The worst flu season in 15 years has left hundreds of thousands of Americans hospitalized while straining physicians’ offices and emergency departments.

Why it matters: The virus is causing more severe complications and hitting young children especially hard.

"The two predominant strains that are circulating right now are known to be more severe and have more severe outcomes, especially in high-risk patients," said Carol McLay, president of the Association for Professionals in Infection Control and Epidemiology.

Turns out having multiple infections run around wild does not “strengthen” our immune system. Who would have thought /s