By what mechanisms would you determine your answer to this question? What comparisons should we be making? Should we compare against other linear growth examples or focus on exponential growth examples? Should we research previous epidemics that also had exponential growth characteristics such as the 1918 Spanish Flu?

It infected 500 million people around the world, including people on remote Pacific islands and in the Arctic. The death toll is estimated to have been 50 million, and possibly as high as 100 million (three to five percent of Earth's population at the time), making it one of the deadliest epidemics in human history.

Should we consider SARS that was also growing exponentially but, thankfully, happened to be a rather weak virus and didn't survive long? What about how this virus spreads with no symptoms and how does that impact our models for contagion? How does our hyper-connected society with millions of people on flights every day change the distribution models?

Some might say we aren't reacting enough. Every day we get more information to tell us if our world is about to change forever or if this will blow over as a "wow, that was really close" event.