1. Center for Infectious Diseases and Infection Control, Keio University School of Medicine
2. Department of Pediatrics, School of Medicine, Keio University
3. Department of Pediatrics, Fuji Heavy Industries LTD. Health Insurance Society General Ota Hospital
4. Department of Pediatrics, St. Marianna University School of Medicine Yokohama City Seibu Hospital
5. Kitasato University, Research Organization for Infection Control Sciences