The announcement of the polio vaccine's safety and effectiveness was on April 12, 1955, by Dr. Thomas Francis, Jr., of the University of Michigan, the monitor of the test results. Within minutes of his announcement to the audience of scientists and reporters, news of the event was carried coast to coast by wire services and radio and television newscasts. When the vaccine was announced as successful, therefore, it led to spontaneous celebrations across the United States. It was the world's first successful polio vaccine, declared “safe, effective, and potent.” It was possibly the most significant biomedical advance of the past century.