1. State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.
2. School of Public Health, Qingdao University, Qingdao, China.
3. Shanxi Provincial Center for Disease Control and Prevention, Taiyuan, China.
4. Yangquan Center for Disease Control and Prevention, Yangquan, China.
5. School of Basic Medicine, Qingdao University, Qingdao, China.