California, Louisiana and Maryland are now seeing widespread activity, while seven states are seeing regional activity: Alabama, Florida, Indiana, Nevada, New Hampshire, Tennessee and Texas.
In the United States, flu activity most commonly peaks between December and February.
The CDC noted that the contagious respiratory illness is extremely unpredictable, the timing, severity, and length of the season varies from one season to another.
The public health institute recommends that everyone 6 months of age or older receive an annual flu vaccine.
Influenza can cause mild to severe illness, and at times, can lead to death. On average, about 8% of the U.S. population gets sick from flu each season, according to the CDC.