1. Department of AIDS/STD Control and Prevention, Guangzhou Center for Disease Control and Prevention, No. 1 Qide Road, Jiahe, Guangzhou, Guangdong,510440, China.
2. University of North Carolina Project-China, Guangzhou, China.
3. Lingnan Partners Community Support Center (GZTZ.ORG), Guangzhou, China.
4. School of Public Health, Sun Yat-sen University, Guangzhou, China.
5. Fielding School of Public Health, University of California Los Angeles, Los Angeles, United States of America.
6. Global Fund to fight AIDS, Tuberculosis and Malaria, Geneva, Switzerland.