1. Department of Pediatric Emergency, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong 510623, P.R. China
2. Department of Pediatric Neurology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong 510623, P.R. China
3. Paediatric Intensive Care Unit, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi 530021, P.R. China
4. Guangdong Provincial Institution of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, Guangdong 511430, P.R. China