This year's dose is about 50 percent effective against the predominant flu strain, vastly outperforming last year's formulation.
Prevention is key—public health officials urge Americans to get an annual flu shot, to protect both yourself and those around you.
Two-thirds of confirmed cases in the U.S. have been caused by the dangerous H3N2 strain.
In a twist, the middle-aged were among those hardest hit, CDC says.
Don’t let your guard down: CDC expects to see high activity for several more weeks.
