[ZeroGravitas]

I found out recently that "Spanish Flu" is so called because all the countries fighting in the war censored any mention of it happening in their camps, where it almost certainly originated.

From wikipedia:

"To maintain morale, wartime censors minimized early reports of illness and mortality in Germany, Britain, France, and the United States;[9][10] but papers were free to report the epidemic's effects in neutral Spain (such as the grave illness of King Alfonso XIII),[11] creating a false impression of Spain as especially hard hit[12]—thus the pandemic's nickname Spanish flu."

and

Investigative work by a British team led by virologist John Oxford[15] of St Bartholomew's Hospital and the Royal London Hospital identified a major troop staging and hospital camp in Étaples, France, as almost certainly being the center of the 1918 flu pandemic. A significant precursor virus, harbored in birds, mutated to pigs that were kept near the front.[16]