The Centers for Disease Control and Prevention (CDC) has confirmed the first child death from influenza in the 2025-2026 respiratory virus season, at a time when the United States is experiencing a sharp rise in infections from a new H3N2 – subvariant K strain.

Health officials in Colorado reported the death of a child in elementary school in Denver last week, although it is not yet confirmed if this case is directly linked to the new strain. The H3N2 subvariant has been described as “new to immune systems,” increasing the likelihood of severe complications requiring hospitalization.

Data from the CDC indicates that 89% of influenza A samples analyzed since September belong to this strain. More than 30 states are witnessing rising cases, with Colorado reporting a 43% increase in hospital admissions due to influenza in late November.

Nationally, positive influenza test rates rose to 8.1% in the first week of December, compared to 7.1% the week before, alongside increased outpatient visits for respiratory illnesses.

CDC estimates that approximately 3 million people have been infected this season, with 1,200 deaths and around 30,000 hospitalizations recorded so far, prompting renewed calls for seasonal flu vaccination and preventive measures.