(CNN) The spread of the novel coronavirus has resulted in events being postponed or canceled across the country -- everything from the NBA and concerts to universities and schools has been affected.

It might be enough to make people wonder: Is all this necessary?

The answer is yes. Just look at Philadelphia in 1918, and the spread of the flu.

How the Spanish flu hit Philadelphia

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.

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