CDC labels the 2025–26 flu season ‘moderately severe’ as U.S. cases pass 11 million, Reuters reports

U.S. seasonal influenza activity has remained elevated and increased in late December, prompting the Centers for Disease Control and Prevention to classify the 2025–26 flu season as “moderately severe,” according to a Reuters report. The designation matters because it signals not only the level of transmission but also the strain on hospitals, emergency departments and outpatient clinics at a time when winter respiratory illnesses often overlap.

CDC estimates put the season’s toll so far at at least 11 million illnesses, about 120,000 hospitalizations and roughly 5,000 deaths. The agency has said influenza activity is likely to continue for several weeks, meaning communities could still see additional waves, especially as schools and workplaces cycle through post-holiday routines and people spend more time indoors.

Public health experts interviewed by Reuters pointed to several drivers that can amplify spread, including heavy travel during the holiday period, relatively low vaccination rates in some areas, and widespread misinformation that can reduce uptake of basic prevention measures. When vaccination rates are uneven, local outbreaks can build quickly and put disproportionate pressure on specific hospitals and urgent-care networks.

The dominant strain this season has been influenza A(H3N2), which is often associated with more severe seasons, particularly for older adults and people with underlying health conditions. As the season progresses, clinicians and public-health officials will keep watching indicators such as emergency department visits for flu-like illness, lab-confirmed positivity rates and the geographic spread of outbreaks.

Health agencies typically emphasize several layered steps to reduce risk: vaccination, staying home when sick, improving indoor ventilation where feasible, and seeking medical care promptly for severe symptoms—especially for those in higher-risk groups. Antiviral medications can also reduce severity when started early, but access and timing depend on awareness and clinical pathways.

While the “moderately severe” label is not a forecast of what will happen next, it is a warning that the season is already substantial and may continue to stress parts of the health system. The next several weeks will help determine whether the country sees a prolonged plateau of high activity or a more rapid decline as winter progresses.