Funding for this research was provided by:
Beijing Municipal Administration of Hospitals (DFL20150201)
National Natural Science Foundation of China (81570891)
National Health and Family Planning Commission of the People's Republic of China (2018ZX10721102)
Article History
Received: 31 May 2020
Accepted: 14 August 2020
First Online: 26 August 2020
Compliance with ethical standards
:
: The authors declare that they have no competing interests.
: This study was reviewed and approved by the institutional review board of the National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention.
: All participants signed written informed consent to participate in the study and allow their de-identified records to be included in this analysis.