University of Michigan, Ann Arbor, MI 48109, United States
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The field trial results were announced at the University of Michigan on 12 April 1955, the date the announcement itself carries.[1]At Ann Arbor, Thomas Francis Jr announced the results of the largest medical field trial ever run - 1.8 million children - and pronounced Jonas Salk's polio vaccine safe, effective and potent. Church bells rang across the United States; within two years American cases had fallen by almost 90 per cent.
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