As autumn arrives in Chicago and children return to classrooms, public health officials are confronting a convergence of respiratory threats that rarely announce themselves so plainly in advance. Flu and COVID-19 cases are climbing in the familiar rhythm of seasonal gathering, while measles — a disease once thought tamed — has already exceeded last year's totals across Illinois, exposing immunization gaps in nine counties. The moment asks an old question anew: whether communities will act on what they know before the cost of inaction becomes visible.