Table 2.

Digital contact tracing solutions deployed in Japan and Germany in response to the COVID-19 pandemic.

Characteristic	COCOAa (Japan)	HER-SYSb and MyHER-SYS (Japan)	Corona-Warn-App (Germany)	SORMASc (Germany)
Classification	Proximity tracing	Outbreak management and symptom tracking	Proximity tracing	Outbreak management
Primary end users	Public	Health authorities and public	Public	Health Authorities
1. Source code published on a publicly accessible repository?	Yes (GitHub; English, Japanese) [27]	No	Yes (GitHub; English, German) [28]	Yes (GitHub; English) [29]
2. Source code accessible for public input, feedback, or interaction?	Yes (Process described in project ReadMe file hosted on GitHub) [30]	No	Yes (Process described in project ReadMe files [multiple] in separate folders hosted on GitHub) [28]	Yes (Process described in project ReadMe file hosted on GitHub) [31]
3. High level of independent or public source code customization possible as dictated by appropriate OSS license?	Yes (Process described in developer ReadMe file hosted on GitHub) [30]	No	Yes (Process described in developer ReadMe files [multiple] in separate folders hosted on GitHub) [28]	Yes | Process described in project ReadMe file hosted on GitHub [31]
License	Free to customize (Mozilla Public License version 2.0)	—d	Free to customize (Apache License version 2.0)	Free to customize (GNU GPL v.3)

^aCOCOA: COVID-19 Contact-Confirming Application.

^bHER-SYS: Health Center Real-time Information-sharing System on COVID-19.

^cSORMAS: Surveillance Outbreak Response Management and Analysis System.

^dNot available.