1. Tianjin Centers for Disease Control and Prevention, Tianjin, People’s Republic of China
2. National Center for AIDS/STD control and prevention, China CDC, Beijing, People’s Republic of China
3. GAP program office of U.S CDC, Beijing, People’s Republic of China
4. Tianjin HongQiao district Centers for Disease Control and Prevention, Tianjin, People’s Republic of China
5. Tianjin ShenLan Public Health Counseling Service Center, Tianjin, People’s Republic of China
6. Department of Health Behavior & Health Education, University of Michigan, School of Public Health, Ann Arbor, MI, USA