The number of states in the U.S. Reporting widespread flu cases has more than doubled since last week.
According to the Flu Update, issued by the Centers for Disease Control and Prevention, 25 states are reporting widespread activity.
The CDC says "widespread" means more than half of geographic regions in a state - counties, for example - are reporting flu activity.
The most severe activity seems to be located in the southeastern states.
But health experts say the 2013-2014 flu season still remains typical and should peak in January or February.
The most common strain of flu this year has been H1N1, which became known as Swine Flu during a 2009 outbreak.The strain is so common that it was included in this year's vaccination, according to the CDC.
Doctors say the best way to fight the flu is to get vaccinated. Also, keep hands clean and wash your hands as much as possible.