| Affiliation: | 1. Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, , Boston, Massachusetts, USA;2. Influenza Division, Centers for Disease Control and Prevention, , Atlanta, Georgia, USA;3. Division of Infectious Diseases and Department of Laboratory Medicine, Children's Hospital Boston, , Boston, Massachusetts, USA;4. Department of Research and Evaluation, Kaiser Permanente Southern California, , Pasadena, California, USA;5. Kaiser Permanente Vaccine Study Center, , Oakland, California, USA;6. Epidemiology Research Center, Marshfield Clinic Research Foundation, , Marshfield, Wisconsin, USA;7. Group Health Research Institute, , Seattle, Washington, USA;8. Kaiser Permanente Northwest Center for Health Research, , Portland, Oregon, USA;9. HealthPartners Research Foundation, , Minneapolis, Minnesota, USA;10. Institute for Health Research, Kaiser Permanente Colorado, , Denver, Colorado, USA;11. Division of General Pediatrics, Children's Hospital Boston, , Boston, Massachusetts, USA |
