In 1955, epidemiologist Thomas Francis Jr. announced the results of a field trial of the polio vaccine that Jonas Salk had developPosted on Friday, May 28, 2021 6:12 AM‘The Last Time a Vaccine Saved America’TagsVaccinePolioHistoryRelated Links2022-01VFX Artifacts: The alpha channel and Alvy Ray Smith2022-01World's First Microprocessor2022-01The Epic of Collier Heights2022-01The Revolt That Almost Overthrew Slavery2022-01The Loss of an Icon: A Closer Look