1. 1University of Washington, Department of Pediatrics, Seattle, WA
2. 2Wake Forest University School of Medicine, Winston-Salem, NC
3. 3Centers for Disease Control and Prevention, Atlanta, GA
4. 4University of Colorado Denver, Aurora, CO
5. 5University of North Carolina at Chapel Hill, Chapel Hill, NC
6. 6University of Cincinnati College of Medicine, Cincinnati, OH
7. 7University of South Carolina, Columbia, SC
8. 8Kaiser Permanente Southern California, Pasadena, CA
9. 9Medpace Reference Laboratories, Cincinnati, OH