About the Authors

Diane Gu

Affiliation The National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China

Yurong Mao

Affiliation The National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China

Zhenzhu Tang

Affiliation Guangxi Center of Disease Control and Prevention, Nanning, Guangxi, China

Julio Montaner

Affiliation BC Center for Excellence in HIV/AIDS, University of British Columbia, Vancouver, BC, Canada

Zhiyong Shen

Affiliation Guangxi Center of Disease Control and Prevention, Nanning, Guangxi, China

Qiuying Zhu

Affiliation Guangxi Center of Disease Control and Prevention, Nanning, Guangxi, China

Roger Detels

Affiliation Department of Epidemiology, UCLA Fielding School of Public Health, Los Angeles, CA, United States of America

Xia Jin

Affiliation The National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China

Ran Xiong

Affiliation The National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China

Juan Xu

Affiliation The National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China

Walter Ling

Affiliation Integrated Substance Abuse Programs, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States of America

Lynda Erinoff

Affiliation National Institute on Drug Abuse, National Institutes of Health, Bethesda, MD, USA

Robert Lindblad

Affiliation The EMMES Corporation, Rockville, MD, United States of America

David Liu

Affiliation National Institute on Drug Abuse, National Institutes of Health, Bethesda, MD, USA

Paul Van Veldhuisen

Affiliation The EMMES Corporation, Rockville, MD, United States of America

Albert Hasson

Affiliation Integrated Substance Abuse Programs, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States of America

Zunyou Wu

wuzy@263.net

Affiliation The National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China

Competing Interests

RL and PV are employees of the EMMES Corporation. The EMMES Corporation is contracted by NIDA to provide technical support to the study. This does not alter our adherence to PLOS ONE policies on sharing data and materials. The rest of co-authors declared no competing interests.

Author Contributions

Conceived and designed the experiments: YM ZW. Performed the experiments: DG YM ZT ZS QZ XJ RX JX. Analyzed the data: DG YM XJ. Contributed reagents/materials/analysis tools: DG. Wrote the paper: DG ZW. Interpret data and revision of manuscript: DG YM JM RD WL LE RL DL PV AH ZW.