Midweek Numbers and Analysis Update (6 May 2020)

As long time readers know, one of my main frustrations is with the “News Cycle” and how there is constant pressure to come up with “new” or “breaking” news. It’s not rational or conducive to mental health.  Most events move slowly.  For Hurricanes, things change on a daily to 12 hour time scale – certainly not hourly or less – until the storm is near landfall, and even then a three to six hour update is fine.  For a pandemic, things move far more slowly.  Even daily updates are problematic – it takes time for testing results to be available, and just the course of the disease is measured in weeks as it takes 5 to 10 days for someone who is exposed to become infected (and/or infectious), another 10 days or so of illness, if hospitalized that extends to 20 days.  Hospitalization and confirmed positive numbers are a look back in time about a week – deaths, about three weeks.  Throw in the noise and inept reporting in some states, and the moving target of what is a case vs a COVID death … well, you get the picture, and it’s pretty fuzzy.

But since it has been a few days, let’s see if anything has changed – certainly the mitigation measures have, as states like Georgia have begun to lift restrictions.  But, for the reasons noted above and in a previous post, we probably won’t see any serious impact on the numbers from these measures for about another week.  So looking now is a snapshot into what was happening when the measures were expiring.

First, lets look at testing.  Despite all the talk, only a very small fraction of the population has been “tested” (noting that being tested means different things – tests for active infection have very different meanings from tests for antibodies, and all of the tests have error rates and interpretation issues as this paper demonstrates.  So how many people have been tested?  Here are the results for five states …

… only NY is above 5% of the population.  If that were a random sample that would be great, but unfortunately it isn’t.  So what fraction of those tested are positive?

So in NY, over 30% of those tested are positive – for Michigan, 20%, for Georgia, about 15%.  Compare to Washington State, which is less than 8%.  This  indicates testing is still biased towards those who are seeking treatment, although the ratios are getting better, and testing is extending out into the general population.  What fraction of the population who have been tested positive are in the hospital?  Here’s that chart …

Wait a minute, some of you are probably thinking “what’s the deal, why aren’t you using the same states in each graph?”  Exactly!  Different states are reporting different things at different times and with different standards.  It’s unbelievably frustrating for anyone trying to understand what is going on with this pandemic.  You’d think a developed country would have national standards, but … this is the “state” of things.  Sigh.  So we can’t compare the same states with different metrics because some don’t report hospitalizations, some don’t report testing the same way, etc. But what we have is remarkably consistent for the places where we have data – about 20% of people who are testing positive ended up in the hospital at some point.  So how many of them didn’t make it?

 

So between 4 and 10 percent of people who have tested positive for the virus have died. Sorry to yell, but THIS DOES NOT MEAN THE CASE FATALITY RATE IS BETWEEN 4 AND 10 PERCENT!  Because, as noted above, the more people we test, the more show up positive.  We still do not have a good handle on how widespread this thing is.  Being selfish, what are the chances some random person will die from this?  That we can start to answer even if we don’t know how many people are infected. Let’s look at the whole population mortality rate here in ‘Murica! …

… and globally …

So in whole population terms, the worst hit countries like Spain, Italy, and the UK (after the big numbers correction 10 days ago) are converging to rates between 5.5 and 7 deaths per 10,000 people.  There seems to be a second tier converging to  around 4 per 10,000 (France at the high end, Sweden Netherlands), and a third tier to around 2.5 (Canada, Russia).  Some countries are on track to come in under two per 10k like Germany, Denmark and Norway.  And, of course, South Korea at well under one per 10k.  The US is a special case – it is so big and diverse, it’s not really fair to treat it as one thing.  Russia is almost in that category as well.   I’m ignoring Iran and China – their numbers are probably bogus.

So what does all this mean?  Bad influenza outbreaks are in the range of 2 to 3 deaths per 10,000, with bad recent outbreaks coming in at five per 10,000.  As previously discussed, SARS-COV-2 isn’t influenza – it moves much faster, stressing health care systems much more so than influenza.  For what it’s worth, I tend to agree with Professor Igor Gundarov, an epidemiologist at Moscow State University who suggests that relatively mild flu seasons, combined with a pneumonia vaccine that has reduced pneumonia deaths, means there were a lot of vulnerable, largely older people around who were a perfect ecological niche for this virus to exploit.  This seems especially true of the hardest hit areas.  In terms of societal impacts, I remain mostly concerned about the economy; even if there is no “second wave” of infection and death, we haven’t even seen the “first wave” of economic impacts …

In terms of personal behavior it’s more complicated. The best advice is still wash your hands, Sgt Apone rules (nobody touch nothin’), 2 meter (6ft) distance from people you don’t live with. Wearing masks in public places makes sense – for you a little, but for others a lot because it is increasingly likely lots of people are wandering around potentially spreading the virus.  We need a few more weeks of data to see if the pandemic is fading for real, or simply gone in to hiding.  Especially if you have vulnerable members of your family, stay paranoid about hygiene for now.  If you are back at work please take all precautions to protect yourself and your customers.  For those in retail, please watch this video and learn how to properly wear a mask!!!  Don’t leave your nose hanging out …

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