1. Children’s Outcomes Research, Children’s Hospital Colorado, Aurora, Colorado;
2. Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado;
3. National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia;
4. Department of Community and Behavioral Health, Colorado School of Public Health, Denver, Colorado; and
5. Division of General Internal Medicine, Denver Health, Denver, Colorado