A study in CMAJ in September 2024 evaluates the cost-effectiveness of different age cut-offs for RSV adult vaccination programmes, with or without a focus on people with higher disease risk. The authors compared alternative age-, medical risk-, and age- and medical risk-based policies. They found that, although all vaccination strategies “averted medically attended RSV disease”, universal age-based strategies were a less efficient use of resources than medical risk-based strategies.
The study
By May 2024, two RSV vaccines were approved for use in Canada in adults aged 60 years and older: RSVPreF3 and RSVpreF. The researchers performed a model-based cost-utility analysis of RSV vaccination programmes in the Canadian population aged 50 years and older. They developed a static individual-based model of medically attended RSV disease to consider the effects of various policies on RSV-associated outcomes. The model followed a multi-age closed population of 100,000 people over a 3-year period. Individuals were characterised by the presence or absence of 1 or more chronic medical conditions.
The authors evaluated a combination of age-only, medical risk-only, and age- plus medical risk-based single-dose vaccination strategies:
- Age-based: all people the same age or older than the specified age cut-off were eligible to receive the vaccine.
- Medical risk-based: only people aged greater than or equal to the specified age cut-off who also had 1 or more chronic medical conditions were eligible to receive the vaccine.
- Age- plus medical risk-based strategies: people were eligible to receive the vaccine if they met an age requirement, or if they were younger and had at least 1 chronic medical condition. A lower age bound was evaluated for these strategies.
Study results
Results were “not appreciably different” for the 2 vaccines evaluated. For both vaccines, a programme that focused on vaccinating people with at least 1 chronic medical condition aged 70 years and older was the “optimal” strategy for a cost-effectiveness threshold of $50,000 per quality-adjusted life year (QALY). Lowering the age recommendations to people with at least 1 chronic medical condition aged 60 years and older resulted in sequential incremental cost-effectiveness ratios (ICERs) of around $100,000 per QALY gained compared with a medical risk-based policy for those aged 70 years and older.
“Age-only strategies were never identified as cost-effective options regardless of the cost-effectiveness threshold used, when compared with other strategies.”
Vaccinating adults aged 80 years and older resulted in sequential ICERs of $3261-$5391 per QALY gained. Lowered age recommendations to 75 years and older required a cost-effectiveness threshold of approximately $80,000 per QALY.
Conclusions
The analysis highlights that the strategies that focussed on adults with underlying medical conditions putting them at increased risk of RSV disease are more likely to be cost-effective than general age-based strategies. Vaccination of older adults may be “less costly and more effective” than no vaccination, and vaccinating people aged 70 years and older with chronic medical conditions is “likely to be cost-effective”. Broader programmes may also be more cost-effective in settings with higher risk of disease and health care costs.
The authors conclude that RSV vaccination programmes have the potential to avert a substantial burden in older adults if appropriately targeted.
“RSV vaccination programmes in some groups of older Canadians are expected to be cost-effective, with programmes focusing on people with underlying medical conditions that place them at increased risk of severe RSV disease expected to provide the best value for money.”
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