A guide to critical reading of influenza vaccine cost-effectiveness analyses.

Introduction: Influenza vaccines are formulated each year to prevent serious illness in at-risk individuals, including elderly people. Healthcare decision-making is mainly based on the economic evaluations (EEs) (i.e., cost-effectiveness analysis [CEA]) of vaccines; however, understanding the limitations of these models and correctly interpreting the results may be challenging. Here, we provide a practical Guide that will help readers who are not experts in the field of health economics or influenza to critically review influenza vaccine EEs. Methods: This Guide is based on the findings of a systematic review of the literature, a critical analysis of the available EEs published for influenza vaccines for older adults in Spain, and applicable national and international guidelines on EE and influenza modeling. It has been developed by a multidisciplinary board of experts in influenza, vaccines, and health economics. Results: The guide provides tips to help the reader assess whether an EE design is fit for its purpose in terms of comparators, time horizon, perspective of the analysis, population analyzed, and whether appropriate modeling methods were applied. It detects the uncertainty arising from input data and the implications of this uncertainty on the results. Conclusions: Ultimately, this resource aims to empower decision-makers, particularly those without expertise in health economics or vaccinology, to critically read and interpret EEs, thus favoring evidence-based informed decisions that will improve the efficiency of influenza vaccination programs.