Worst of bad US flu season finally over as illnesses decline
WATCH: ABC News' David Kerley goes inside the National Institutes of Health headquarters in Bethesda, Maryland, where scientists are working to create a universal vaccine against the influenza virus.

The worst of the nation's nasty flu season is finally over.


While the peak may have passed, the season isn't finished yet. Reports of flu remained widespread in 45 states, the Centers for Disease Control and Prevention reported.

"The season's not over but we're definitely on the downward trend right now," said Dr. Anne Schuchat, the CDC's acting director.



Making a bad year worse, this year's flu vaccine didn't work very well and health officials are trying to figure out why it did so poorly.



Amber Smith, a recruiter for a furniture store chain in Charlotte, North Carolina, thought she didn't have to worry about the flu after a wave of illnesses that hit her company's warehouse in January and February seemed to fade. But she started to feel sick Monday and found out she had the flu. She hadn't gotten a flu shot; her boyfriend did and he hasn't been sick.

"I feel like my head weighs 20 pounds," said Smith, who tried to go to work Friday, but was sent home after a morning meeting. "But my throat isn't as sore. I feel like the flu is running its course."