to those aged ≥60 years, suggesting the vaccine is likely to be effective in this age group [13], [14], [15]. Many developed countries are now considering scheduling of herpes zoster vaccine for older adults in their immunisation programs, especially as even with optimal antiviral therapy the risk of PHN remains substantial [7], [9]. In Australia and in Europe the herpes zoster vaccine is licenced for use in individuals aged 50 years and older and in the United States it is licenced and has been recommended from 60 years of age [13], [16], [17], [18].
Primary VZV infection typically occurs during childhood in temperate climates, with more than 90% of people infected by adolescence, whilst infection occurs later in tropical areas [19]. In Australia, seroepidemiologic data show that over 97% of the population aged 30 years and older is seropositive for VZV exposure, and is thus susceptible to herpes zoster [20]. Australia, a country of 20 million people, introduced universal infant varicella vaccination in 2005 [21]. However, the burden of herpes zoster is higher than that of varicella [22], [23]. An Australian study based on data from 1998/1999 showed that there were 4718 hospitalisations for herpes zoster compared to 1991 for varicella, with a mean length of stay in hospital of 4.2 days for varicella, and 7.2 or 16.5 days for hospitalisations with principal or secondary diagnosis of zoster respectively [22]. These data, however, are nearly a decade old.
The objective of this study was to evaluate the burden of illness and healthcare resource utilisation associated with herpes zoster in individuals aged 50 years and above in Australia, the population for whom the herpes zoster vaccine is licenced. Accurate determination of the health care burden and expenses associated with this disease is required to enable valid analyses of the cost-effectiveness of herpes zoster vaccination that can inform public health policy.
Section snippets
Incidence of herpes zoster and PHN
Age specific incidence of herpes zoster in Australia was estimated using general practice and pharmaceutical prescription data.
The Bettering the Evaluation of Care and Health (BEACH) program is a cross-sectional paper based national study of general practice clinical activity. Nationally representative samples of about 1000 active general practitioners (GPs)/family physicians, participate each year. Each GP records details of 100 consecutive GP-patient encounters of all types [24]. Patient
National age specific herpes zoster incidence based on extrapolated BEACH data
Patients aged 50 years and over accounted for 298,492 (46.2%) of all encounters recorded in the BEACH database between April 2000 and September 2006. Herpes zoster was managed at 632 of these encounters (0.21%), and 379 (60.0%) of these were marked as new. These numbers were extrapolated to an estimated annual average of 58,350 new herpes zoster cases amongst individuals 50 years and over, resulting in an estimated herpes zoster incidence of 9.7 per 1000 persons (Table 3). The estimated
Discussion
This study describes the considerable burden of herpes zoster in the 50+ population for which the herpes zoster vaccine is approved in Australia. Consistent with previous epidemiological studies in other temperate climate countries, such burden increases substantially with increasing age [2], [3], [5], [6], [9], [12], [28], [29], [40], [41].
Herpes zoster incidence rates in persons aged 50 years and above in Australia were estimated as 9.7 and 10.1 per 1000 persons, using primary healthcare and
Acknowledgements
The authors wish to thank Dr. Gordon Calcino from HI Connections Pty Ltd. for the analysis of age specific number of prescriptions for direct acting antiviral drugs available on the Pharmaceutical Benefits Scheme using data from Medicare Australia; Dr. Nicholas Mann, from the Hospitals Unit, Australian Institute of Health and Welfare for the extraction of herpes zoster hospitalisation data; Dr. Stuart McAllister, Director of Casemix Technical Development Department of Heath and Ageing for
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Modelling a cost-effective vaccination strategy for the prevention of varicella and herpes zoster infection: A systematic review
2021, VaccineCitation Excerpt :HZ is primarily an adult onset disease and has a significant health and quality of life impact in the majority of cases [8] with approximately 60% to 90% of patients experiencing postherpetic neuralgia (PHN) [9,10]. In an unvaccinated population the direct health costs in Australia of VZV and HZ have been estimated at $3.2 million/year [11] and $28.2 million/year [8] respectively, with a societal burden of VZV due to lost days of work and or school attendance of approximately $168 million per year (all in 2019 USD) [12]. Similarly, in the UK, hospital costs for VZV has been reported as over $8 million/year [13], and over $71 million/year to the Canadian health system [14], with societal costs in Germany of over $326 million per year (all in 2019 USD) [15].
Management of vaccination in rheumatic disease
2018, Best Practice and Research: Clinical RheumatologyCitation Excerpt :Varicella-zoster virus (VZV) infection is ubiquitous – as is the risk of VZV reactivation – leading to the usually painful herpes zoster (HZ, shingles) rash. The incidence of HZ in Australia, for example, is approximately 1/100, with the risk of viral reactivation increasing with age [42]. The mean age of HZ onset is 60 years, while half of those aged ≥85 years will develop HZ [43].