Author Contributions: Dr Izurieta 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: Izurieta, Haber, Wise, Mink, Ball.
Acquisition of data: Izurieta, Braun.
Analysis and interpretation of data: Izurieta, Haber, Wise, Iskander, Pratt, Mink, Chang, Braun, Ball.
Drafting of the manuscript: Izurieta, Haber, Wise.
Critical revision of the manuscript for important intellectual content: Izurieta, Haber, Wise, Iskander, Pratt, Mink, Chang, Braun, Ball.
Statistical analysis: Izurieta, Chang.
Administrative, technical, or material support: Izurieta, Wise, Iskander, Braun, Ball.
Study supervision: Izurieta, Haber, Wise, Iskander, Pratt, Mink, Braun, Ball.
Financial Disclosures: None reported.
Funding/Support: The study was implemented by Food and Drug Administration (FDA) and Centers for Disease Control and Prevention (CDC) scientists and the only funds used were from CDC and FDA budgets. This study had no external sponsors.
Acknowledgment: We wish to thank the US Vaccine Adverse Event Reporting System (VAERS) staff, particularly Marla Sidey-Vener, RN, and Steve Gordon, PharmD, for assistance on VAERS reports follow-up; Elaine Miller, RN, Frank Destefano, MD, MPH, Walton Kim, MS, and Roseanne English (CDC), and Ann McMahon, MD, MSc, and Jane Woo, MD, MPH (FDA) for their helpful comments and discussion; and Scott Harper, MD, MPH, MSc, Alexander Klimov, PhD, ScD, and Nancy Cox, PhD (CDC), for their comments and for contributing information on their investigation of secondary transmission of the vaccine virus.