Funding for this research was provided by:
Korea Centers for Disease Control and Prevention (4834-303)
Received: 18 March 2020
Accepted: 30 June 2020
First Online: 6 July 2020
Ethics approval and consent to participate
: All experimental procedures were approved by the institutional review boards of Korea Centers for Disease Control and Prevention (Ethics number: 2016-05-02-P-A).
: Not applicable.
: The authors declare that they have no competing interests.