1918 Spanish Flu

How (and how not) to battle flu -- When the Spanish flu reached the United States in the summer of 1918, it seemed to confine itself to military camps. But when it arrived in Philadelphia in September, it struck with a vengeance.

By the time officials there grasped the threat of the virus, it was too late. The disease was rampaging through the population, partly because the city had allowed large public gatherings, including a citywide parade in support of a World War I loan drive, to go on as planned. In four months, more than 12,000 Philadelphians died, an excess death rate of 719 people for every 100,000 inhabitants.

The story was quite different in St. Louis. Two weeks before Philadelphia officials began to react, doctors in St. Louis persuaded the city to require that influenza cases be registered with the health department. And two days after the first civilian cases, police officers helped the department enforce a shutdown of schools, churches and other gathering places. Infected people were quarantined in their homes.

Excess deaths in St. Louis were 347 per 100,000 people, less than half the rate in Philadelphia. Early action appeared to have saved thousands of lives.