OBJECTIVES: Routine influenza vaccination is fully reimbursed in most European countries for people aged over 65 years and those at high risk of complications. Lowering the age threshold for routine vaccination would reduce hospitalisations and deaths, as well as productivity losses during influenza outbreaks. We performed an economic evaluation of lowering the current age thresholds of 59 in Germany, and 64 in France, Italy and Spain to age 50 in these countries. METHODS: A decision analytic model was developed comparing a new policy providing universal reimbursement with current policy covering only those at high risk of complications in the 50-59/64 age group. We analysed costs and outcomes one over one influenza season from the perspectives of third-party payers (TPP) and society. The primary effectiveness measure was quality-adjusted life-years (QALYs). Model inputs were obtained from the published literature, complemented by expert opinion. Deterministic and probabilistic sensitivity analyses (PSA) were conducted. The value of acquiring additional information was explored. RESULTS: The estimated ICERs ranged from €13,156 to €28,568 per QALY gained from the TPP perspective. At a threshold of €50,000 per QALY gained, the probabilities of the new policy being cost-effective would be 93% for France, 72% for Germany, 89% for Italy, and 95% for Spain. From the societal perspective, the cost per QALY decreased to €9,318 in France and €4,195 in Spain, while cost savings are predicted for Germany and Italy. The greatest sources of uncertainty were ILI incidence rate, vaccine uptake, fatality rate and costs of vaccination. CONCLUSIONS: Routine influenza vaccination for people over 50 is likely to be cost-effective in France, Germany, Italy and Spain, and cost-saving from the societal perspective in Germany and Italy. The scope to reduce decision uncertainty is limited, as much of this stems from the unpredictable fluctuation in annual ILI incidence rate.