1. Kaiser Permanente Vaccine Study Center, Oakland, California
2. Institute for Health Research, Kaiser Permanente Colorado, Denver
3. Center for Health Research, Kaiser Permanente Northwest, Portland, Oregon
4. Kaiser Permanente Washington, Seattle
5. Center for Clinical Epidemiology & Population Health, Marshfield Clinic Research Institute, Marshfield, Wisconsin
6. Department of Research and Evaluation, Kaiser Permanente Southern California, Pasadena
7. Immunization Safety Office, Centers for Disease Control and Prevention, Atlanta, Georgia