1. Department of Pediatrics, University of California, Los Angeles, Los Angeles, California, United States
2. Department of Medicine, University of California, Los Angeles, Los Angeles, California, United States
3. Department of Neurology, University of California, Los Angeles, Los Angeles, California, United States
4. Department of Pathology & Laboratory Medicine, University of California, Los Angeles, Los Angeles, California, United States
5. Department of Medicine Statistics Core, University of California, Los Angeles, Los Angeles, California, United States
6. Acute Communicable Disease Control, County of Los Angeles Public Health, Los Angeles, California, United States