Researchers began working on a polio vaccine in the 1930s, but early attempts were unsuccessful. An effective vaccine didn’t come around until 1953, when Jonas Salk introduced his inactivated polio vaccine (IPV).
The disease had first emerged in the United Sates in 1894, but the first large epidemic happened in 1916 when public health experts recorded 27,000 cases and 6,000 deaths—roughly a third in New York City alone.
Polio remains endemic in two countries Afghanistan and Pakistan.
Several key strategies have been outlined for stopping polio transmission: High infant immunization coverage with four doses of oral polio vaccine (OPV) in the first year of life in developing and endemic countries, and routine immunization with OPV and/or IPV elsewhere.
1894, first outbreak of polio in epidemic form in the U.S. occurs in Vermont, with 132 cases. 1908, Karl Landsteiner and Erwin Popper identify a virus as the cause of polio by transmitting the disease to a monkey.
The discovery by Karl Landsteiner and Erwin Popper in 1908 that polio was caused by a virus, a discovery made by inoculating macaque monkeys with an extract of nervous tissue from polio victims that was shown to be free of other infectious agents.
This means that there is no year-round transmission of poliovirus in the United States. Since 1979, no cases of polio have originated in the U.S. However, the virus has been brought into the country by travelers with polio. The last time this happened was in 1993.
Only three polio-endemic countries (countries that have never interrupted the transmission of wild poliovirus) remain— Afghanistan, Nigeria, and Pakistan. Without our polio eradication efforts, more than 17 million people who are currently healthy would have been paralyzed by the virus.
Paralysis is the most severe symptom associated with polio, because it can lead to permanent disability and death. Between 2 and 10 out of 100 people who have paralysis from poliovirus infection die, because the virus affects the muscles that help them breathe.
Polio does still exist, although polio cases have decreased by over 99% since 1988, from an estimated more than 350 000 cases to 22 reported cases in 2017. This reduction is the result of the global effort to eradicate the disease.
To date, there have been 94 wild poliovirus cases reported in 2019, compared to 33 in all of 2018. In addition, several African nations reported single cases of vaccine-derived polio: Chad, Benin, the Democratic Republic of the Congo, Ghana, Ethiopia, Togo, and Zambia.
The mortality rate for acute paralytic polio ranges from 5–15%. The paralysis can progress for up to one week. Permanent weakness is observed in two-thirds of patients with paralytic poliomyelitis.
Each summer, polio would come like The Plague. Beaches and pools would close — because of the fear that the poliovirus was waterborne. Children had to say away from crowds, so they often were banned from movie theaters, bowling alleys, and the like.