Guangzhou Center for Disease Control and Prevention, Southern Medical University - Department of Epidemiology, Guangzhou Center for Disease Control and Prevention, Southern Medical University - Department of Epidemiology, Guangzhou Center for Disease Control and Prevention, Southern Medical University - Department of Epidemiology, Guangzhou Center for Disease Control and Prevention, Zhejiang University - State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Guangzhou Center for Disease Control and Prevention, Southern Medical University - Department of Epidemiology, Guangzhou Center for Disease Control and Prevention, Southern Medical University - Department of Epidemiology, Guangzhou Center for Disease Control and Prevention, Southern Medical University - Department of Epidemiology, Southern Medical University - Department of Epidemiology, Southern Medical University - Department of Epidemiology, Southern Medical University - Department of Epidemiology, Southern Medical University - Department of Epidemiology, Southern Medical University - Department of Epidemiology, Southern Medical University - Department of Epidemiology, Southern Medical University - Department of Epidemiology, Southern Medical University - Food Safety and Health Research Center, Guangzhou Center for Disease Control and Prevention, The Chinese University of Hong Kong (CUHK) - School of Public Health and Primary Care, Guangzhou Center for Disease Control and Prevention and Southern Medical University - Department of Epidemiology