Researchers at the University of Minnesota say seasonal flu shots prevent the flu in about 59 percent of adults. The flu shot is much more effective in kids working for 83 percent of children aged seven and under.
Dr. Richard Besser with ABC's 'Good Morning America' says it's difficult to determine the strain of flu each year.
"Flu vaccine makers have to guess before the flu season what they think that will be," Besser said. "Some years, it works quite well; other years, not so well, but beyond that, most of our vaccines are much more effective."
Researchers say the current vaccine is the best way to protect you from getting sick.