Received: 3 June 2020
Accepted: 8 June 2020
First Online: 3 July 2020
Ethics approval and consent to participate
: This case series was approved by the institutional review board at the University of Tokyo (#3820). The institutional treatment board at The University of Tokyo Hospital approved the treatment protocol of antiviral agents of favipiravir and nafamostat mesylate (#2020001CL). Informed consent for treatment was obtained from each patient or legal representative.
: Not applicable
: One author (JI) has submitted a provisional application for a patent related to this work to USPTO under the application no. 62988962. The other authors declare that they have no conflicts of interest with the contents of this article.