CDC labels 2025–26 flu season ‘moderately severe’ as estimated illnesses reach 11 million

The U.S. Centers for Disease Control and Prevention has classified the 2025–26 influenza season as “moderately severe,” according to a Reuters report published January 5, 2026, based on CDC data. The assessment came as flu activity remained elevated and rose during the final week of December, a period that often reflects the impact of holiday gatherings and heavy travel.

The CDC’s estimates put the season’s toll so far at at least 11 million illnesses, about 120,000 hospitalizations, and roughly 5,000 deaths. While these figures can shift as surveillance data is updated and more hospital reporting arrives, the early classification signals that the burden is meaningfully higher than what the agency was seeing at a similar point in the prior season.

Public health experts told Reuters that several forces may be contributing to the rise: holiday travel that increases contact rates, relatively low vaccination uptake in some communities, and the spread of misinformation that can discourage preventive steps. Those pressures can also strain clinics and hospitals, especially when flu overlaps with other winter respiratory illnesses.

According to the report, influenza A(H3N2) has been the dominant strain, accounting for the vast majority of subtyped influenza A cases. H3N2 seasons have historically been associated with heavier impacts in older adults, though severity varies by year and by how well vaccine composition matches circulating viruses.

CDC officials indicated that flu activity is likely to continue for several weeks. Health systems and local public health departments typically respond by amplifying vaccination outreach, reminding the public about antiviral treatment windows, and reinforcing guidance around staying home when sick, improving ventilation, and protecting high-risk individuals.