Post #931: Simplifying the picture of COVID-19 in the US

Posted on December 29, 2020

Above:  Trend in new COVID-19 cases/ 100,000/day, my calculation from NY Times Github repository data reported through 12/29/2020.

  • Black = already peaked, no longer a concern for “out-of-control COVID”.
  • Green = stable rate, possible downward trend.
  • Orange = stable rate, possible upward trend.
  • Gray = California.

I’m sure you’ve been reading newspaper articles about the crisis in hospitals in Southern California.  I’m just here to point out what you’re not seeing:  Articles like that about anywhere else in the U.S.A.

And that’s because the state of the U.S. is pretty much as pictured above.  There’s California.  And then there’s the rest of the U.S.

The U.S. third wave of COVID is clearly ebbing in the entire mid-section of the country, after many of those states hit very high rates of new cases/ 100,000/ day.  I’ve pictured that in black, because unless things change, we don’t have to worry about those states any more.  They’ve seen the worst of it, and they are now seeing the light at the end of the tunnel.

Elsewhere, other than California, things are stable.  We have a mix of states where the rates appear to be drifting up a bit, and states where the rates appear to be drifting down a bit.

And then there’s California.  Really, Southern California.  Where the new-case rates are high, and it’s not yet clear what direction they are headed.  I attribute that to a combination of an extremely dry fall (See Post #894 on why that matters), and a high proportion of the population being Latino (see Post #719).  But I seem to be pretty much alone in that.

Above:  New cases / 100,000/ day, calculated from NY Times Github data repository, data reported through 12/28/2020.  NE =  Northeast (New England and Mid-Atlantic), SA = South Atlantic, MW = Midwest, SC = South Central, MT = Mountain, P = Pacific.

And so, if you graph the data by six broad regions of the country, you see that, for the time being at least, all those lines end on a down-slope. 

For some (Midwest and Mountain, yellow and blue), new-case rates have been falling long enough, and have fallen far enough, that we can safely declare them to be past their peak.  For others, such as the Pacific region (green line) and the South Atlantic (orange line), it’s too soon to tell whether that’s a peak or not.

But the point is, what is notably lacking, as of today, is any region where the trend lines are pointing up.  And there’s only one region with crazily high new case counts.  That’s the Pacific region.  And that’s due to California.

And so in some sense, there’s California.  And there’s the rest of the U.S.

Detail follows.


The state of the States as of 12/28/2020, in graphs and tables.

Midwest and Mountain states:  Already peaked.

Let me start here, because we can just cross these off our list.  Given the uniformity, and the estimated high fraction of the population that has already been infected, it would be a huge surprise if there were some sort of turnaround there.  There probably simply are not enough un-infected people left in that region to sustain a significant rebound in infection rates.  (That is, they’re close to or above herd immunity.)

Note:  The CDC “eight times” estimate above can be seen (in cartoon version) here, on this CDC webpage.  So, to be clear, I’m not the one saying that actual cases are about eight times the known, diagnosed COVID-19 cases.  That’s the CDC saying that.  (And, as it turns out, China recently estimated that the ratio was ten times, for Wuhan, which makes the CDC eight-times estimate seem fairly reasonable.)   It’s certainly imprecise to apply that single national estimate to all states, as I have done above.  But at this point, it’s the best (and only) estimate we have.

East Coast and the South:   Muddling through.

With the exception of Tennessee and Rhode Island, no state here has seen a high (> 100) rate of new cases / 100,000/day in the third wave.  And no state is showing any particularly strong trend.  And a lot of these states still have a high proportion of the population plausibly uninfected.

Right now, the preponderance of trend lines points down.  But there’s no way to say whether or not that will continue.

Pacific states:  It’s all about California.

On a population basis, the Pacific states are driven by California.  Has California peaked, or not?  As of today, California doesn’t quite meet the criteria I used to call the peak in Tennessee, because it hasn’t fallen a full 20 case/ 100,000/day, from that peak rate, yet.  But it’s looking peak-ish.

I don’t normally get down to the county level, but I am curious about one statistic.  At this point, what fraction of Los Angeles residents have been diagnosed with COVID-19?  As of today, they have 733,325 diagnosed cases (per this reference), out of an estimated population of 10 million.  So, 7.3% diagnosed, which would be an estimated 58% of the population already having been infected, using the CDC “eight times” finding (small print above).

If you look at the table above, that’s approaching the level that strongly suggests that they ought to be seeing a peak in their infection rate.  I’m betting that what appears to be a peak, above, for California, actually turns out to be the peak.