Flu vaccine ineffective for people 65 and older last winter
NEW YORK (AP) — The flu vaccine did a poor job protecting older Americans against the illness last winter, even though the vaccine was well-matched to the flu bugs going around.
The CDC calculates vaccine effectiveness from a sample of flu tests done on patients in five states.
Over the last ten winters, overall flu vaccine effectiveness has averaged about 46 percent.
Investigators are trying to figure out whether past flu vaccinations made a difference in how well the most recent flu shot worked, and whether there's a way to check more people to see how quickly the vaccine's protection is lasting.