Cost-effectiveness of 13-valent pneumococcal conjugate vaccine (PCV13) in older Australians
Introduction
Pneumococcal diseases are due to infection with the bacterium Streptococcus pneumoniae and have a spectrum of clinical severity, with invasive pneumococcal disease (IPD) and pneumonia without IPD being most severe [1]. Community-acquired pneumonia (CAP) is a frequent non-invasive disease type [2] responsible for a large burden of hospitalisation and death in older adults [3]. Pneumococcal disease remains a leading cause of death globally [4] and is highest at the extremes of age, including children <5 years old and the elderly [1], [5].
In 2005, pneumococcal polysaccharide vaccine (PPV23) was fully funded by the Australian government for all Australians aged ≥ 65 years and placed on the Australian National Immunisation Program (NIP) [6]. Prior to 2005 there had been moderate uptake (49.5%) in older Australians [7] as a result of private purchase, public funding in one state (Victoria), as well as targeted PPV23 programs (e.g. in Aboriginal and Torres Strait Islanders >50 years old [5]). After universal funding, a national survey in 2009 estimated self-reported uptake of ∼60% among Australians aged ≥65 years [8]. However, the impact and value for money of PPV23 programs has been questioned in Australia and in other settings [9], [10], [11].
The 7-valent pneumococcal conjugate vaccine (PCV7) was also publicly funded from January 2005 for all Australian infants (on a 3+0 schedule at 2, 4, 6 months [6], with a catch-up program for children <5 years). PCV7 was replaced by PCV13 in July 2011 to combat increases in IPD caused by serotypes not included in PCV7 [6]. Both infant PCV programs have resulted in major reductions in IPD incidence in infants and among adults through herd protection [5].
In 2015, the Community Acquired Pneumonia Immunisation Trial in Adults (CAPiTA) provided new evidence for the efficacy of PCV13 in the prevention of vaccine-type IPD and CAP in older adults [12]. Cost-effectiveness studies published prior to CAPiTA typically overestimated the efficacy of PCV13 against vaccine-type CAP [13] and only a small number of studies have been published since the new CAPiTA data became available [14], [15], [16], [17].
In Australia, PCV13 was recently recommended for funding by the Pharmaceutical Benefits Advisory Committee (PBAC) as a replacement for PPV23 in older adults [18]. In this study we explore the cost-effectiveness of PCV13 (or PPV23) vaccination at the age of 65 years, as well as the impact of varying key uncertain parameters and the age of vaccination.
Section snippets
Model
A single-cohort deterministic Markov model was developed to describe the impact of pneumococcal disease and vaccination. Costs (Australian dollars, A$) and health effects (measured in Quality Adjusted Life-Years, QALYs) were attached to model states, with each discounted at 5% annually [19]. In the base-case model, a cohort of 65 year olds (∼240,000) was followed up to age 100 years in yearly cycles. The initial population size was based on the 2017 (projected) population initially with
Results
For the cohort we project that 60% coverage with PCV13 at age 65 years would prevent 39 hospitalisations and 6 deaths due IPD as well as 180 hospitalisations, 10 deaths and 453 GP visits due CAP. The PPV23 program in the same cohort was estimated to prevent 27 hospitalisations and 4 deaths from IPD. Further details of the projected impact of PCV13 and PPV23 are presented in Appendix 1 Table 1.
In base-case analysis, the total cost of vaccinating those aged 65 years with PCV13 was ∼A$11,120,000.
Discussion
Our analysis compared PCV13 to PPV23 vaccination as well as no-vaccination. The direct comparison to PPV23 aims to identify the relative value for money of switching to PCV13, with comparison to no-vaccination, providing an estimate of the overall value for money of each program, for comparison with other spending choices. In our base-case model, the implementation of a PCV13 program in Australians aged 65 years was estimated not to be cost-effective (threshold of $60,000 per QALY gained) when
Conclusion
In comparison to no-vaccination, we found that PCV13 use in those aged 65 years was unlikely to be cost-effective unless the vaccine price was below A$46 or a longer duration of protection can be established. However, we found that in comparison to the PPV23, vaccination of 65 year olds with PCV13 was cost-effective. This partly reflects the poor value for money estimated for PPV23 in Australia. The results suggests that replacement of PPV23 with PCV13 may be warranted given the relative better
Potential conflict of interest
Raina MacIntyre has been on advisory boards for both Pfizer and Merck on pneumococcal vaccines and received in kind support in the form of testing of specimens for pneumococcal serology from Pfizer for an investigator-driven trial comparing conjugate and polysaccharide vaccines.
A university chair in Philippe Beutels’ centre at the University of Antwerp was supported in 2009–2016 by a gift from Pfizer, and this chair is now also supported by GSK. There is no connection between either Pfizer, GSK
Acknowledgements
This research was supported by an Australian National Health and Medical Research Council Project grant (1081344). NNDSS data on IPD notification and deaths were provided by the Office of Health Protection, Department of Health on behalf of the Communicable Disease Network Australia and the Enhanced Invasive Pneumococcal Disease Surveillance Working Group.
Mortality data on CAP were sourced from the Australian Bureau of Statistics, Causes of Death. Department of Health provided the data on the
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2018, VaccineCitation Excerpt :There are limited available Australian data on the aetiology of CAP, we assumed 13.9% of all CAP was due to pneumococcal infection [18] and (due to a lack of data) we assumed that the proportion of this due to PPV23-types was the same as that observed for IPD in the same year and age group. The rates of CAP general practitioner (GP) visits, hospitalisation, as well as the hospitalisation-fatality rates following CAP were the same as those used in a previous cost-effective analysis of PCV13 vaccination in older Australians [19]. There is no routine collection of PPV23 coverage data at a national level.
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The role of timeliness in the cost-effectiveness of older adult vaccination: a case study of pneumococcal conjugate vaccine in Australia
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