Author Contributions: Drs van Gils and Sanders had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: Hak, van Alphen, Sanders.
Acquisition of data: van Gils, Veenhoven, Rodenburg, IJzerman, Bruin.
Analysis and interpretation of data: van Gils, Veenhoven, Hak, Bogaert, van Alphen, Sanders.
Drafting of the manuscript: van Gils, Veenhoven, Hak, Bogaert, van Alphen, Sanders.
Critical revision of the manuscript for important intellectual content: van Gils, Veenhoven, Hak, Rodenburg, Bogaert, IJzerman, Bruin, van Alphen, Sanders.
Statistical analysis: van Gils, Hak, Bogaert.
Obtained funding: Sanders.
Administrative, technical, or material support: van Gils, Veenhoven, Rodenburg, IJzerman, Bruin.
Study supervision: Veenhoven, Sanders.
Financial Disclosures: Dr Veenhoven reported receiving grant support from GlaxoSmithKline and Wyeth for vaccine studies and consulting fees from GlaxoSmithKline. Dr Sanders reported receiving unrestricted grants from Wyeth and Baxter for research, consulting fees from Wyeth and GlaxoSmithKline, lecturing fees from Wyeth, and grant support from Wyeth and GlaxoSmithKline for vaccine studies. No other authors reported any financial disclosures.
Funding/Support: This work was supported by the Dutch Ministry of Health.
Role of the Sponsor: The Dutch Ministry of Health played no role in the study design and conduct of the study, in the data collection, management, analysis, and interpretation of the data, or in the preparation, review, or approval of the manuscript.
Additional Contributions: We thank the participating children and their families for their time and effort, the members of the research team for their invaluable dedicated work and support, and all cooperating organizations for their support.