1. 1Institute for Global Health, Vanderbilt University School of Medicine, Nashville, TN, USA
2. 2Department of Science and Research, Shandong Center for Disease Control and Prevention, Chengdu, China
3. 3Fengtai Disease Control and Prevention, Beijing, China
4. 4Institute for AIDS/STI Control and Prevention, Sichuan Center for Disease Control and Prevention, Chengdu, China
5. 5Department of Biostatistics and Epidemiology, School of Public Health, Shandon University, Jinan, China
6. 6Center for HIV/AIDS Control and Prevention, Center for Disease Control and Prevention
7. 7Department of Health, Washington DC, USA
8. 8Departments of Biostatistics
9. 9Preventive Medicine
10. 10Pediatrics, Vanderbilt University School of Medicine, Nashville, TN, USA