Background: The World Health Organization declared the novel coronavirus outbreak (COVID-19) to be a pandemic on March 11, 2020. Large-scale monitoring for capturing the current epidemiological situation of COVID-19 in Japan would improve preparation for and prevention of a massive outbreak.

Methods: A chatbot-based healthcare system named COOPERA (COvid-19: Operation for Personalized Empowerment to Render smart prevention And care seeking) was developed using the LINE app to evaluate the current Japanese epidemiological situation. LINE users could participate in the system either though a QR code page in the prefectures’ websites or a banner at the top of the LINE app screen. COOPERA asked participants questions regarding personal information, preventive actions, and non-specific symptoms related to COVID-19 and their duration. We calculated daily cross correlation functions between the reported number of infected cases confirmed using polymerase chain reaction and the symptom-positive group captured by COOPERA.

Results: We analyzed 206,218 participants from three prefectures reported between March 5 and 30, 2020. The mean age of participants was 44.2 (standard deviation, 13.2) years. No symptoms were reported by 96.93% of participants, but there was a significantly positive correlation between the reported number of COVID-19 cases and self-reported fevers, suggesting that massive monitoring of fever might help to estimate the scale of the COVID-19 epidemic in real time.

Conclusions: COOPERA is the first real-time system being used to monitor trends in COVID-19 in Japan and provides useful insights to assist political decisions to tackle the epidemic.

背景：世界卫生组织于2020年3月11日宣布新型冠状病毒爆发（COVID-19）为大流行病。大规模监测以捕获日本COVID-19的当前流行病学状况将改善对流感病毒的准备和预防。大规模爆发。

方法：使用LINE应用程序开发了一个基于聊天机器人的医疗系统，名为COOPERA（COvid-19：个性化赋权操作，以提供智能预防和护理服务），以评估当前的日本流行病情况。LINE用户可以通过县网站上的QR码页面或LINE应用程序屏幕顶部的横幅来加入系统。COOPERA向参与者询问有关与COVID-19及其持续时间有关的个人信息，预防措施和非特定症状的问题。我们计算了报告的使用聚合酶链反应确诊的感染病例数与COOPERA捕获的症状阳性组之间的每日互相关函数。

结果：我们分析了2020年3月5日至30日之间三个省的206,218名参与者。参与者的平均年龄为44.2岁（标准差为13.2年）。96.93％的参与者未报告任何症状，但所报告的COVID-19病例数与自我报告的发烧之间呈显着正相关，这表明对发烧的大量监测可能有助于估计COVID-19流行病的规模实时。

结论： COOPERA是日本第一个用于监视COVID-19趋势的实时系统，并提供了有用的见解，以协助应对该流行病的政治决策。