Question: how many years did it take to get a polio vaccine?
Answer: It was developed in 1961. OPV was recommended for use in the United States for almost 40 years, from 1963 until 2000. The results have been miraculous: Polio was eliminated from the United States in 1979 and from the Western Hemisphere in 1991. Since 2000, only IPV is recommended to prevent polio in the United States.