WASHINGTON — Flu activity has seen a sharp uptick across the country, according to data from the Centers for Disease Control and Prevention, with hospitalizations increasing and the number of illnesses so far this season far outpacing the number at the same time last year.
The CDC’s weekly U.S. flu surveillance report, released Tuesday, showed key flu indicators, from hospitalization rates to deaths to positive flu lab tests, all up from the previous week.
Hospitalizations, in particular, have seen a sharp increase, with the number of patients admitted for the flu nearly doubling in a week, from just under 10,000 to just under 20,000.
The CDC reported five new influenza-associated pediatric deaths during the week, bringing the total number of children who have died from flu-related illness for the current season to eight.
Overall, the federal health agency estimates there have been at least 7.5 million illnesses, 81,000 hospitalizations and 3,100 deaths from the flu so far in the 2025-2026 season.
That marks a dramatic increase from last year, when the CDC estimated there were at least 3.1 million illnesses, 37,000 hospitalizations and 1,500 total deaths at the same point in the 2024-25 season.
So far this season, all three categories are more than double what they were at the same time last year. The CDC noted in its report that “influenza activity is expected to continue for several weeks.”
Last season, flu hospitalizations didn’t peak until February, marking the highest spike in more than a decade.
Much of the activity so far, according to CDC data, is due to a new strain — a variant of influenza A, and specifically A(H3N2) — known as subclade K, with some referring to it and the surge it caused colloquially as the “super flu.”
According to the CDC, of the 275 influenza A(H3N2) viruses collected since September 28, 2025 and further genetically characterized, 89.5% belonged to the K subclade.
Meanwhile, the CDC reported that the number of states experiencing “high or very high” flu activity increased from 17 to 32 in the previous week.
States with the highest activity include New York, Colorado, South Carolina and Louisiana, followed by New Mexico, Idaho, Michigan, New Hampshire, Massachusetts and Connecticut.
New York State, for example, between December 14 and 20 experienced the highest number of flu cases ever recorded in a single week, said its health commissioner, Dr. James McDonald. The total of 71,123 cases for the week represents a 38% increase from the previous seven-day period.
The CDC report released Tuesday covered the week ending December 20. The following week’s update is expected to be released on Monday.
The government health agency faced uncertainty after Health and Human Services Secretary Robert F. Kennedy Jr. ousted members of his top immunization advisory committee and replaced them with his own picks, leading to changes in vaccine recommendations, with more potentially to come.
The CDC notes in its weekly update that it recommends that everyone 6 months and older receive an annual flu vaccine.
