Author Contributions: Dr Lynch had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: Lynch, Blanton, Polyak, Barrett, Mintz.
Acquisition of data: Lynch, Blanton, Bulens, Polyak, Vojdani, Stevenson, Medalla, Barzilay, Joyce, Barrett, Mintz.
Analysis and interpretation of data: Lynch, Blanton, Polyak, Vojdani, Barzilay, Barrett, Mintz.
Drafting of the manuscript: Lynch, Polyak, Vojdani, Joyce, Mintz.
Critical revision of the manuscript for important intellectual content: Lynch, Blanton, Bulens, Polyak, Stevenson, Medalla, Barzilay, Barrett, Mintz.
Statistical analysis: Lynch, Blanton, Polyak.
Administrative, technical, or material support: Blanton, Bulens, Vojdani, Joyce.
Study supervision: Barrett, Mintz.
Financial Disclosures: None reported.
Additional Contributions: We thank the public health officials in state and local health departments and public health laboratories in all 50 states, the District of Columbia, and the US territories for their assistance in conducting typhoid fever surveillance.