In the late 19th and early 20th centuries, frequent epidemics saw polio become the most feared disease in the world. A major outbreak in New York City in 1916 killed over 2000 people, and the worst recorded US outbreak in 1952 killed over 3000. Salk was committed to equitable access to his vaccine, and understood that elimination efforts would not work without universal low- or no-cost vaccination. The vaccine was unbound from legal patents so people across the globe and across time can benefit - fairly.