Poliomyelitis (Polio) is a very Disease Surveillance caused by a virus that lives in the throat and intestinal tract and invades the nervous system. It is spread by person-to-person contact and only affects humans. Polio used to be very common in the United States and caused severe illness in thousands of people before the polio vaccine was introduced in 1955. The majority of people who are infected with the polio virus show no symptoms, however less than 1% of cases do develop paralysis that may result in permanent disability or even death. The last case of naturally occurring polio in the United States was in 1979. The only vaccine that is currently used in the United States is the inactivated poliovirus vaccine (IPV). Please see the vaccine information statement below (VIS).