Received: 13 February 2021
Accepted: 17 May 2021
First Online: 29 May 2021
: The study protocol was approved by the Institutional Review Board of the University of Hong Kong/Hospital Authority Hong Kong West Cluster (UW17–540). The study was conducted according to the relevant guidelines and regulations. All respondents provided verbal informed consent for their participation.
: Not applicable.
: On behalf of all authors, the corresponding author states that there is no conflict of interest.