Polio has not been eradicated by vaccination, it is lurking behind a redefinition and new diagnostic names like viral or aseptic meningitis.......According to one of the 1997 issues of the MMWR, there are some 30,000 to 50,000 cases of viral meningitis per year in the United States alone. That's where all those 30,000 - 50,000 cases of polio disappeared after the introduction of mass vaccination