Early flu activity is leading to hospitalization rates that haven't been seen in a decade.
According to the Centers for Disease Control, hospital rates are highest among adults 65 years and older and children 4 years and under.
There is concern that hospitalization will only rise because flu season typically peaks between December and February.
"Lower coverage and little flu circulation for two years may have reduced population immunity, especially in young kids, which could lead to more flu illnesses this season, and potentially more severe illness," the CDC said in a statement.
The CDC notes that the flu vaccine is widely available, but vaccination rates remain down. The health agency notes that as of Oct. 8, nearly 23 million flu vaccines have been given at pharmacies and physician offices. That's down from 27 million doses given at the same time in 2021.
Flu isn't the only respiratory virus circulating at elevated levels right now, the CDC says. It notes that hospitals are also treating patients with RSV and COVID-19.