Short answers, pulled from the story.
John A. Kolmer developed the live polio vaccine that caused paralysis and deaths in the autumn of 1935. This catastrophic failure halted all vaccine development for nearly two decades.
John Enders Thomas Weller and Frederick Robbins successfully cultivated the poliovirus in human tissue outside of the body in 1948. This discovery earned them the Nobel Prize in Physiology or Medicine in 1954.
The Salk vaccine was announced as safe and effective on the 12th of April 1955. Just a week later reports emerged that the Cutter Laboratories vaccine had not been properly inactivated leading to 260 cases of polio and 11 deaths.
Over 98 million Americans received one or more doses of polio vaccine that were contaminated with SV40 between 1955 and 1963. Subsequent large-scale studies found no increased incidence of cancer in persons who had received the contaminated vaccine.
The World Health Organization UNICEF and the Rotary Foundation launched a global effort to eradicate polio in 1988. This campaign reduced the number of reported polio cases from an estimated 350,000 in 1988 to just 33 in 2018.
The novel oral polio vaccine type 2 was granted emergency licensing in 2021 and full licensure in December 2023. This genetically modified vaccine has greater genetic stability than the traditional oral vaccine and is less likely to revert to a virulent form.