Effectiveness of Salk Vaccine in Reducing Nonparalytic Poliomyelitis in a Large Urban Epidemic

IN the 1954 field trial with poliomyelitis vaccine1 and in subsequent outbreaks of poliomyelitis2 3 4 5 6 the Salk vaccine was shown to be highly effective in reducing the incidence of paralytic poliomyelitis. Although it might be expected theoretically, evidence for a comparable effectiveness against nonparalytic poliomyelitis was not described.Kansas City, Missouri, had a severe poliomyelitis epidemic in 1959 that was carefully investigated. Etiologic studies were performed in four fifths of the cases. The majority of the reported paralytic and nonparalytic cases were proved to be due to poliovirus Type 1 infection. Other enterovirus infections were associated with the aseptic-meningitis syndrome in . . .