1. School of Public Health, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan.
2. Department of Infectious Diseases, Taoyuan General Hospital, Department of Health, Taoyuan, Taiwan.
3. Fourth Division, Centers for Disease Control, Department of Health, Taipei, Taiwan.
4. Department of Public Health, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.