1. School of Public Health, Zhejiang University School of Medicine , Hangzhou 310058 , P.R. China
2. National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Key Laboratory for Medical Virology, National Health Commission , Beijing 102206 , P.R. China
3. School of Public Health (Shenzhen), Sun Yat-sen University , Guangzhou 510275 , P.R. China
4. School of Public Health (Shenzhen), Shenzhen Campus of Sun Yat-sen University , Shenzhen 518107 , P.R. China
5. Institute of Pathogen Biology, Chinese Academy of Medical Science & Peking Union Medical College , Beijing 100730 , P.R. China