Does The Flu Shot Work? Effectiveness Of Vaccine Depends On Who You Are, Seasonal Trends

The seasonal flu shot is advertised in pharmacies, doctors' offices and billboards across the U.S. and is promoted as a way to keep the virus at bay. While there's evidence that the vaccine has led to significantly fewer hospitalizations during past flu seasons, seasonal flu epidemics are characteristically different from one year to the next, and getting pricked won't guarantee a symptom-free winter.