Did world war one play any role in the 1918 swine flu spreading so much?

Yes, WWI had a huge effect on the spread of the Spanish Flu. Because there were huge numbers of people moving around the world (from North America to Europe, Europe to Australia, so on and so forth) the Spanish Flu could move around much quicker. However, because the modern world is so global, the same problems occured with H1N1. People can jump on a plane and be across the world in 10 hours, so H1N1 could have spread much quicker and over a larger distance than the Spanish Flu did. And the Spanish Flu could've stopped WWI, or prevented it from going on further just because of how many soldiers were dying due to sickness rather than injury in war.