The number of people suffering from the flu in the U.S. is almost 10 times higher than last year in some cities.
In Boston, the city has declared a public health emergency and will begin offering free flu vaccinations.
Health authorities said flu season usually starts in December, but began in November this year.
The particular flu strain going around --H3N2 -- has a reputation for causing fairly severe illness, especially among the elderly.
Hospitals around the country are running out of space and some have had to turn people away.
The U.S. Center for Disease control recommends that everyone over the age of six months get a flu shot.
Flu cases on the rise across the U.S. (0:39)
Jan. 10 - Increase in flu cases in the U.S. prompts some cities to declare state of emergency. Julie Noce reports. ( Transcript )