1. Department of Obstetrics and Gynecology; Beijing Youan Hospital, Capital Medical University; Beijing China
2. Department of Infectious Diseases; Beijing Youan Hospital, Capital Medical University; Beijing China
3. Center for Major Infectious Diseases; Beijing Youan Hospital, Capital Medical University; Beijing China
4. Division of Gastroenterology and Hepatology, Department of Medicine; NYU Langone Medical Center, New York University School of Medicine; New York USA