The oral polio vaccine (OPV), which contains live but weakened poliovirus, was licensed in 1961. It became the vaccine of choice in the United States and most other countries of the world as cases of polio disease continued to drop following its introduction. Because a safer alternative (an enhanced-potency inactivated polio vaccine) became available in 1998, oral polio vaccine is no longer used in the United States.
Oral polio vaccine (OPV) is a vaccine that contains live but weakened poliovirus. OPV is highly effective in polio prevention. However, because of the risk of a rare but serious condition called vaccine-associated paralytic poliomyelitis, OPV use in the United States was discontinued in 2000.
A 1916 polio epidemic in the United States killed 6,000 people and paralyzed 27,000 more. In the early 1950s, there were more than 20,000 cases of polio each year.
The first polio vaccine was licensed in 1955. This polio vaccine was an inactivated polio vaccine (IPV), meaning it did not contain any live poliovirus. By 1960, the number of cases had dropped to about 3,000. In 1961, an oral polio vaccine was licensed. As the number of cases of polio disease continued to drop after its introduction, it became the vaccine of choice in the United States and most other countries of the world.
In 1979, the last cases of paralytic poliomyelitis caused by wild poliovirus in the United States occurred. The success of polio vaccination in the United States and other countries sparked a worldwide effort to eliminate polio.
In 1998, an enhanced-potency inactivated polio vaccine became available. Because OPV can cause a rare but serious reaction called vaccine-associated paralytic poliomyelitis, it was recommended that OPV not be used. In 2000, the use of OPV in the Unites States was discontinued.