The Recurring Burden of Flu

Flu returns every year and consistently places significant pressure on health systems. It is still often dismissed as mild or manageable, but remains a major cause of severe illness, hospital pressure and premature death, particularly among adults over 60.^1-11

The seven countries included in the Flunomics report (United States, England, Germany, Spain, Italy, France and Japan) all had a national flu vaccination program in place for the 2024/2025 season. Yet the data indicates that flu hospitalizations in older adults are costly and recurrent – in the US, average inpatient costs exceed $34,000 per stay, with high rates of readmission making flu a persistent strain on the healthcare system.^12,13

Why Did This Happen? What Can We Do Better?

Although policies existed, their implementation fell short. Delays in rollout, rigid procurement, and limited coverage left many high-risk people—especially older adults—without timely or adequate vaccination. This protection gap led to higher hospitalizations, excess deaths, and growing economic costs.^14-16

Flunomics brings this gap into sharper focus and enables healthcare leaders and policymakers to see where systems struggled, where surveillance systems are preventing a timely view of seasonal impact, why data-driven, targeted flu preparedness is essential, and what can be done to reduce morbidity and mortality.

The report analyzes seven countries across four key dimensions:

• Hospital burden: Admissions, ICU use, and mortality
• Economic cost: Flu’s financial impact on health systems
• Policy vs. reality: Where policy implementation fell short and how it could be improved
• Protection gaps: Who remains under-protected and why

And this is just the start. We hope this information will drive key stakeholders to make changes to improve protection in future flu seasons. Sanofi will continue to monitor and share insights on flu impact, using evolving data to support ongoing conversations around preparedness, policy, and public health.