How Would It Spread with No Intervention?

The following charts are based on the data found at https://www.worldometers.info/coronavirus/country/us/ and represent a trend if there were no intervention. That is an important caveat, as the pictures might be otherwise alarming.

First: Fit the raw data to a curve. This is not necessarily the best fit. I fit a curve to each two points from first major spike (02 MAR 2020) to the next to most-recent data point. I compared each such exponential curve to all others to find the best (least-squares) fit. The resulting curve looks to be a pretty good fit.

A least-squares fit of the data (blue dots) to an exponential curve (red line) as of 18 MAR 2020

Second: What do we do with models? We make predictions. Again, this is assuming that NO INTERVENTIONS have taken place. Certainly they have. While nearly nothing has been done by the hamstrung Federal agencies, states, cities, and private companies have been forced to take the reins. Hopefully we will start to see results soon. But for the time being, we probably won’t see too much change in the next week. So this might be an accurate look.

Extrapolating out based on the previously described exponential curve

Third: Hopefully, the non-Federal agencies’ efforts will have begun to pay off. If not, we could begin to expect something like this in two weeks.

How the exponential growth would look in two weeks, absent any effective mitigation

Fourth: I want to make it absolutely clear that I do not expect this to happen. The Federal organizations will have begun to overcome the sabotage of their capabilities, and state and local organizations will likely have become more efficient. Additionally, at this point, the ocean may no longer be considered infinite. That is to say, as a significant fraction of the population is exposed, the curve must begin to level off. A large fraction will have recovered and will no longer be contagious. A smaller number will have died and will also no longer be contagious. And multiple exposures to an individual from different sources will still only net a single potential infection in that person. That said, this is the point when out health care system would become extremely taxed.

Hopefully, the number of cases will have begun to level off a couple of weeks before we reach this point.

Perhaps tomorrow, I will look at the relative success of South Korea to see the upper end of our optimism.