1. Department of Research & Evaluation Kaiser Permanente Southern California Pasadena California USA
2. Department of Health Systems Science Kaiser Permanente Bernard J. Tyson School of Medicine
3. Respiratory Diseases Branch, National Center for Immunization and Respiratory Diseases, Division of Bacterial Diseases Centers for Disease Control and Prevention Atlanta Georgia USA
4. Center for Pediatric Clinical Effectiveness Children's Hospital of Philadelphia Philadelphia Pennsylvania USA
5. Division of Neonatology, Children's Hospital of Philadelphia University of Pennsylvania Philadelphia Pennsylvania USA
6. Department of Pediatrics Kaiser Permanente Manhattan Beach Medical Office Manhattan Beach California USA