In late August 1918, the first cases of a severe respiratory illness reached Philadelphia. By September 17, the city's health department had logged its first cases among civilians rather than servicemen; two days later, the Naval Hospital took in four hundred more sailors sick with the same disease in a single three-day stretch. Wilmer Krusen, the city's director of public health, told residents the outbreak would stay contained as long as new cases were isolated, and that there was little reason to expect many deaths.
On September 21, the city's Board of Health made influenza a legally reportable disease, a step officials took specifically so they could track the epidemic's spread more accurately. That same year, the U.S. Public Health Service's own weekly disease bulletin in Washington ran a standing line above its case tables stating why such laws exist. Philadelphia now had the means to answer that question about itself.
A week later, on September 28, some two hundred thousand people packed Broad Street for the Fourth Liberty Loan Parade, a war-bond rally Krusen lacked the legal authority to cancel; that power belonged to the mayor, who let it go ahead. Within days the city's hospitals were full. On October 3, the state health commissioner closed theaters, saloons and other gathering places statewide, and Philadelphia's own board closed its schools and churches the same day.
The case reports the city had just made mandatory kept arriving anyway: 1,480 new cases on October 5, and by October 7 the count stood at 5,561. On October 8, with new cases just beginning to level off, Krusen told reporters the epidemic had already reached its crest, and the Inquirer ran an editorial waving off further alarm. His own department's count told a harder story. New cases stayed in the thousands a day; undertakers fell behind, the city briefly suspended its death-certificate requirement, and gravediggers had to be recruited. On October 15 alone, ten truckloads of bodies went from the city morgue to the potter's field. On October 20, twelve days after Krusen's statement, the city still logged more than 1,300 new cases and 606 deaths. Not until October 30, with new cases down to 125, did anything reopen.
St. Louis saw its first civilian case on October 5 and closed its schools, churches and theaters within two days; Philadelphia took sixteen. A later study of both cities' case and death records found that St. Louis's peak weekly excess pneumonia-and-influenza death rate, while its own restrictions stayed in place, ran to 31 per 100,000 people, against 257 in Philadelphia; the same study found mortality in St. Louis climbed again once those restrictions were lifted in mid-November. Even so, its cumulative excess-mortality rate over the full sixteen weeks studied was roughly half of Philadelphia's. Both cities were counting the same disease under the same kind of law Philadelphia itself had just passed. Only one acted on the count before the worst of it arrived.
A trend can turn before a crisis is over. Three weeks after Philadelphia's health director called the peak, the city was still digging graves for it.