Is there a way to get the First World War to last long enough so that the Spanish flu epidemic would be breaking out across the world simultaneous with heavy fighting in Europe? IOTL, operations were winding down as the flu began to spread, so what I'm looking for is continued heavy actions and hostilities occurring concurrent with spikes in the number of infected individuals. I imagine it'd be sort of tricky, as to prolong the war, you might need to delay US entry, while the flu itself might've originated in the American Midwest (that's a big "might have" since data and records are too sketchy for scholars to pin down the exact geographical origin of the virus).