Author Contributions: Dr Tseng 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: Tseng, Smith, Harpaz, Bialek, Jacobsen.
Acquisition of data: Tseng, Smith.
Analysis and interpretation of data: Smith, Harpaz, Bialek, Sy, Jacobsen.
Drafting of the manuscript: Tseng, Harpaz, Bialek.
Critical revision of the manuscript for important intellectual content: Smith, Harpaz, Bialek, Sy, Jacobsen.
Statistical analysis: Tseng, Smith, Harpaz.
Obtained funding: Jacobsen.
Administrative, technical, or material support: Tseng, Bialek, Jacobsen.
Conflict of Interest Disclosures: All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Drs Tseng, Smith, and Jacobsen and Ms Sy report having received research funding from Merck for other vaccine studies. Dr Jacobsen reports having served as an unpaid consultant for Merck Research Laboratories. Drs Harpaz and Bialek report no disclosures.
Disclaimer: The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the Centers for Disease Control and Prevention, US Department of Health and Human Services.