In 1918, Philadelphia didn't cancel an important parade in the midst of a pandemic. The results were devestating - CNN
In September 1918, Philadelphia held a planned Liberty Loan Parade to promote the government bonds that were being issued to pay for World War I.
But the parade took place when the pandemic commonly called the Spanish flu -- the H1N1 virus -- arrived in the city of 1.7 million people....
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Yet Philadelphia didn't cancel its Liberty Loan Parade, scheduled for just a little more than a week later. Meant to be a patriotic wartime effort, the parade went on as scheduled on September 28, bringing 200,000 Philadelphians together.
By October 1, there were 635 new cases in Philadelphia, according to UPenn.
Philadelphia was one of the hardest-hit US cities. More than 12,000 people died in six weeks, with about 47,000 reported cases, according to UPenn. By the six-month mark, about 16,000 had died and there were more than half a million cases.