Post #1203: COVID-19 trend to 8/4/2021. The “don’t give a damn about Delta” wave.

Posted on August 5, 2021

The U.S. is now just shy of 30 new COVID-19 cases per 100K population per day, on average.  The good news is that the growth rate for new cases per day seems to be slowing somewhat. 

Data source for this and other graphs of new case counts:  Calculated from The New York Times. (2021). Coronavirus (Covid-19) Data in the United States. Retrieved 8/5/2021, from”  The NY Times U.S. tracking page may be found at

I tend to lose track of that circled figure from day to day, so let me plot it so that you can see that the percentage growth rate in new cases has been declining steadily.  Here’s the trailing seven-day percent increase in cases, for the past two weeks.

Below, it looks like we’re making the transition from geometric growth (constant percentage growth in new cases per day) to arithmetic growth (constant increase in number of new cases per day).  The blue line is the same as the line shown above.  That’s the percent change.  The orange line is the change in the count of cases.  If you look to the right, these days, the count of new cases / 100K / day seems to go up by about 9 cases per week.  Today it’s about 30 / 100K / day,  a week ago it was about 21 / 100k / day.

Here’s the current wave, in perspective.  It’s now clearly the second-worst on record.

And if you just continue the line, by eye, you realize that if growth doesn’t slow soon, this will easily top the U.S. third (winter) wave in two or three weeks.  Which I can formalize by projecting at the current 43%/week growth rate.

But note that I’ve been saying “two to three weeks from now” for quite some time.  That’s a consequence of the declining rate of growth.  Here’s the same chart from a little over one week ago, showing the projection at the then-higher growth rate.


The slowdown in growth is welcome.  If it’s true that we’re transitioning out of geometric (constant-percent-increase) growth in new cases, that leads to a vastly lower predicted peak rate, and gives more time for U.S. population behavior to change before we actually exceed the winter peak.

The only fly in the ointment is that there’s no particular reason for the rate of growth to be slowing. 

You’re probably seeing some popular press coverage of an increase in vaccinations.  Putting aside the fact that today’s initial vaccinations will affect the observed infection rate about eight weeks from now, the “surge” in vaccinations is anything but:

Source:  CDC COVID data tracker.

Similarly, the level of COVID-19 hygiene being practiced is almost unchanged.   Here’s mask use through 8/3/2021, compared to new cases per day over the same period.  (I further note that there has been no decline in (e.g.) bar visits or restaurant visits (not shown).

Source:  Mask data from Carnegie-Mellon COVID Delphi project.  Case count data calculated from:  The New York Times. (2021), reference given above.

But the above charts are national data.  In the states that are hitting all-time records for new cases, surely the behavior of the residents will have changed much more than this?

Dream on.  Below are the two graphs as above, but for Florida:


Source:  CDC COVID data tracker.

Source:  Mask data from Carnegie-Mellon COVID Delphi project.  Case count data calculated from:  The New York Times. (2021), reference given above.

This is an expected result, I think.  This wave is driven by that segment of the population that, as a matter of politics, creed, or superstition, is bound and determined to do nothing about COVID-19.  We’re down to the 30% of the adult population that really and truly doesn’t give a damn about trying to reduce the number of infections in this Delta wave.

Well, que sera sera.

Hospitalizations rise more-or-less coincident with new cases.  And the interesting thing is that while hospitalizations are up, they are mostly up without the help of the elderly.  Like so, all from CDC:

Total new hospitalizations for COVID-19:

And then, by age, below, from children (yellow) to the oldest old (purple).   Note that these are all on different scales.  All they are showing you is that hospitalization rates for children and young adults are already at or near their wintertime peak.  By contrast, hospitalization rates for the elderly are a fraction of what they were in the wintertime peak.

Deaths only start rolling in after a couple of weeks of lag, as the median time from admission to death for COVID-19 decedents is around 12 days.

I’d say the odds-on bet is that the yellow line on this chart will rise commensurate with the rise in cases, but maybe this time will be different.  Almost all the COVID-19 deaths in the past have been in the elderly, and by and large, the high vaccination rate there is preventing hospitalizations, and so likely preventing deaths.

Here’s how Florida looks in this regard.  No worries there, obviously.  (Sarcasm).  They have weeks before they top the winter wave death rate, if they ever do.

I guess we’re going to find out.

Truly, I don’t understand it.  I can grasp wishful thinking as a substitute for public health policy during the first U.S. COVID-19 wave.  But on the fifth U.S. wave?  If I thought that the people involved actually cared about the outcomes, I’d say that’s nuts.


My best guess isn’t that they are incompetent.  My guess is, they just don’t give a damn.  For the people who are running this wave of COVID-19, it’s all just a great big joke.