1 Department of Epidemiology and Health Statistics, School of Public Health, Anhui Medical University, Hefei, Anhui 230032, China.
2 Department of Epidemiology and Health Statistics, School of Public Health, Anhui Medical University, Hefei, Anhui 230032, China; Anhui Provincial Children's Hospital/Children's Hospital of Anhui Medical University, Hefei Anhui, 230051, PR China.
3 College of Osteopathic Medicine, Kansas City University, 1750 Independence Ave, Kansas City, MO 64106, USA.
4 Infectious disease and international health, Dartmouth-Hitchcock Medical Center, 1 Medical Center Drive, Lebanon NH 03756, USA.
5 AMITA Health Saint Joseph Hospital Chicago, 2900 N. Lake Shore Drive, Chicago 60657, Illinois, USA. Electronic address: drsunchenyu@yeah.net.