COVID-19 July 08, 2020

I was too busy to post yesterday and still too busy today to provide any narrative.  But, here's the data.

COVID-19 July 06, 2020

Way back when, when all this was starting, I cautioned about applying national statistics too broadly.  At the time, New York was surging and the bulk of national statistics were coming from the state.  Those numbers almost swamped out data and trends from other places.  Many states also had growing infections and deaths, but New York was a standout.  If you applied the average national numbers you would get the wrong impression of what was actually happening nationally and you'd get the wrong impression of what was actually going on in New York. 

There's a name for the phenomena that I've described above: Simpson's Paradox.  Wikipedia has a nice summary: https://en.wikipedia.org/wiki/Simpson%27s_paradox .    The bottom line is, be very careful how you interpret statistics.  The statistical number crunching can be accurate, but the interpretation can be deceiving.  You really do need to understand the nature of the problem and some amount of detail about the origin of the numbers.  This goes for most everything: COVID trends, police and race, bias in proposal selection, and bias in college admissions. 

I've previously given some possible explanations for the rapid rise in infections and the lack of such a rise in deaths.  Simpon's paradox is one more possible explanation to add to that list.  Deaths may be decreasing or steady on average across the country, but that is not necessarily the case in Texas, Florida and Califonia the bulk of new cases are coming from.  To my eye, there is at least some indication that the death rate in the first two states has been inching up over the last couple of weeks.  It's not dramatic, and I haven't formally run the numbers, but the trend does appear to be there.  You can look at various other websites that track the data.  Texas deaths look to be going up since mid-June. Same in Florida.  California, however, has been pretty flat. 

And now, I bring you the official numbers from yesterday.  It was a typical down day with the oscillation effect amplified somewhat by the holiday and the weekend.  Let's see the numbers later this week.

COVID-19 July 05, 2020

Today would normally be a down day with the numbers, but given the holiday they look especially wonky.  For example, my state of Colorado reported only 7 new infections where the daily number has been consistently in the hundreds.  I'm guessing people were on holiday and there was no one to answer the mail or to report the numbers.  The cases and deaths are still happening, so we can probably anticipate a bigger bounce later in the week.  Some states, like Florida, reported a record daily number even with the holiday.  That can't be good. 

As reported yesterday, the trends have stabilized.  We are in exponential growth with a doubling time of new cases of about 15 days.  Daily deaths are nearly constant now.  They occasionally go up a bit and down a bit, but on average it's close to a constant rate.

COVID-19 July 04, 2020

Data continues to show that are blowing past what we saw in the first wave.  And, yes, I do believe there was a first wave, contrary to what many are saying.  We are not still in the first wave.  There was a pronounced initial rise, a clear peak, and a gradual but persistent decrease.  That's a wave by most definitions.  It could be said that the first wave brought in the tide that didn't completely recede, but it is a wave nonetheless.  We've now seen a dramatic reversal of trends as the next wave comes in on top of the higher tide.  This is the second wave, and in terms of sheer numbers it is bigger.  Note that the data plotted in green on the new case graph shows the data since June 9 shifted and displayed over the first wave data.  The rate of rise is similar, but we've blown past the peak of the first wave.

Will the second wave be worse than the first?  Hard to say, but it seems likely.  Deaths still have not taken a rapid upward trajectory, but with hospitals and ICUs starting to reach capacity in the hardest hit areas it's hard to see how deaths will not start to increase.  The downward trend has certainly slowed and the 7-day trend has actually shown a slow increase rather than decrease.  See my previous posts over the last few days for additional thoughts about why this is.

Data is plotted below, as usual.  The best fit 7-day line shows just under 50,000 new cases/day.  The exponential fit to the new cases shows a doubling rate of close to 15 days.  This number has, fortunately, more or less stabilized and is no longer rapidly shrinking.  If and when we start to flatten the curve of this wave, we will need to see the doubling rate rise consistently. 

Have a good 4th!  My dog, Layla, thanks you for going easy on the boom booms.

EDIT: I reposted the daily new cases graph b/c I somehow managed to mess up some of the date labels in the original post. Data has not changed.

COVID-19 July 03, 2020

Independence Day or Groundhog Day? You decide!  I won't belabor the numbers from yesterday.  Unless you've been living in a cave, you all know the situation.

Today, I took data for the number of new cases since June 9 (shown in red on the daily new cases graph), shifted the values, and overlayed that data on the historical data from the beginning of the pandemic.  That shifted data is labeled as "June 9 shifted" in the graph and is shown in green. Surprise!!! The rise in cases since June 9 looks almost exactly like the rise at the start of the pandemic!

We really are right back where we started.  Or are we?  At the end of March, lockdowns were already well underway and the result was that the curve did start to flatten by early April.  For example, our office encouraged remote working on March 12 and less than a week later we shut the office down except for essential personnel.  That's not what's going on now.  Where we are now is roughly equivalent to where we were at the end of March, but rather than being in a process of increasing restrictions we are in an environment of loosening restrictions.  At least some of the state Governors got the memo and are requiring masks.  It seems unlikely that the curve is going to flatten anytime soon under these conditions.  I think we are in a far worse place:  Groundhog day on, I don't know, PCP?

I've had a few questions about why deaths are not rising in concert with the new cases.  I've addressed that here and there, but I'll drop my hypotheses in the form of an abbreviated list for clarity:

1)  Demographic shift in infections.  The morbidity probabilities are heavily skewed to the elderly. The initial pandemic hit the elderly populations hard, especially in nursing homes.  The current rise in infections is heavily skewed to the younger population who are less likely to die. (Note: that doesn't mean the young are immune.  Plenty of healthy, young people with no obvious risk factors are finding themselves dead or injured for life).  I expect this to start to change as young people bring their new viral friends home.

2)  Better treatments.  Through trial and error, treatments have improved at least a little.  This can't account for all the difference, but I'm going to guess it has some impact.

3)  Increased testing.  Part of the rise in infection rates is due to increased testing. If we had the same pathetic level of testing now that we had early on, the rate of increase would likely be different.  (Note: this has implications for whether we really are in a Groundhog Day scenario).  The increased testing cannot however explain all of the increase in new cases.  Not by a long shot.

4)  Virus evolution.  There is evidence that the virus has mutated, particularly in the spike protein that binds to the ACE-2 receptor of the human cell.  There is no evidence that this makes it any more or less lethal, but it does, apparently, make it more infectious.  There have been other mutations, but based on my limited understanding (and I want to emphasize LIMITED.  I AM NOT AN EXPERT and will defer to those that are if I say something that is inaccurate.  Experts: let me know!), there is no strong evidence that the virulence has been altered.

5) Other reasons.  There are almost certainly other influences that I've left off.

COVID-19 July 02, 2020

I barely have time to post, but I wanted to distribute today's graphs.  Text the word "UP" to 321321 for more information.

COVID-19 July 01, 2020

And July starts off with a BANG!  Things are back on the rise as they almost always do on a Tuesday.  Numbers should continue to go up the rest of the workweek.  It's really just a matter of how much.  By the end of the week, we'll have over three weeks of data on the recent rise in infections.  That's enough data that the curve fits should start to become more meaningful.  Right now, the exponential fit is still showing infection rates doubling about every 15 days.  The average is now over 41,000 per day.  So, if the exponential rate doesn't change, we'll be at over 80,000 per day by mid-July.  

The death rate still hasn't gone exponential, but it isn't dropping either.  With each day we diverge more and more from what could have and should have been.  Oh well.  Water on the bridge.