Flu cases continue to rise across the U.S.

(NBC) - Hospitals in the nation are seeing a rise in the number of patients coming in with the flu in almost every state except for Hawaii.

The predominant strain is H3N2, which often causes more severe illnesses, especially those older than 65 and the very young.

So far this season as least 20 children have died with the flu.

While most people recover just fine from the flu, get to a hospital if you're having trouble breathing, can't keep fluids down, or have a fever over 100 that lasts for more than a day.