Short answers, pulled from the story.
Approximately 75% of all polio infections produce no symptoms at all. This silent nature allowed the virus to spread through populations for thousands of years before humanity recognized it as a distinct medical condition.
Polio was first clinically described on the 2nd of May 1789 by the English physician Michael Underwood. He referred to the condition as a debility of the lower extremities.
The 1952 polio epidemic resulted in nearly 58,000 cases and 3,145 deaths. Additionally, 21,269 people were left with mild to disabling paralysis during this outbreak.
The inactivated polio vaccine known as the Salk vaccine was announced to the world on the 12th of April 1955. Jonas Salk developed the vaccine in 1952 at the University of Pittsburgh.
The last remaining region with wild polio cases remains the South Asian countries of Afghanistan and Pakistan. In 2021, a single case of wild polio was detected in Malawi and another in Mozambique in 2022.
Between 25 percent and 50 percent of individuals who have recovered from paralytic polio in childhood can develop post-polio syndrome. This condition involves new muscle weakness and extreme fatigue that appears decades after the acute infection.