Funding for this research was provided by:
Zhejiang Province Public Welfare Technology Application Research Project (LGF19H260010)
Medical Technology Program Foundation of Zhejiang, (2018KY730, 2018KY680)
Received: 28 October 2019
Accepted: 29 April 2020
First Online: 14 May 2020
Ethics approval and consent to participate
: The survey protocols, instruments, and the process for obtaining the informed consent for participants were approved by the Institutional Review Board of Ningbo Municipal CDC [March 4, 2016; Reference No. IRB201603]. All participants provided written informed consents prior to the surveys (for participants under 16 years old, their parents fill in informed consent form instead).
: Not applicable.
: The authors declare that they have no competing interests.