Words like "epidemic" tend to get tossed around willy nilly whenever flu seasons get nasty. But Centers for Disease Control and Prevention officials confirmed Friday that what the U.S. is going through right now officially qualifies as an epidemic. They estimate that 7.3 percent of deaths last week were cause by influenza and pneumonia. That means the flu just squeaked past the threshold for an epidemic: 7.2 percent.  

In a teleconference Friday afternoon, CDC director Thomas R. Frieden said 47 states had widespread influenza activity. Researchers have determined that this year's flu shots are 62 percent effective. Still, vaccinations are "best tool we have to prevent the flu," said Frieden. Flu season came early this year, and is predicted to drag on for a few more weeks—even though it may have already started to subside in states that experienced the outbreak first. 

If the word "epidemic" freaks you out, take a few breaths and look at the CDC's chart below for some perspective. The red line shows the current percentage of hospital vistors checking in for flu-like symptoms. As you can see, the flu seasons of 2009-2010 and 2003-2004 (grey and purple lines, respectively), had much higher hospital visitation rates. As we previously pointed out, this flu season may be a nasty one, but it's nothing especially worse than the bad seasons we've weathered in recent years.