The Day the World Held Its Breath in Ann Arbor — and Polio Was Beaten

For the first half of the 20th century, polio terrified American parents. It paralyzed tens of thousands of children a year and put them in iron lungs. Then, on April 12, 1955, the world found out whether a vaccine could stop it — and the announcement came from Ann Arbor, Michigan.

At the University of Michigan’s Rackham Auditorium, Dr. Thomas Francis Jr. stepped up to deliver the verdict on the largest medical field trial in history. Per the University’s official press release, “At a meeting of over 500 scientists and physicians and before the penetrating eyes of cameras and powerful spotlights, Dr. Francis spoke.” Exactly 1,829,916 children — across the U.S., Canada, and Finland — had taken part. His verdict, in the words of that release: the Salk vaccine “has been proved to be up to 80–90 percent effective in preventing paralytic polio.”

There’s a beautiful Michigan thread here. The vaccine’s creator, Jonas Salk, had done postgraduate training under Francis at U-M, where Francis taught him the methods of vaccine development. When the results were announced, church bells rang and people wept. As one historian recounted, autoworkers in Detroit and garment workers in New York stopped and cried with relief.