Pharmacoeconomics of influenza vaccination in the elderly: reviewing the available evidence.

Most western countries have influenza vaccination programmes for citizens aged > or = 65 years. This paper reviews the available evidence on whether elderly influenza vaccination is worthwhile from a pharmacoeconomic point of view. A search on Medline and EMBASE resulted in a primary selection of approximately 100 studies on the pharmacoeconomics of influenza vaccination in the elderly. Further selection of studies to be included in the review was based on several criteria such as original research paper, cost-benefit or cost-effectiveness analysis. influenza vaccination in the elderly, and publication between 1980 and 1999. The 10 studies included in the final selection were evaluated regarding 3 main aspects: benefit-cost ratio and cost-effectiveness ratio; vaccine effectiveness; and relative costing of the vaccine. In general, differences in benefit-cost ratios could be explained by differences in effectiveness and relative costing of the vaccine. Considering the available pharmacoeconomic evidence, influenza vaccination of the elderly in western countries is an intervention with favourable cost-effectiveness in terms of net costs per life-year gained and even has cost-saving potential. In particular, influenza vaccination among elderly people at higher risk, such as the chronically ill elderly, is generally found to be cost saving. Relatively favourable cost-effectiveness among non-high-risk elderly justifies universal influenza vaccination of the elderly from a pharmacoeconomic point of view.