Communicating public health messages during a pandemic necessitates the ability to reach everyone quickly. This role has traditionally belonged to government leaders, but with so much misinformation easily published, sharing accurate information can be challenging.

During the current COVID-19 crisis, we’ve seen the phrase “Flatten the Curve” clearly and concisely provide a call to action. While the public health community has been familiar with versions of the image and the expression for years, until just a few weeks ago most of the public had never heard it said before.

How had did this phrase go viral and become part of our common lexicon in such a short time?

To understand how this message spread and how as health communicators we can try to replicate this success, we looked at the sources that drove the message spread with GRETEL®, JPA’s analytics tool that tracks the influence of health content.

With GRETEL, we look at specific audiences using real-time data to understand the information sources that each audience engages with online. In some cases, such as our research with the NIH that was recently published, the GRETEL platform is used to identify gaps in health education sources for audiences who need reliable information. In other cases, we use this data to identify the best places to advertise or place earned media stories to inspire dialogue on a health topic.

The GRETEL platform showed that the phrase “Flatten the Curve” was first used on February 27 by a visible source, a blog by Scientific American. While the publication often reaches scientific audiences, this post did not resonate with any of the audiences we track, but it did spark interest among reporters.

Just one day later, an article was published on February 28 in the Economist, which was the first piece to use the chart that is now ubiquitous. This publication has a large readership and is often cited in social media, but not often by the public health or medical community.

That same day, the #FlattenTheCurve hashtag was used on Twitter. Still, it was only shared by a single person.

While there were a few posts over the next few days, two events happened on March 6 that started the acceleration of the now-popular phrase:

1. A story appeared on Vox that helped drive the conversation into social media.
2. Carl T. Bergstrom, a biology professor at the University of Washington, posted a tweet from the Economist, and focused on the power of the #FlattenTheCruve image (his Twitter thread includes details on the authors of each of the versions of the chart). Our data show that Bergstrom is highly influential in the online scientific research community.

At this point, the clinicians started sharing these posts on #MedTwitter, the rapidly growing part of the channel that health professionals use globally to share information and interact with one another and patient advocates.

Physician and author Eric Topol, the most influential healthcare professional on social media according to our data, highlighted the terms and chart in a post on March 7. Dr. Topol also retweeted the Bergstrom thread along with several other versions of the chart.

Over the next few days, the hashtag #FlattenTheCurve grew exponentially within medical audiences. The conversation started spreading to wider public audiences as the Economist piece and others began to resonate throughout the online conversation.

On March 11, the New York Times covered the story and included the chart. Within a single day, the chart and the expression began echoing within news media and social media platforms across the world.

That was the tipping point. The public learned the term and began searching Google for a definition. Over the next few days, social media discussions on #FlattenTheCurve began to plateau as the phrase entered the general lexicon.

The rapid uptake of #FlattenTheCurve – from #MedTwitter to the news media to the world –demonstrates the power of a few individuals to engage thousands or even millions globally. While, as of March 23, we haven’t yet seen the number of new COVID-19 cases flatten within the U.S., the speed and reach of this important public health message gives us hope in our ability to act together and address this crisis.