Author Contributions: Dr Grijalva 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: Grijalva, Nuorti, Griffin.
Acquisition of data: Grijalva.
Analysis and interpretation of data: Grijalva, Nuorti, Griffin.
Drafting of the manuscript: Grijalva.
Critical revision of the manuscript for important intellectual content: Grijalva, Nuorti, Griffin.
Statistical analysis: Grijalva.
Obtained funding: Grijalva, Griffin.
Administrative, technical, or material support: Nuorti, Griffin.
Financial Disclosures: Drs Grijalva and Griffin reported receiving lecture fees and negotiating potential research support from Wyeth. Dr Griffin reported receiving grant support from MedImmune and Pfizer. Dr Nuorti reported no disclosures.
Funding/Support: This study was funded by the Centers for Disease Control and Prevention (CDC) through Cooperative Agreements with the Association for Prevention Teaching and Research (TS-1392 and TS-1454). Dr Grijalva is supported by a CDC career development award (K01 CI000163).
Role of the Sponsor: An investigator from the CDC participated in the design and conduct of the study; in the analysis and interpretation of the data; and in the preparation, review, and approval of the manuscript.
Disclaimer: The findings and conclusions in this article are those of the authors and do not necessarily represent the views of the CDC.
Additional Contributions: We thank CDC investigators Cynthia G. Whitney, MD, MPH, and Lauri A. Hicks, DO, MPH, for critical, noncompensated review of the manuscript.