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Currently accepted at: JMIR mHealth and uHealth

Date Submitted: Jul 4, 2020
Open Peer Review Period: Jul 4, 2020 - Aug 24, 2020
Date Accepted: Sep 13, 2020
(closed for review but you can still tweet)

This paper has been accepted and is currently in production.

It will appear shortly on 10.2196/22098

The final accepted version (not copyedited yet) is in this tab.

Warning: This is an author submission that is not peer-reviewed or edited. Preprints - unless they show as "accepted" - should not be relied on to guide clinical practice or health-related behavior and should not be reported in news media as established information.

A COVID-19 Contact Tracing Self-Confirmation System for the General Population in Japan: Design and Implementation Evaluation

  • Ichiro Nakamoto; 
  • Yan Guo; 
  • Sheng Wang; 
  • MingHui Jin; 
  • Weiqing Zhuang; 
  • Ming Jang; 
  • Yi Huang; 



The global spread of coronavirus disease (COVID-19) has attracted extensive research concerns. It is an infectious disease resulting from a novel virus termed severe acute respiratory syndrome coronavirus 2 (SARS-COV-2). The joint collaboration of Ministry of Health, Labor and Welfare (MHLW) in Japan and new coronavirus infection control team has led to the formal issuance of a Bluetooth-based mobile app, which integrates privacy and security protection with methodical processing required for effective contact tracing of exposure to COVID-19.


Due to the demand for a contact tracing instrument that timely keeps track of exposure, teams of professionals and authority experts contributed to the design and implementation of a mobile app intended to provide the general population with updates of contacts at the individual level, including both the infected and the exposed, to manage the risk of close contacts in Japan. This study aims to evaluate the development and distribution of a Bluetooth-based mobile contact-confirming application (COCOA) for COVID-19 to integrate the efforts by healthcare practitioners, the infected and the exposed to contain the spread of COVID-19.


The Exposure Notification Framework (AGF) co-provided by Apple and Google is used in the provision of service. It distributes validated incremental information of COVID-19 that is closely related but might be unware to the individuals. Great emphasis is placed on the correct understanding of seven major steps (issue and confirm process code, report infection status, request information of the infected, calculate and compare exposure summary, provision of response guidance) needed in the process.


COCOA consists of three major components: the two mobile apps for the infected and exposed individuals respectively and the notification system that is used to manage and broadcast the information of infection and exposure. Users can self-confirm the risk of exposure to the COVID-19 by periodically fetching the outbreak data and choose provided available response to COVID-19.


COCOA is a mobile-based self-confirmation telehealth system developed to assist not only the government and healthcare providers, but also the infected and the exposed individuals to contain COVID-19 through rapid responses and effective non-contact cooperation. The design and the mechanism presents a desirable capacity to promote non-contact cooperation, forecast the potential risk of being infected and facilitate consequential measures to prevent further spread.


Please cite as:

Nakamoto I, Guo Y, Wang S, Jin M, Zhuang W, Jang M, Huang Y

A COVID-19 Contact Tracing Self-Confirmation System for the General Population in Japan: Design and Implementation Evaluation

JMIR Preprints. 04/07/2020:22098

DOI: 10.2196/preprints.22098


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