The influenza pandemic of 1918-19 killed between 50 and 100 million people around the world, more than died in the battles of World War I. In the United States, the hardest-hit city was Philadelphia, where the spread of the disease was spurred by what was meant to be a joyous event: a parade.
Writing in Pennsylvania History: A Journal of Mid-Atlantic Studies, the historian Thomas Wirth explains what happened: “On September 28, despite the increased infiltration of the disease among the civilian population, a rally for the Fourth Liberty Loan Drive proceeded with minimal debate about the repercussions for public health.” The head of Philadelphia’s Naval Hospital told the Public Ledger in the days before the parade: “There is no cause for further alarm. We believe we have it well in hand.” So, the parade went forward. “In the streets of downtown Philadelphia 200,000 people gathered to celebrate an impending allied victory in World War I. Within a week of the rally an estimated 45,000 Philadelphians were afflicted with influenza.”
In six weeks, 12,000 were dead. The smell of bodies left to rot in homes while they waited to be removed permeated the streets. The spread of the virus was exacerbated by existing conditions in the city: a booming population drawn by the wartime industries, a density of housing, and a lack of sanitation services and safe drinking water in these working-class neighborhoods.