Institution: | 1. State Key Laboratory for Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, National Institute for Communicable Disease Control and Prevention, Beijing, China;2. Department of Gastroenterology, Qilu Hospital of Shandong University, Shandong, China;3. Department of Gastroenterology, Peking Union Medical College Hospital, Beijing, China;4. Department of Gastroenterology, Peking University Third Hospital, Beijing, China |