This year's flu vaccine is better than nothing but not by much. The CDC said Thursday that the shot only reduces a person's chance of having to go to the doctor for the flu by 23 percent. "Commonly, it's been closer to 60 percent," said Brendan Flannery, an epidemiologist in the CDC's influenza division. This year's vaccine is considered to have one of the lowest success rates of the past decade because experts didn't correctly predict the flu strains that would make people sick. By the time flu season hit, two-thirds of H3N2 viruses making people sick with the flu were not included in the vaccine.