Ask any child, a world without Walt Disney would be unimaginable. Born in December 1901, Walt was sixteen years old when he caught the 1918 pandemic influenza — and survived. A century has passed since the great 1918 pandemic, in which tens of millions died, the deadliest in history. When an anniversary of a major event comes round, we can ask what if the event were to occur today.
Catastrophe modelers can also reimagine the event being different from what it actually was. This counterfactual perspective leads to important insights into pandemic risk, which have only recently emerged from virological research.