Cost-Benefit Analysis of Vaccination Against Four Preventable Diseases in Older Adults: Impact of an Aging Population

OBJECTIVE
This exploratory study estimates the economic value of the current vaccination program and increased coverage against four preventable diseases in older adults in the United States (US).


METHODS
A population-based, age-structured economic model was used to conduct a cost-benefit analysis of vaccination against influenza, pertussis, herpes zoster, and pneumococcal disease among US adults aged 50 years and older, accounting for aging of the population. The model used separate decision trees for each disease to project the discounted number of vaccinated individuals, number of disease cases, and direct medical and indirect costs (2018 US$) over a 30-year period. Benefit-cost ratios (BCRs) and net present values were calculated for two primary analyses comparing current vaccination coverage versus no vaccination and comparing increased coverage versus current coverage. Key parameter values were varied in deterministic sensitivity analyses.


RESULTS
Current adult vaccination coverage (vs. no vaccination) is estimated to result in nearly 65 million averted disease cases, $185 billion averted costs of cases, and $136 billion in incremental vaccination costs over a 30-year period from a societal perspective (BCR = 1.4). Increased vaccination coverage (vs. current coverage) is associated with over 33 million additional averted disease cases, $96 billion additional averted costs of cases, and nearly $83 billion in incremental vaccination costs, resulting in a societal BCR of 1.2 over 30 years. Deterministic sensitivity analyses demonstrated that results were most sensitive to disease incidence, vaccine efficacy, and productivity costs for time required for vaccination.


CONCLUSIONS
Study results highlight the economic value of vaccination programs for older adults in the US and indicate that efforts to further increase vaccination coverage may be warranted and economically justifiable.

• The research discussed in this presentation was funded by GlaxoSmithKline Biologicals S.A. • Justin Carrico and Sandra Talbird are employed by RTI Health Solutions, which received funding for the conduct of these studies.

Background
RTI-HS has collaborated with vaccine manufacturers to establish a consortium to pursue above-brand health economics and outcomes research initiatives.
The Summit is providing feedback to this new consortium on research priorities to improve adult vaccination.
A top research priority communicated by the Access and Provider WG is to estimate burden of illness of adult vaccine preventable diseases and the economic value of adult immunization.

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• What is the economic burden of influenza, pertussis, herpes zoster, and pneumococcal disease in adults aged 50 years and older in the US? • What is the return on investment for current and increased vaccination coverage against these four preventable diseases?• For both research questions above, what is the impact of the US population shift towards older age groups over the next 30 years?
Research Questions Due to population growth and the shifting age distribution over the next 30 years, annual societal burden of the four diseases is projected to increase from $35 billion to $49 billion.
$1.3 trillion in cumulative societal costs over 30 years and over 1 million deaths were projected if vaccination coverage remained at current levels. 9

Results: Cost-Benefit Analysis of Vaccination Against Four Preventable Diseases in Older Adults
When compared with no vaccination, current adult vaccination coverage is estimated to result in 65 million averted disease cases, $185 billion averted costs of cases and $136 billion in incremental vaccination costs.
Benefit-cost ratio = 1.4 Increased vaccination coverage was associated with 33 million additional averted cases and additional cost savings relative to current vaccination coverage.
Benefit-cost ratio = 1.2 A benefit-cost ratio (BCR) is the ratio of benefits of an intervention, expressed in monetary terms (e.g., cost of disease cases avoided), relative to the cost of the intervention (e.g., cost of vaccination).
Current coverage vs. no vaccination Increased coverage vs. current coverage 9 10 • The four vaccine-preventable diseases were modeled over time separately.• Population-level mortality and vaccine coverage projections used did not account for extraordinary events (e.g., COVID-19 pandemic).• Costs of disease cases only included acute care and did not account for the management of long-term sequelae.• Indirect effects of vaccination, such as herd immunity and serotype replacement, were not modeled.

Limitations
• Maintaining current vaccine coverage rates among older adults is projected to lead to increased burden of influenza, pertussis, herpes zoster, and pneumococcal disease.• Efforts to further increase vaccination coverage in older adults may be warranted and economically justifiable.

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A population-based, age-structured economic model was constructed to project disease and vaccination program costs over a 30-year period (2017-2046).• Projected population estimates from the US Census Bureau were used to account for changes in the US population over time.• Disease incidence among unvaccinated, along with vaccination coverage, efficacy, and waning was used to calculate annual disease cases.Methods: Economic Model 7 Burden of Disease Analysis Cost-Benefit Analysis • Current estimates (as of 2017) of disease incidence, vaccine coverage, and efficacy remained constant over time.• Clinical outcomes and costs of disease were projected over 30 years.• Compared outcomes over 30 years for three vaccination coverage scenarios: -No vaccination -Current vaccination coverage -Increased vaccination coverage • Calculated the return on investment (expressed as a benefit-cost ratio) for current vaccination coverage and increased vaccination coverage. of Population Aging on the Burden of Four Vaccine-Preventable Diseases

Conclusions 11 12 •
Impact of population aging on the burden of vaccinepreventable diseases among older adults in the United States• Cost-benefit analysis of vaccination against four preventable diseases in older adults: Impact of an aging populationLinks to Research