Thesis:
There are many diseases all over the world. In the 1950`s The poliomyelitis (polio) disease affected ten of thousands of Americans for each year. The polio disease is known for attacking the central nervous system, which leads its victims body parts paralyzed and in some occasions there whole body would be paralyzed too. Then in 1955 John Salk introduced his vaccine witch was one of the biggest medical advances in american history.
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