Great Polio Epidemic

Summary

The 1916 polio epidemic struck 26 U.S. states, producing roughly 27,000 cases and 7,000 deaths, with New York City suffering the heaviest toll. Paradoxically, improved urban sanitation had left older populations without natural immunity acquired through early childhood exposure, making the disease far more dangerous than in prior eras.

Key Points

• Infection rates jumped from under 7.9 to 28.5 cases per 100,000; at the epidemic’s peak, a single week saw over 1,100 NYC cases
• Cleaner cities meant fewer infants were exposed early, so adults lacked immunity — the “sanitation paradox”
• Quarantine enforcement was class-based: poor and immigrant children faced forced hospitalization while wealthy families relocated
• The federal post-epidemic report confirmed quarantine had failed, but public anxiety persisted until vaccines arrived around 1960