And this is important because as we head into the holidays, a lot of people will be traveling, spending time in airports or on buses, or even at parties.
Action News Registered Nurse Ali Gorman says this is when we see illnesses start to spread.
Flu activity is high in Texas, Louisiana, and Mississippi.
Now is the time to make sure you are washing your hands often.
And if you haven't already, to get a flu shot. Many of the strains going around this year, including the H1-N1 swine flu, are covered in this year's vaccine.