1. Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
2. Office for Infection Control, Asan Medical Center, Seoul, South Korea
3. Department of Microbiology, Institute for Viral Diseases, Biosafety Center, College of Medicine, Korea University, Seoul, South Korea
4. Clinical Research Center, Asan Institute for Life Sciences, Asan Medical Center, Seoul, South Korea