Funding for this research was provided by:
Zhejiang Provincial Medical Science Project (2020RC049, 2020388945)
Major Science and Technology Project of Zhejiang Province Health Commission (WKJ-ZJ-2112)
Received: 14 March 2021
Accepted: 6 September 2021
First Online: 7 October 2021
: The study was approved by Ethics Committee of Zhejiang Provincial Center for Disease Control and Prevention (No. 2020-009). Written consent was obtained from each participant. The data used in this study was anonymised before its use. The non-anonymous raw data were only stored in the designated computers managed by data keeper who was trained and appointed by Institutional Review Board (IRB). Permission should be granted from IRB before accessing the raw data.
: No applicable.
: All authors declare no competing interests.