Funding for this research was provided by:
the National Key Research and Development Program of China (2017YFE0103800)
National Institute of Allergy and Infectious Diseases (NIAID 1R01AI114310-01, NIAID K24AI143471, NIAID 5P30AI050410)
National Institute of Mental Health (R34MH119963)
National Major Science and Technology Projects of China (2018ZX10101-001-001-003)
the National Nature Science Foundation of China (81903371)
Received: 16 May 2019
Accepted: 8 January 2020
First Online: 15 January 2020
Ethics approval and consent to participate
: Eligible survey participants were invited to take part in the survey after indicating their informed consent online. The study protocol was approved by the ethics review committees at the Guangdong Provincial Centre for Skin Diseases and STI Control, the University of North Carolina at Chapel Hill, and the University of California, San Francisco.
: Not applicable.
: The authors declare that they have no competing interests.