1. 1Carman and Ann Adams Department of Pediatrics, Prevention Research Center, Wayne State University School of Medicine, Detroit, Michigan, USA
2. 2Guangxi Center for Diseases Control and Prevention, Nanning, Guangxi, China
3. 3Global Health Institute, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA
4. 4Guilin Center for Diseases Control and Prevention, Guilin, Guangxi, China
5. 5Beihai Center for Diseases Control and Prevention, Beihai, Guangxi, China