that was ONE YEAR after they started developing the vaccine. "Salk tested his experimental killed-virus in 1953"
One year later after those tests, another 1.6 million were tested in canada, on April 26, 1954.
A year after that the vaxine was litreally annoucned with a 2 year study period: With these words on April 12, 1955, Dr. Thomas Francis Jr., director of the Poliomyelitis Vaccine Evaluation Center at the University of Michigan School of Public Health, announced to the world that the Salk polio vaccine was up to 90% effective in preventing paralytic polio.
Dr. Francis made the announcement to a crowd of scientists and reporters at the University of Michigan's Rackham Auditorium, concluding his two-year national field trials of the poliomyelitis vaccine developed by his former student, Jonas Salk.
|