Britannica
Sources used in this answer
How often does poliovirus infection lead to paralysis?
Created from Britannica articles
using AI.
AI can make mistakes, so verify using Britannica articles.
polio
A health care worker giving a polio vaccine to a child in Katsina state, Nigeria, 2014.
Paralysis is an uncommon complication of poliovirus infection, as most infected individuals experience no symptoms at all.12
While estimates vary, it is generally reported that approximately 1 in 200 people infected with polio develops flaccid paralysis. Other clinical assessments suggest that the incidence may be as low as 1 in 1,000, emphasizing that paralysis is not the typical outcome of the infection.12
In cases where the virus invades the central nervous system, it can destroy motor neurons in the spinal cord and brainstem, which disrupts the signals required for muscle contraction. When paralysis occurs, it can be permanent if the nerve cells are destroyed, as these cells cannot regenerate.1