Author Contributions: Dr Omer 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: Omer, Pan, Halsey, Stokley, Moulton, Navar, Pierce, Salmon.
Acquisition of data: Omer, Pan, Halsey, Stokley, Moulton, Navar, Pierce, Salmon.
Analysis and interpretation of data: Omer, Pan, Halsey, Stokley, Moulton, Navar, Pierce, Salmon.
Drafting of the manuscript: Omer, Pan, Halsey, Moulton, Navar, Pierce, Salmon.
Critical revision of the manuscript for important intellectual content: Omer, Pan, Halsey, Stokley, Moulton, Navar, Salmon.
Statistical analysis: Omer, Pan, Moulton.
Obtained funding: Salmon.
Administrative, technical, or material support: Halsey, Stokley, Navar, Salmon.
Study supervision: Salmon.
Financial Disclosures: Dr Halsey reports that he has received research grants from Sanofi Pasteur and GlaxoSmithKline for the study of vaccines in Guatemala and served as a consultant to Merck and Chiron on vaccine issues. Dr Moulton reports that he worked on 2 studies for which Sanofi Pasteur donated vaccine and that he received approximately $25 000 for a travel/study grant from Sanofi Pasteur. Drs Halsey and Moulton have received compensation for testimony for the US Department of Justice regarding several vaccine compensation cases. The other authors report no financial disclosures.
Funding/Support: This research was partially funded by grant UIP000032A from the Centers for Disease Control and Prevention (CDC). The state policies section of this article did not receive external funding from any source.
Role of the Sponsor: The CDC had no role in the design and conduct of the study; management, analysis, and interpretation of the data; and preparation of the final manuscript. The CDC collected the data on state exemption rates and pertussis cases and approved the final manuscript as is the case with all CDC authors.
Disclaimer: The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the CDC, US Department of Health and Human Services.
Acknowledgment: We would like to thank Pamela Srivastiva, MS, from the CDC, for providing state pertussis incidence data, Angela Myrick, MPH, from the CDC, for obtaining state exemption data, and Tina Proveaux, BS, from the Institute for Vaccine Safety, Johns Hopkins Bloomberg School of Public Health, for her help in editing and formatting the manuscript. None of these individuals received any financial compensation for their contributions.