What are the symptoms of polio?
Up to about 95 percent of people infected with polio have no symptoms. However, infected persons without symptoms can still spread the virus and cause others to develop polio. About four to eight percent of infected persons have minor symptoms such as fever, sore throat, upset stomach, or flu-like symptoms and have no paralysis or other serious symptoms. About one to two percent of infected persons develop aseptic meningitis with stiffness of the back, back or legs, and in some persons increased or abnormal sensations. Symptoms typically last from two to ten days, followed by complete recovery. Less than 1 percent of polio cases result in paralysis. The risk of paralysis increases with age.
