The Centers for Disease Control is warning the flu season appears to be bad this year -- spreading faster and earlier than usual.
The CDC says the south and southeast section of the country is getting hit hard.
Even people who received the flu shot can still get sick.
There is one theory that the outbreak may be due, in part, to the possibility that the flu vaccine does not include the strain that is currently spreading across the country.
But the CDC disagrees, saying the influenza virus people are being infected with appears to be covered by this year's vaccine.