Funding for this research was provided by:
Seoul National Hospital (0420071070)
Received: 29 October 2017
Accepted: 4 May 2018
First Online: 11 May 2018
Ethics approval and consent to participate
: These data were approved by the KCDC Institutional Review Board, and all participants provided written informed consent.
: All authors, JHK, KJL, HRY, JYC, JSM, YK and JSK, declare that they have no competing interests.
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