During COVID-19, governments and the public are fighting not only a pandemic but also a co-evolving infodemic—the rapid and far-reaching spread of information of questionable quality. We analysed more than 100 million Twitter messages posted worldwide during the early stages of epidemic spread across countries (from 22 January to 10 March 2020) and classified the reliability of the news being circulated. We developed an Infodemic Risk Index to capture the magnitude of exposure to unreliable news across countries. We found that measurable waves of potentially unreliable information preceded the rise of COVID-19 infections, exposing entire countries to falsehoods that pose a serious threat to public health. As infections started to rise, reliable information quickly became more dominant, and Twitter content shifted towards more credible informational sources. Infodemic early-warning signals provide important cues for misinformation mitigation by means of adequate communication strategies.

在COVID-19期间，政府和公众不仅在与流行病作斗争，而且还在与共同发展的信息病作斗争-信息质量令人怀疑的信息的迅速而深远的传播。我们分析了流行病传播到各个国家（从2020年1月22日到2020年3月10日）在全球范围内发布的超过1亿条Twitter消息，并对正在传播的新闻的可靠性进行了分类。我们开发了一个Infodemic风险指数，以捕获各个国家/地区不可靠新闻的暴露程度。我们发现，在COVID-19感染上升之前，可测量的潜在不可靠信息浪潮使整个国家暴露于对公共卫生构成严重威胁的虚假信息。随着感染开始增加，可靠的信息很快变得越来越重要，Twitter的内容转向了更可靠的信息来源。信息量大的预警信号可通过适当的沟通策略为缓解错误信息提供重要线索。