There are two types of polio vaccine (a medicine that is given to prevent polio). One is known as an inactivated polio vaccine (IPV); this type contains no live poliovirus. It is given as an injection in the arm or leg, depending on the person's age. The other type is a live oral vaccination, which contains live but weakened poliovirus. In the United States, the oral vaccine was discontinued in 2000 due to the risk of a rare but serious reaction.
Both vaccinations are highly effective in producing immunity to poliovirus and protection from paralytic poliomyelitis. Approximately 90 percent or more of vaccination recipients develop protective antibodies to all three poliovirus types after two doses, and at least 99 percent are immune following three doses.