Funding for this research was provided by:
The national Key Research and Development Program of China (2018YFC1002200)
The Special Foundation for State Basic Research Program of China (2014FY110700)
Received: 22 February 2020
Accepted: 23 July 2020
First Online: 30 July 2020
Ethics approval and consent to participate
: The study protocol has received permission from the NHC, and all licensed medical institutions completed the questionnaires accordingly; this process did not involve individual information. According to the Council for International Organizations of Medical Sciences, it meets the conditions of ethical exoneration, and ethics approval and consent to participate were not necessary in the study.
: Not applicable.
: The authors declare that they have no competing interests.