AdvertisementA Man Shed Live Polio Virus In His Stool For 28 YearsAugust 27, 2015Susan BrinkfacebookEmailNo trace of polio has been found in Nigeria since July 2014. Above, a child at a health clinic there is immunized. New findings about how long the polio virus can be excreted by some individuals make it clear that vaccine vigilance is critical. (NPR)