How do polio vaccines stop paralysis?

Poliovirus enters through the mouth, multiplies in the gut, and in some cases spreads to the nervous system, where it can damage motor neurons and cause permanent paralysis. Vaccines interrupt this process by preparing the immune system to neutralize the virus early. The inactivated polio vaccine is injected, while the oral polio vaccine is live attenuated and especially useful for inducing intestinal immunity. Global vaccination campaigns led by WHO, UNICEF, Rotary, and other partners have cut polio cases by more than 99% since 1988. Only a few countries still report wild poliovirus transmission.