Objective: Influenza cost-effectiveness studies use models for influenza clinical evolution based on a range of assumptions. We explore the importance of these assumptions and its implications in policy decisions.
Methods: An influenza model was constructed to measure the cost-effectiveness of universal influenza vaccination of people over 50 years compared to current policy to vaccinate people over 65 years in Australia using available epidemiological data. We explored two scenarios, one with an Australian estimate of influenza like illness incidence, and one with a European estimate. Further, we estimated uncertainty of model structure and various parameter assumptions, and compared with a previous study.
Results: The scenario and sensitivity analysis has shown the incremental cost-effectiveness ratio of the proposed compared to current policy varies from $112,000 to $6,000 per DALY. The model structure, parameter assumptions and limitations of existing epidemiological data lead to extensive unaccounted uncertainties in previous studies.
Conclusion: The lack of influenza epidemiological data makes the influenza cost-effectiveness studies that compare the universal influenza vaccinations of people over 50 years to current policy unreliable.
Implications: It is imperative to appraise unreliability of influenza cost-effectiveness studies in policy decisions. Research to acquire more data on influenza uncertainties in Australia should be funded.