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 Links2023-02Lisa’s Family Photos2023-01The Lisa: Apple's Most Influential Failure - CHM2023-01OpenSFHistory Top Ten: The Bridges of Golden Gate Park - OpenSFHistory - Western Neighborhoods Project2023-01Consoles and Competition2023-01Why America Doesn’t Build What It Invents