In this study, we investigated the causes of JE recurrence. Methods and Findings: All JE cases were laboratory-confirmed by detecting the JEV-specific IgM antibody with an IgMcapture enzyme-linked immunosorbent assay (ELISA). All were children between 2 months and 9 years of age with a median age of 2 years. Of the 31 cases, 9 had received one or two doses of the JEV vaccine, 11 had not been immunized previously with the JEV vaccine, and 11 had an unclear immunization history.
