Still, about 20 percent of the U.S. population is infected by influenza, resulting in 300,000 hospital stays and about 20,000 deaths a year. More than 90 percent of the deaths involve people over 65. Influenza rarely kills by itself. Instead, it causes complications, such as pneumonia, that can lead to death. Cold vs. fluCold vs. flu Viral infections bring similar symptoms for cold and flu victims.
Flu usually is more severe.