Don’t get these two similar but also very different viral infections wrong. Both affect your respiratory tract but their symptoms and, more importantly, severity, are different. The flu is much worse and it can lead to serious health problems such as pneumonia. You’d also feel a lot worse for longer if you had the seasonal flu. Staying in bed for days because your muscles hurt, you are running a high fever, and have a headache is common. Some people even need to be hospitalized. Between 3,000 and 49,000 people in the U.S. alone have died from complications caused by the flu, according to the CDC.