The human and social toll of the coronavirus disease 2019 (COVID-19) pandemic has already spurred several major public health "lessons learned," and the theme of effective and responsible scientific communication is among them. We propose that Twitter has played a fundamental-but often precarious-role in permitting real-time global communication between scientists during the COVID-19 epidemic, on a scale not seen before. Here, we discuss 3 key facets to Twitter-enabled scientific exchange during public health emergencies, including some major drawbacks. This discussion also serves as a succinct primer on some of the pivotal epidemiological analyses (and their communication) during the early phases of the COVID-19 outbreak, as seen through the lens of a Twitter feed.