Seasonal peaks of viral respiratory illnesses are common during late summer and early fall and have often been attributed to human rhinovirus. In the fall of 2014, the number of children hospitalized with severe lower respiratory symptoms and asthma suddenly increased, and the children tested positive by sequencing for enterovirus D68 (EV-D68). As the outbreak unfolded, a possible association was also observed between EV-D68 infection, polio-like acute flaccid paralysis, and cranial neuropathy in children.