1. Department of Epidemiology Vitalant Research Institute San Francisco California USA
2. Department of Pediatrics, Division of Hematology/Oncology UCSF Benioff Children's Hospital Oakland Oakland California USA
3. Rodeghier Consultants Chicago Illinois USA
4. Department of Pediatrics, Division of Hematology/Oncology, Vanderbilt‐Meharry Center for Excellence in Sickle Cell Disease Vanderbilt University Medical Center Nashville Tennessee USA