Visiting Column #44 -- My COVID-19 Figures or Yours

I got a tweeted reply today to something I had written, in regard to the status of breweries in North and South Carolina relative to Wuhan virus handling:

"If masks work, why are some businesses forced to stay closed? On the flip side, if masks don’t work, why are we all being forced to wear them?"

I have an answer for him, but it was going to take too long for a tweet and, anyway, the answer is fairly deep.

The first part of the answer is that, as I think the science is fairly clear on, masks are a pretty ineffective way to avoid getting the virus, but a fairly decent way to avoid spreading the virus.  Follow?  According to the figures, face masks are really for the infected person to avoid spreading it through coughing, sneezing or other means of expelling virus-laden droplets.

The second part is the harder part, since almost anything said or written dealing with Wuhan virus spreading is subject to political spin, and I'm more interested in factual stuff.  That's why I used the word "stuff", since it's real technical and I'm an MIT guy.

I might have the virus.

I don't know, because I have no symptoms and have not been tested, and I don't think I have it, but I have no idea.  You see, I have not been tested because I have no symptoms.

And that's the thing.  Neither have a lot of people; they don't have symptoms.  We don't find out if they do or do not have the virus, because they're not tested.

Do you get the missing part of all this?  Of all the people exposed to the virus and who would test positive for it, some percentage are symptomatic and the rest not.  Of all the positive-test people symptomatic, some percentage die and the rest recover.  Two different things. Pause on that for a second.

We do know that in this country, that second percentage is about four or five percent now, and maybe above 5% in some countries with not-great medical facilities.  So in the USA, about 5% of people with the virus and who show symptoms die, very skewed toward the very elderly.  That's about what it is with the flu, although the flu doesn't skew as badly toward the elderly.  As one example, in Minnesota as of this week, more people in Minnesota over 100 years old have died of COVID-19 than Minnesotans under 50.

But I digress.

While we know the second figure, the mortality rate for those people with symptoms who test positive, we do not know the other figure at all yet -- that is, we don't know what percentage of people exposed to COVID-19 show any symptoms!

We don't know that because we have not taken a population -- a city, a state -- and tested everyone to see what the infection rate is.  There are not enough tests to do that, but it sure would be a good thing to know.  It is possible, friends, that 50% of the USA would test positive, and I'm not kidding.

While I realize that not having that figure makes this article a bit incomplete, the point of the piece is just that -- something we do not know, that would affect policy greatly if we did.  For example, let's say that only 50% of infected people show symptoms (I'm expecting it is even less, but let's be conservative).  That means that the 1.8 million symptomatic cases in the USA as of today is actually from almost four million infections, and the death rate is only 2.5%, not 5%.

But it could be much more extreme than that; we know that many names listed as COVID-19 deaths are not.  It is also certainly possible that only 20% of people exposed (and who would thus test positive) become symptomatic.  That means that the death rate for all positive tests would be 1%, and that is less than the flu, for which we don't shut the economy down.

So masks ...

The question from the fellow on Twitter was why, if masks don't work, we have to wear them and why, if they do, we need to shut down businesses.  Good question.  And after the missing data I point out above, you should see the answer.

We know that masks are for the spreader, not the "spreadee."  Am I a spreader?  Well, since I've not been tested, I don't know -- and that's why I should wear a mask, because I could already be infected, and need to protect others around me.  And it is why even people without symptoms should wear them for now, because you might be infected and don't know it.

And why are businesses shut down if they do work?  Now, I don't agree with doing this (I think business should open right now and practice safety, but still be open), but it's because masks aren't 100%; they're only about 70% effective.  They would reduce the transmission rate but not eliminate it. 

So in certain business situations, with big crowds, masks would help a lot, but not be as effective as one might want.  And given the missing data on asymptomatic infections, it's possible that masks are even less effective than that 70%.

I'll be candid -- I personally think the reason "businesses are shut down" still, even after the curve is flattened, because the more leftist governors have seized on an opportunity to control their citizens, and free economies are not conducive to tight government control.  It is a rare opportunity for the left not to miss a crisis opportunity to seize power, and they don't then relinquish it readily.

But just remember -- until we know the symptomatic rate among the infected, there is some serious policy-making going on in a vacuum.

Copyright 2020 by Robert Sutton
Like what you read here?  There are over 1,000 posts from Bob at www.uberthoughtsUSA.com, and after four years of writing a new one daily, he still posts thoughts once in a while as "visiting columns", no longer the "prolific essayist" he was through 2018, but still around.  Appearance, advertising, sponsorship and interview inquiries cheerfully welcomed at bsutton@alum.mit.edu or on Twitter at @rmosutton