‘Spreading fast': New, mutated flu strain has Chicago-area doctors ‘on guard'

Health officials in Illinois are warning of a new and unexpected mutation that could make for a "more serious flu season" as cases are already on the rise. The new variant, known as " [ Subclade K ][5] ," is part of the H3N2 parent group, or a type of Flu A. Stream NBC 5 for free, 24/7, wherever y...