Funding for this research was provided by:
Korea Centers for Disease Control and Prevention
Article History
Received: 3 April 2020
Accepted: 3 June 2021
First Online: 15 June 2021
Declarations
:
: This study was approved by The Institutional Review Board of the Ewha Womans University School of Medicine, Seoul, Korea (SEUMC 2019–04-008). Consent to participate was not required, because this study did not involve human participant interactions and all data were publicly available and de-identified.
: Not applicable.
: The authors declare that they have no competing interests.