Epidemiology
Post-polio syndrome occurs in approximately 25–50% of people who survive a poliomyelitis infection. On average, it occurs 30–35 years afterwards; however, delays of between 8–71 years have been recorded. The disease occurs sooner in persons with more severe initial infection. Other factors that increase the risk of postpolio syndrome include increasing length of time since acute poliovirus infection, presence of permanent residual impairment after recovery from the acute illness, and female sex.
Post-polio syndrome is documented to occur in cases of nonparalytic polio (NPP). One review states late-onset weakness and fatigue occurs in 14% to 42% of NPP patients.
Read more about this topic: Post-polio Syndrome