1. Intensive Care Unit, Shenzhen Second People's Hospital the First Affiliated Hospital of Shenzhen University Shenzhen 518031 P. R. China
2. Shenzhen Center for Disease Control and Prevention Shenzhen 518055 P. R. China
3. Guangdong Provincial Key Laboratory of Pharmaceutical Bioactive Substances, Institute of Pharmaceutical Bioactive Substances, School of Basic Medical Sciences Guangdong Pharmaceutical University Guangzhou 510006 P. R. China
4. Key Laboratory of the Ministry of Health for Research on Quality and Standardization of Biotech Products National Institutes for Food and Drug Control Beijing 102629 P. R. China