Prevalence. Data regarding the incidence and prevalence of post-polio syndrome are variable. Codd and colleagues (Codd et al 1985) found a prevalence of post-polio syndrome of 22.4%, but a repeat study from the same institution found a prevalence of 64% (Windebank et al 1991). The 1987 National Health Interview Survey estimated that about half of the 1.63 million people in the United States who survived acute poliomyelitis had new late effects (Bruno 1991). Another study from 1987 found a prevalence of 42% (Speir et al 1987); Ramlow and colleagues (Ramlow et al 1992) found a prevalence of 28.5%. More recent self-reporting surveys have found an even higher prevalence of new weakness: 53%, 58%, 85%, respectively (Wekre et al 1998; Ivanyi et al 1999; Kumakura et al 2002). The large number of cases now being seen relate to the large epidemics of poliomyelitis that occurred in the United States in the 1940s and 1950s (Jubelt and Cashman 1987). Bertolasi and colleagues report that female gender, the presence of respiratory disturbance during the acute phase of polio, and the use of orthoses and aids during the recovery and stabilization are independent risk factors for post-polio syndrome in their studied population (Bertolasi et al 2012).
Delay in onset of post-polio syndrome. The delay in onset from acute poliomyelitis to post-polio syndrome ranges from 8 to 71 years in various series (Jubelt and Cashman 1987). The more severe the acute polio, the earlier new symptoms are likely to occur (Halstead et al 1985). In various series the average interval is about 35 years (Halstead et al 1985; Jubelt and Cashman 1987; Ramlow et al 1992; Kidd et al 1997).