We defined a typhoid fever occurrence primarily as a report of at least 1 episode of culture-confirmed typhoid fever where Salmonella Typhi was isolated at a given space and time excluding any duplicate reports from the same cohort. Reports of typhoid fever confirmed through serologic tests (e.g., Widal test or ELISA) or PCR, or suspected clinically (e.g., ileal perforation), were also included for secondary analysis. For imported cases, we assumed that the typhoid episode occurred in the country in which the infection was presumed to have been acquired (according to the report). If the imported cases led to local transmission, we assumed that typhoid occurred in both countries. Outbreaks were defined according to the author of the respective study.