People line up every year to get an influenza or flu shot. But, experts say last year's formula didn't offer the best protection. 

"We created a good influenza vaccine last year and then, in the middle of the season, we had a new influenza viral strain come into the United States," said Dr. William Shaffner.  "That meant people were only partially protected. Partial protection changes a severe illness to a milder one. You might have gotten sick but you didn't have to be hospitalized. i'll take that as a good result," he said. 

The Centers for Disease Control and Prevention guidelines call for babies six months and older, up to age 19, to get an annual flu vaccine. 
Adults 50 years and older should also get the shot, along with pregnant women, those with chronic illnesses and caregivers. 

"This year as we look into our crystal ball, we actually anticipate not just one but three new influenza viral strains that will circulate in the United States," Dr. Shaffner said.  "That could mean a very bad influenza season." 

One more reason experts say to roll up your sleeve and get vaccinated.