Fig. 1: Infant selection flowchart.

Hospital 1, the First Affiliated Hospital of Sun Yatsen University. The other 5 hospitals are: Shenzhen Children’s Hospital, Fujian Provincial Maternity and Children’s Hospital, Children’s Hospital of Zhejiang University School of Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology and West China Hospital, Sichuan University.