The Dream Virus

Inspired by a comment by El Borak on this post at Rotten Chestnuts.

For many decades now, it has been known that viruses always mutate, and tend to almost always mutate into less lethal forms. (1) Why viruses strongly tend to mutate into less virulent forms is basic applied Darwinism: a virus that kills its host is much less likely to spread than one that doesn’t. Dead bodies don’t get around much; people avoid dead bodies much more than they avoid live ones. Since any virus ‘wants’ to spread and replicate as much as possible, while its victims don’t ‘want’ to die, a milder, less fatal variation is much more likely to spread than a stronger, more fatal variety. (2)

Further, the fewer symptoms that announce a person is sick, the better, from the virus’s point of view. Having someone moaning in bed, or coughing up a lung, is not as likely to invite further interactions with potential future hosts, than a host that looks and acts more healthy.

The ideal virus would be infinitively infectious with no symptoms at all. And, indeed, at the moment it is likely you, me, anybody, has more virions in us than we have cells that are ‘ours’. They’re unimaginably small, for one thing, even compared to ‘our’ cells, and are simply everywhere. Some are symbiotic. But some are, evidently, just there. We humans have ‘coevolved’ with viruses for a couple billion years. They ‘know’ how to deal with us; we ‘know’ how to deal with them. In the normal course of things, viruses don’t ‘want’ to kill or harm us, and we are pretty much indifferent to their presence. Only once in a while does a mutation happen that increases the deadliness of a virus, and such mutations strongly tend to quickly fade out.

So we should have expected the COVID virus to a) mutate; and b) get more infectious and less and less harmful over time. And that’s exactly what the delta variant is: a more infectious but much less dangerous mutation.

Here’s what was shared by El Borak:

1) Do a duck duck go search for “technical briefing sars-cov-2 variants of concern”
2) The first item or two will lead you to a gov.uk link. Click it.
3) Download the latest “Technical briefing” This is official “raw” data about Covid and its variants by Health England. The latest is #19, published July 23.
4) Scroll down to Table 3, page 13 and look for the Delta line.

More than 229,000 cases (now more than half of all British cases since Day 1). 461 deaths. An overall Case Fatality Rate of .2% (2-in-1000. 1st line, p.15). That includes all the diabetic octogenarian grandmas who got missed in the first wave. For people under 50 the CFR is 0% (penultimate line, p 14).

Those are official numbers, so you can assume, probably, that they’ve made them look as scary as they could get away with.

But they are not scary. A virus that kills 45 people under age 50 in more than 200,000 cases — who now all have immunity — is as close to the dream virus as you can get.

Chaser: of the 460 total deaths from Delta, only 165 (36%) had not taken at least one holy jab. The rest loved CNN.

Anybody listening?

  1. The counter-example was the Spanish Flu during WWI. A virus is ‘looking’ for more hosts; men in the trenches who got mildly sick stayed in the trenches, while those that got more seriously ill were taken to hospitals. The mildly sick only exposed a shrinking population of non-immune soldiers (those who had not already caught and recovered from the virus) while those who got more sick and were taken to hospitals got a chance to expose many more non-immune people, both on the trip and in the hospitals themselves. Thus, this one time, selection pressures actually favored a more virulent version of the flu. In the big picture, this odd environment that selected for symptoms bad enough to get the victim removed from the front briefly made the Spanish Flu more deadly, before it, like every other virus in history, mutated itself out of the news. Or so the story goes.
  2. I’ve often wished I had gone into evolutionary biology – it’s endlessly fascinating. One idea I had as a kid when I first read and read about Darwin, a notion I have yet to find in the literature (not that I’ve done anything like an exhaustive search) is the idea that life has evolved to evolve, that any successful living thing – and that’s every living thing that exists – has a genome that has gone through millions upon millions of selection cycles. Genes that produce characteristics that provide an advantage only once every hundred or thousand or million cycles would still get selected for. Think of grasshoppers – they have the genetic hardware to become locusts, a behaviorally and physically different animal. Yet many generations may pass before whatever it is that triggers that transformation occurs. Those genes persist through many generations where they are not expressed. Why? Or hybrid vigor: why is it that when closely-related but long separated populations mate, the results are so many outliers? Hybrids are smaller, bigger, stronger, weaker, and so on, than their parents. Why? Well, what if selection pressures over millennia had favored rolling the dice, feature-wise, whenever sufficiently divergent populations interbred? The environmental question: what kept those populations apart, and what has changed to bring them together? When an evolutionary environment changes – meaning, definitionally, the selection pressures change – then whatever form was selected for in the previous environments may no longer be favored. Maybe a bigger version would be better – or a smaller, etc. So, coded into every genome by natural selection acting over millions of years is a hybrid function: the advantage goes to more varied offspring in an environment of unknown but different selection pressures. I don’t know if that makes any sense – I’d need 10,000 words or more to spell it out any better.

Author: Joseph Moore

Enough with the smarty-pants Dante quote. Just some opinionated blogger dude.

9 thoughts on “The Dream Virus”

  1. Excellent discussion of virus evolution! Thank you very much. One of the things that interests me about progressive types is that they are so sciencey and yet they seem to really hate evolution because it doesn’t produce the results they would want.

  2. Interesting piece, and you’ve made plausible case. You know (or maybe don’t) that the philosopher Thomas Nagel has said that evolutionary theory is incomplete. A teleological principle is needed (but “science” forbids teleology.)

    1. Absolutely, evolutionarily theory doesn’t quite work, because you can’t ever say what something is for – teleology. Further, few if any of its claims are actually testable in anyway. We end up with a large collection of just so stories, where the more extreme partisans think they have demonstrated something simply by means of coming up with a plausible account of how it might’ve happened. But do selection pressures have some effect on differentiating species? That’s all Darwin himself really claimed in origin of species. That much I am down with. It seems to be the most rational place to start, at least, until something better is proposed.

      1. And yet teleology sneaks in anyway, at least on the micro level. Viceroy butterflies evolved to look like monarch butterflies, so that birds wouldn’t eat them (not a great example because a careful biologist could explain this in a much less teleological manner, but this is how it comes to the kids in fifth grade. And even then, evolution is directed to the end of survival of the species). Anatomy textbooks will have chapters based on the different organ systems – even the reproductive system.

  3. The only thing I would add is that in England as in most places that have a vaccine available, older people are much more likely to be vaccinated than younger people. That makes for a greater fraction of cases in the young and healthy and therefore a lower overall case/fatality rate. I’d be interested to see the case/fatality rate for Delta broken down by age groups.

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