How did World War 1 help intensify the spread of the Spanish Flu?

The war fostered influenza in the crowded conditions of military camps in the United States and in the trenches of the Western Front in Europe. The virus traveled with military personnel from camp to camp and across the Atlantic, and at the height of the American military involvement in the war, September-November 1918, influenza and pneumonia sickened 20%-40% of U.S. Army and Navy personnel. These high morbidity rates interfered with induction and training schedules in the United States and rendered hundreds of thousands of military personnel non-effective.

superpowergirl superpowergirl · Answer 2 · 2020-03-27T23:34:31+01:00

The great influenza pandemic of 1918-19, often called the Spanish flu, caused about 50 million deaths worldwide; far more than the deaths from combat casualties in the World War One (1914-18). In fact, it may have killed between 3% and 6% of the global population.

At the time, pandemic influenza was new to the world and only people exposed to milder forms of influenza in earlier flu seasons (usually winter) had partial protection against this more virulent form of the virus. And since it happened in the pre-antibiotic era, heavily infected patients were likely to die from viral pneumonia and complicating bacterial infections.