Although there hasn't been a case of polio caused by wild virus in the United States since 1979, there is still a risk of the virus coming into this country until the world is rid of polio. They can spread the virus by touch if they do not wash their hands after coughing or using the toilet. Food and liquids can be tainted this way. People who have not been immunized can get polio by eating tainted food or drinking tainted liquids. People with polio can spread the disease a few days before their symptoms start until about 6 days after.
Symptoms start about one to three weeks after a person is exposed.
There are vaccines to prevent polio. Before these vaccines were invented, thousands of people in the U.S. were paralyzed by the disease. Polio vaccine is helping to rid the world of polio. They are safe for most people. Very rarely, about once for every 2,400,000 doses of OPV, the live vaccine can cause polio.