OBJECTIVES: In considering the inclusion of healthy adults aged 50-64 in the yearly influenza vaccination scheme, the Dutch ministry of health had issued a study on the balance of costs and effects of vaccination compared to no vaccination, as well as the budget impact. METHODS: An available decision model was adapted to assess the cost-effectiveness of influenza vaccination for healthy adults assuming average influenza epidemic severity. Excess cardiovascular complications leading to hospital admissions were accounted for. Both the peri-season and the summer were used as reference period to estimate the (excess) disease incidence and the influenza related complications. Direct medical costs as well as losses in productivity were accounted for. RESULTS: When using the peri-seasonal period as the reference period, the discounted incremental cost-effectiveness ratio (iCER) was € 28.019 per life year saved. For the subgroup analyses 50-54, 55-59 and 60-64 the iCERs were estimated at €44.558; €37.632 and €15.810 per life year saved. The net budget impact following an expansion of the vaccination program with healthy adults 50-was estimated at 18 million euros annually. In case the summer would be used as the reference period, the discounted iCER was €9.421 per life year saved. For the subgroup analyses 50-54, 55-59 and 60-64 the iCER were estimated at €19.036; €11.151 and €4.314 per life year saved. The net budget impact following would amount to 12.9 million euros annually. CONCLUSION: The iCER depended on the reference period chosen in the analyses. Subsequent policy decisions making could as a result lead to different outcomes. Based on the most conservative estimates, the iCER fell below €20.000 per life year gained only for healthy adults aged 60-65. With the summer as reference period, the entire age cohort 50-64 fell below €20,000 per life year gained.