1. Department of Infectious Diseases, Children's Hospital of Fudan University, Shanghai 201102, China
2. Institut Pasteur Shanghai, Chinese Academy of Sciences, Shanghai 200025, China
3. Department of Infectious Diseases & Gastroenterology, Children's Hospital of Chongqing Medical University, Chongqing 400014, China
4. Department of Infectious Diseases, Guangzhou Women and Children's Medical Center, Guangzhou 510120, China
5. Pediatric Department of Shantou University Medical College, Shantou 515041, China