1. Division of Viral Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia
2. Epidemic Intelligence Service, Centers for Disease Control and Prevention, Atlanta, Georgia
3. Institute of Population Health Sciences, National Health Research Institutes, Zhunan, Taiwan
4. Division of Pediatric Infectious Diseases, Chang Gung Memorial Hospital at Linkou and Chang Gung University College of Medicine, Taoyuan, Taiwan
5. Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, Georgia
6. Centers for Disease Control, Taipei, Taiwan