1. aDivision of Research, Vaccine Study Center, Kaiser Permanente Northern California, Oakland, California
2. bDepartment of Research and Evaluation, Kaiser Permanente Southern California, Pasadena, California
3. cDepartment of Health Systems Science, Kaiser Permanente Bernard J. Tyson School of Medicine, Pasadena, California
4. dHealthPartners Institute, Minneapolis, Minnesota
5. eDepartment of Population Medicine, Harvard Medical School and the Harvard Pilgrim Health Care Institute, Boston, Massachusetts
6. fThe Center for Health Research, Kaiser Permanente Northwest, Portland, Oregon
7. gCenter for Clinical Epidemiology & Population Health, Marshfield Clinic Research Institute, Marshfield, Wisconsin
8. hInstitute for Health Research, Kaiser Permanente Colorado, Denver, Colorado
9. iKaiser Permanente Washington Health Research Institute, Seattle, Washington
10. jImmunization Services Division
11. kImmunization Safety Office, Centers for Disease Control and Prevention, Atlanta, Georgia