What is happening with this year’s flu season? According to this chart from the Centers for Disease Control, the season is beginning slowly, like most previous years, and it will take a few weeks to determine if the season will be mild or severe. Under any circumstances, it would be wise to be immunized soon: the season usually worsens in December-January, and the vaccine takes two to three weeks to become fully effective. (The CDC’s latest Weekly U.S. Influenza Surveillance Report can be found here.)