Post #1285: COVID-19 update to 10/12/2021: No change, but I got my booster shot today anyway.

Posted on October 13, 2021


The Delta wave continues to recede.  The U.S. stands at 28 new COVID-19 cases per 100K population per day.  That’s down 46% from the peak of the Delta wave, and down 11% over the past week.

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 10/13/2021, from”  The NY Times U.S. tracking page may be found at

No sign of a winter wave yet. 

I wonder if this year’s weather is a factor.  Recall that I believe that indoor relative humidity is the main driver behind the winter COVID season (Post #894).  That will go below the optimum 40% level once the weather turns colder and dryer for the fall.

Below are state-level minimum temperature (left) and precipitation (right) maps for September 2020 (top) and September 2021 (bottom).

Source:  National Oceanographic and Atmospheric Administration

For temperature (left map), red is hot, blue is cool.  Moving from top (2020) to bottom (2021), in the Midwest, this September was definitely warmer than last September.

For precipitation (right map), blue-green is wet, brown is dry.  Again moving from top (2020) to bottom (2021), it looks like September 2021 was somewhat wetter than September 2020.  Certainly, the Dakotas — leaders in last year’s winter wave — are wetter this year than last year.

In short, in the Midwest, this September was warmer and wetter than last September.

I don’t know if that’s quantitatively large enough to explain a delayed onset of a winter COVID-19 wave.   Otherwise, if this year’s winter wave is going to be a straight-up repeat of last year’s, then we ought to start seeing the highlighted lines in the first chart begin to turn upward.  And there’s no sign of that yet.

Safeway redux

Here’s how my day started.  My wife turned to me and said, “We’re like a couple of geezers here for the early bird special.”

This, in response to going to our local Safeway for COVID-19 boosters and finding ourselves to be the only customers there.

Two weeks ago, we went to Safeway for flu shots in the middle of the day (Post #1273).  At that time, the place was jammed, and the pharmacist was working flat-out to provide immunizations.

This time, we figured we’d get there right at the opening, to avoid the crowds.  Early birds, in other words.  We showed up around 9 AM, and we were the only ones in line.

I asked the pharmacist whether things had settled down, and once again, she just laughed.  Nope.  She’s still doing vaccinations pretty much full-time.  We just happened to hit the one slack period during her work day.

The decision to get a booster isn’t as critical as the decision to get vaccinated in the first place.  But when I looked over the evidence, it seemed like more than enough additional benefit to make it worthwhile.  So now we’re triple-vaccinated.  And we still wear masks in indoor public places.

That may seem a bit extreme to some.  And maybe it is.  But only if you’ve lost sight of the severity of the illness.  As of 10/10/2021, we’re still at the point where about 8% of all persons diagnosed with COVID-19 get hospitalized, and about 1.5% of persons diagnosed with COVID-19 die from it.

(That is based on seven-day moving averages as reported on the CDC COVID data tracker.  For 10/11/2021, CDC lists ~88,000 new cases, ~7,000 new hospitalizations, and ~1,350 deaths, for an 8% hospitalization case rate and a 1.5 percent mortality case rate).

Admittedly, almost all of that is now among the unvaccinated.

Source:  Calculated from Virginia Department of Health COVID-19 dashboard data.

And your absolute odds of getting it remain slim, unless you work in a high-exposure occupation.

But that’s still an impressively bad set of outcomes for a disease you can get just by breathing the air.  And so, for the time being, as long as risk reduction costs us nothing, we’ll continue to try to minimize our risks.