Despite the name, the flu in question didn't actually originate in Spain -- the real patient zero was probably in France, Kansas, or Canada -- but gained the moniker because Spain was the only country not lying about the pandemic. The rest of the world, not wanting to demoralize their painfully dying troops, simply closed their eyes, stuck their fingers in their ears, and pretended that all the soldiers huddled together in trenches and all the international travel everyone was doing in order to shoot bullets into each other wasn't exacerbating the problem.
Anyway, because the war and the flu were so intrinsically linked -- and because of, y'know, all the lying -- memorials and writing on the subject are actually fairly scarce. Even though flu victims outweighed dead soldiers by a heavy margin, the war got all the press, leaving little evidence of the infection behind. Even when it was all over, the involved countries were so concerned with "moving on" from tragedy that memories of the pandemic -- especially cultural ones -- were all but buried.
Enter Edvard Munch. The Norwegian painter, famous for "The Scream," was far from a one-hit wonder -- he was remarkably productive throughout his life, even when he, himself, was suffering from the Spanish Flu in 1919. Instead of wallowing (or even resting and isolating like he probably should have) he built himself a new studio, put on an exhibit in New York, and painted the slightly less famous "Self Portrait with the Spanish Flu."