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Notice to Readers: 50th Anniversary of the First Effective Polio Vaccine --- April 12, 2005

April 12, 2005, marks the 50th anniversary of the announcement that the polio vaccine, developed by Jonas Salk and his team of scientists at the University of Pittsburgh, worked. "Safe, effective, and potent" were the words used to announce to the world that an effective vaccine had been found against a disease that once paralyzed 13,000--20,000 persons each year in the United States.

In 1979, fewer than 25 years after introduction of the vaccine, the last indigenously acquired case of polio caused by wild poliovirus was detected in the United States; 15 years later, in 1994, the Western Hemisphere was certified polio-free.

Through support by the National Foundation for Infantile Paralysis (known today as the March of Dimes), Thomas Francis Jr. of the University of Michigan led the pioneering field studies of inactivated polio vaccine that led to the April 12, 1955, announcement. Approximately 1.8 million children from 217 areas of the United States, Canada, and Finland participated in the vaccine field studies. Thousands of health-care workers and lay persons volunteered to assist with the field studies, the largest ever in U.S. history. The National Foundation for Infantile Paralysis also supported the development work of Albert Sabin, whose oral polio vaccine (OPV) was licensed in 1961.

The Global Polio Eradication Initiative, spearheaded by the World Health Organization, Rotary International, UNICEF, and CDC, was begun in 1988. That year, an estimated 350,000 children were stricken with polio worldwide; in 2004, polio cases had decreased to approximately 1,200 cases globally. Although the Americas are polio-free, the disease still exists in some countries in Asia and Africa. Using the Sabin OPV, the Initiative continues to conduct immunization campaigns in those countries that have not been declared polio-free.

In recognition of the anniversary of the first effective polio vaccine, the Smithsonian's National Museum of American History will open a year-long exhibition, "Whatever Happened to Polio?" The exhibition will tell the story of the polio epidemic in the United States, the vaccine development, and current world efforts to stop transmission. Also highlighted will be stories of polio survivors and the influences they have had on society in the United States. Information about the exhibit is available at Information about polio disease, vaccine, and eradication efforts is available at

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