1. Department of Health Policy and Management, Johns Hopkins Bloomberg School of Public Health , Baltimore, Maryland , USA
2. Department of Pediatrics, Nara Prefecture General Medical Center , Nara , Japan
3. Department of International Health, Johns Hopkins Bloomberg School of Public Health , Baltimore, Maryland , USA
4. Institute for Vaccine Safety, Johns Hopkins Bloomberg School of Public Health , Baltimore, Maryland , USA
5. Department of Health, Behavior and Society, Johns Hopkins Bloomberg School of Public Health , Baltimore, Maryland , USA
6. Armstrong Institute for Patient Safety and Quality, Johns Hopkins School of Medicine , Baltimore, Maryland , USA
7. Department of Anesthesiology and Critical Care Medicine, Johns Hopkins School of Medicine , Baltimore, Maryland , USA