Earlier this summer, NPR reported on this very phenomenon, wherein mutant strains from the polio vaccine caused more paralysis than wild polio. Could it really be that a lab-altered version of a virus is more dangerous than the one found in nature? Absolutely. As Jason Beaubien reports, as of June 2017, there were more cases of child paralysis caused by the polio vaccine than the actual, wild-caught disease itself. At the time of his reporting, just six cases of "wild" polio, which is naturally occurring in the environment, had been reported worldwide.