Text and Data Mining valid from 2020-03-05
Received: 10 June 2019
Accepted: 21 February 2020
First Online: 5 March 2020
Ethics approval and consent to participate
: All subjects provided written informed consent to participate in this study. The institutional review board of the National Center for AIDS/STD Control and Prevention (NCAIDS), Chinese Center for Disease Control and Prevention (China CDC) approved this study (ethical Approval Number: X140617334).
: Not applicable.
: The authors declare that they have no competing interests.