Post 922: Calling it for no Thanksgiving surge; COVID-19 stable in 47 states.

Posted on December 18, 2020

Today I’m just presenting the graphs of seven-day moving averages of new COVID-19 cases/ 100,000/day, for state grouped by six regions.  They’re at the end of the posting.  I only want to make two points.

No post-Thanksgiving surge

The data now run through 12/17/2020, three full weeks after Thanksgiving.  At this point, with some small risk of being wrong, I’m going to call it.  Just use your eyes.  There was no post-Thanksgiving surge in cases.   If you’ve been reading along, that’s no surprise.  And that matches the lack of a surge in Canada, following Canadian Thanksgiving (Post #).

Wouldn’t we all like to know why, given that we’re about to re-do that, in spades, more-or-less starting this week.  Wouldn’t we like our public health authorities at least to discuss it?  Not gonna happen.

I’ll just hazard my guess here:  I think people who traveled for Thanksgiving were exceptionally cautious, on average.  I think all that messaging around Thanksgiving got through to people.  I have no way to prove that.  But of the possible explanations, that’s the one I think is most plausible.  For sure, sitting next to somebody with COVID, on public transport, has a non-negligible risk of transmission (reference).  (It’s not clear whether passengers were wearing masks in that study.)  Why those transmissions didn’t occur, here, I’d have to chalk up to testing, mask-wearing, and similar preventive behavior.

While the news media were full of warnings prior to Thanksgiving, I have a hard time recalling even one news story focused on the parallel dangers for the coming week.  I guess you can say “skip Thanksgiving this year”, but nobody can plausibly say the same for various year-end holidays.   And so for the coming holiday travel there has been no barrage of public-health messages.  Let’s hope that people act cautiously, regardless.

A surge of cases in just two states:  CA and TN

While new-infection rates are high in many areas, they aren’t rising.  If you look at the lines on the graphs at the end of this posting, most end with level-to-downsloping segments.  The two gross exceptions are CA and TN, with a third possible exception in AZ.  Those are the three with high and rising COVID-19 new-case counts.

Source:  NY Times.

TN is truly an exceptional outlier, because nothing about the geography, population, or weather suggests that they ought to go the way of the Midwest.  As you can see from the graph, their troubles have been building for months (so this isn’t some unique post-Thanksgiving surge.)  And as you can see from the map, their troubles are spread uniformly across the state.

The only thing they have in common with the hardest-hit Midwest states is that they have a Republican governor and, accordingly, minimal response to COVID-19.  (Apologies as always to cousin Larry).  For example, they have no mask mandate, and any business restrictions appear to be strictly local in nature.

To me, similar to much of the Midwest, they now look like a state that did fine until the weather changed, and their risk-taking is now catching up to them.  At the peak, the ND map had that same look — COVID was everywhere.  And so, what worked for them in August isn’t working for them in December, and they’re not nimble enough to figure that out and change behavior accordingly.  My guess, at this point, is that they are going to follow in the footsteps of ND.

But they haven’t quite run out of ICU beds yet.  As of today there are still 161 ICU beds open (reference).   If they stick by the playbook, the state government will take no action until that approaches zero.  Probably have another week or two to wait for that.

CA, by contrast, has both weather and population working against them.  Weather, in the form of an exceptionally dry November in Southern California.  (See Post #894 for the key role that humidity plays.)  If you un-focus your eyes a bit, you’ll see a fairly strong north-south differential across the state.

And population, in the form of a high percentage of individuals of Hispanic origin.  COVID-19 has taken an exceptionally high toll on the Latino population pretty much everywhere, including here in Virginia (Post #719).  I don’t think anyone is quite sure why.  That has been casually attributed to occupational mix, with a purported heavy presence among at-risk health care workers.  But it’s not clear that’s an adequate explanation.  In any case, unlike TN, CA has been doing much to try to prevent spread of disease.  They’re just not succeeding, particularly in the dryer areas.