Funding for this research was provided by:
Shanghai Talent Development Fund (2017090)
Key Disciplines Construction Foundation of Health Commission of Shanghai Pudong New District of China (PDZX2017-25)
Project of Hundred Talents Pool in Shanghai University of Medicine & Health Sciences
First Online: 1 October 2020
Ethics approval and consent to participate
: Verbal informed consent was obtained from each subject. Our study did not involve any intervention in human participants. Individual information was de-identified prior to analysis. Strict confidentiality of individual data was practiced during the entire study. The verbal informed consent procedure and the surveillance protocol were approved by the ethical committee of Shanghai Pudong New Area Center for Disease Control and Prevention.
: Not applicable.
: The authors declare that they have no competing interests.