1. Westat Rockville Maryland USA
2. Helix San Mateo California USA
3. HealthPartners Institute Minneapolis Minnesota USA
4. Kaiser Permanente Center for Health Research Portland Oregon USA
5. Center for Biomedical Informatics Regenstrief Institute Indianapolis Indiana USA
6. School of Medicine Indiana University Indianapolis Indiana USA
7. Coronavirus and Other Respiratory Viruses Division, National Center for Immunization and Respiratory Diseases Centers for Disease Control and Prevention Atlanta Georgia USA
8. Vanderbilt University Medical Center Nashville Tennessee USA
9. Baylor Scott & White Health Temple Texas USA
10. Texas A&M University College of Medicine Temple Texas USA
11. Department of Biomedical Informatics Columbia University Irving Medical Center New York New York USA
12. New York Presbyterian Hospital New York New York USA
13. School of Medicine University of Colorado Anschutz Medical Campus Aurora Colorado USA
14. Division of Infectious Diseases and Clinical Epidemiology Intermountain Healthcare Salt Lake City Utah USA
15. Kaiser Permanente Vaccine Study Center Kaiser Permanente Northern California Division of Research Oakland California USA
16. Children's Minnesota Minneapolis Minnesota USA
17. Fairbanks School of Public Health Indiana University Indianapolis Indiana USA
18. Influenza Division, National Center for Immunization and Respiratory Diseases Centers for Disease Control and Prevention Atlanta Georgia USA