## Sunday, April 04, 2021

### Virus, bacterium species have to fight for survival, too

...and almost all of them lose this battle...

I was immensely bothered by an anonymous user's comment under my analysis of the Czech population pyramid and Covid-19.
Traveller wrote: Any mention of "natural" herd immunity should have a mandatory disclaimer that, to date, the only ways humans have acquired herd immunity against any virus has been via vaccines.
The claim that this troll wants to make "mandatory" is dumb beyond imagination but at the same moment, you can detect quite some incredible amount of arrogance in the simple sentence. If she or he had tools to do so, any scientifically literate comments about viruses and bacteria would be banned. This is no funny business.

Joseph Stalin (right) de facto banned all of genetics in the Soviet Union (as a capitalist pseudoscience) and even Czechoslovakia, the place where Řehoř Mendel found the laws of genetics, was affected by this insane bastardization of life sciences. At least, Lysenkoism that was encouraged (Trofim Lysenko speaks on the photograph, far left) was a version of Lamarckism, a not too distant cousin of Darwin's correct theory. (Recall a funny question about virgins that the great physicist Lev Landau asked to Lysenko.) This troll would like to ban Darwin's evolution along with all the conceivable relatives and all of common sense in her or his country – and maybe globally. We simply mustn't allow the likes of Stalin to do things that he has done against the dignity, freedom, and survival of the people and the fundamental pillars of the civilization.

Fine. Why is this user's comment dumb beyond imagination? Let us reformulate the comment in another way:
Traveller effectively wrote: All viruses and bacterium species causing diseases in humans are entitled to survive forever and a vaccine is the only exception that may cancel the entitlement and drive the disease and the underlying virus or bacteria to extinction.
Do you really believe this? The first vaccine – weakened smallpox – was prepared by Edward Jenner 225 years ago, in 1796. Since that time, vaccines have been created and massively distributed against a bunch of diseases only – smallpox and MMR (measles+mumps+rubella, a mandatory stuff in the U.S.), chickenpox, shingles, polio, rinderpest ... and just a few more (see a page on eradication of diseases). Let us call it a "dozen of diseases". Do you really believe that all diseases (and viruses and bacterium species) that have ever terrorized mankind are still around and terrorizing mankind, except for one dozen of diseases that were eradicated by vaccines? Do you believe that while Covid-19 has produced significantly new variants in a year, the remaining body of infectious diseases has been the same for millions of years in which the "homo" species existed? Do you really believe that thousands of other diseases (or more) haven't emerged during the life of the human race even though we've seen several new infectious diseases just in one decade?

If you do, you really believe that up to some recent paradigm shift that took place 225 years ago, viruses and bacteria were exempt from the natural selection and the need to fight for survival; and you also believe that the evolution of new species and variants has been non-existent for millions and billions of years (and is at most a recent phenomenon). Why would you believe such a thing that self-evidently contradicts the insights about life on Earth that fifth-graders should already perfectly understand?

Extinction has always existed and the rate has arguably sped up. By some estimates, the extinction of species occurs 10,000 times more often than in the past. I doubt it and the qualitative conclusions in no way depend on this "anthropocene" speedup (which may be completely non-existent, as far as I can say). The Earth is losing between 1/10,000 and 1/1,000 of the existing species each year. Dodo (whom we call Cretin the Inane One, "Blboun nejapný", in Czech) has been gone, too. But viruses and bacteria get an exemption from "Traveller". As long as the hosts are around, the carriers of diseases must be with them, too (and maybe they also get a pension and are protected against microaggressions). Really?

No. It's complete, flabbergasting nonsense.

A virus or a bacterium is a parasite. When a virus or a bacterium is harming one's quality of life (and they often use "resources" that the host may use in a more useful way) or increases the risk of premature death, it is a problem. The host must better fight against it. Because humans haven't gone extinct yet, it's been always possible to produce some weapons to deal with the fatal enough infectious diseases. That's what the immunity system is supposed to do. It's an important collection of organs, cells, and molecules that a human being (or any other advanced enough organism) possesses. It plays a similar role as the army plays in the life of a country. You should better have one, otherwise you may be captured, eaten, destroyed. All countries that had no armies are gone by now.

The survival is a pretty important stuff so Nature has developed and had to develop a pretty elaborate set of components of the human immunity system. The organs include mucous membranes in nose and throat; tonsils; lymph nodes; thymus; spleen; bowel; mucous membranes in bladder and genitals; bone marrow; and, indeed skin. The blood cells whose job is "immunity" include monocytes; lymphocytes (of many subtypes); neutrophils; eosinophils; basophils; macrophages; erythrocytes; platelets; blood stem cells and 12 types of "descendants" in its tree. And then molecules: antigens; antigen presenting cells (APCs); antibodies; and dozens of other categories of molecules. The system is really similar to an elaborate amy that has tanks, people who produce tanks, espionage agents, their cooks, and add dozens of other occupations that an army involves.

The interaction of a harmful virus or bacterium with the human being (or another organism) is a big battle or a war, like so many other battles in Nature. Nature is composed of these processes. A tiger sees a buffalo or an antelope. They run. One of them is faster. It matters who is faster. Yes, some animals kill and eat other animals, even healthy ones. I won't apologize if I have just destroyed your day or the illusions about your whole life on Earth. ;-) The result of any of these struggles just can't be predetermined. If one side of such battles were a clear loser, it would have gone extinct and it wouldn't be around and we wouldn't be talking about it now. All the battles that remained relevant for a long time are unavoidably close to "close calls". It's exactly the same when the human immunity system deals with an infectious disease. The result isn't predetermined. Everyone who thinks that such things are predetermined – and only a bureaucrat with a miraculous modern cure and an obedient electorate composed of human sheep can change the predetermined outcome – is a flabbergasting idiot. I am immensely annoyed that we allow such idiots to walk on the street. We may even sometimes allow them to enter the university buildings or appear on TV screens or post comments on TRF. It is absolutely shocking and I will never get used to this proliferation of incredibly stupid people, especially if they are aggressive at the same moment.

OK, the interaction between a virus/bacterium causing a disease and the hosts is a huge war. And the war has many components that deal with different time scales. Some battles are short-lived but some problems persist and they are dealt with by more long-lived parts of the immunity system etc. Some of the very long-lived parts of the immunity responses are "owned by the whole host species". We can see on this Covid-19 how it's essential for the sides to adapt themselves. Humans clearly started to develop an immunity. The virus luckily mutated because all generalized life forms do so. Instead of the apparently clear decay in January, we added over 2 months and we are only seeing a clear enough new decay in April 2021. The British mutation has increased R0 by a factor of 1.5; the Brazilian mutation has emerged that is approximately 50% invisible to the immunity gained for the older variants, therefore giving some new life to the epidemics in many countries. This is the speed at which the fighting sides have to adjust themselves if they want not to get extinct (only SARS-CoV-2 is threatened by extinction in this case, the human race clearly isn't). Such things have occurred in all previous encounters of diseases and their hosts. For every disease that has existed in the past that wasn't stopped by the mass vaccination, its almost complete non-existence means that the humans have naturally won the war. If you believe, as the recent experience suggests, that several similar diseases appear each decade, mankind has surely naturally defeated at least thousands of such diseases.

Here you can read a BBC page about the viruses that just naturally disappeared without trace. That is what most viruses do. They are defeated, like a new species related to antelopes that lived around tigers and was too slow. A very recent example of a virus that disappeared without a vaccine and without a trace is SARS-CoV-1, you know, the first new coronavirus that was way more deadly than Covid-19. We have never had a vaccine against it but it has just disappeared, after thousands of known cases in dozens of countries. In the BBC article, an epidemiologist carefully states that the virus disappeared due to a combination of sophisticated contact-tracing and quirks of the virus itself – that just didn't turn it into a survivor.

Of course Covid-19 may return to some non-vaccinated and previously unexposed communities or subcommunities, so it could be around for years or much longer. (The negative correlation between the Czech or other regions or districts that were highly Covid-active in the past; and that are Covid-active now, is incredibly obvious and reliable, thousands of similar predictions pass highly nontrivial tests.) But it may also disappear. If you just look at the Swedish Covid-19 statistics page, you must clearly understand that this is the ultimate example of herd immunity in action. The death graph in the right lower corner shows two very similar bumps or waves, each of which killed some 6,800 Swedes, mostly in a 3-month-long period (in both waves). The herd immunity acquired by the Swedish nation in Spring 2020 just wasn't enough for the "winter season" when it's easier for the disease to propagate. But now they have the herd immunity against that, too. The total excess deaths are indistinguishable from the statistical noise. I am sure that they will already be seeing a "deficit" of deaths for April 2021 because Covid-19 has already killed many people who were "ripe for death" due to other causes now.

SARS-CoV-1 and SARS-CoV-2 are not the only viruses causing infectious diseases. We also have the flu. Well, most of the flu strains that have been around are gone, too. Here you have a 2011 paper claiming that Memory B cells are an important player behind the natural elimination of the strains of flu. The paper has over 100 citations by now. Even if the details were wrong or incomplete, it is unquestionably true that uncountably many strains of flu have disappeared naturally. And so did most infectious diseases (and their carriers) that have ever jumped on animals that walked on Earth (or flew in the air). The human ones are just a tiny fraction of that set. Other animal species have their immunity systems and herd immunity, too.

It's hard to know whether people like "traveller" really believe the immense stupidities that they spread – like the meme that "infectious diseases can't ever be driven to extinction naturally". I think that all these people are so fanatical left-wing radicals whose actual goal is to completely eliminate the human freedom (and to become rich, powerful, and would-be important along the way) that they are completely uninterested in science and they have absolutely no problem with lying 24 hours a day and 365 days a year (and indeed, it was 366 in the year 2020) – and they enjoy bullying people who dare to know some science or think rationally. They're scum that is wildly more dangerous for mankind than Covid-19 or another flu-like disease. It is very clear that our civilization will either completely kill Covid-19 or it will become a very small problem that will at most be comparable to what flu has been for decades. The transition to that state is already happening (and the Covid-19 vaccines are massively more efficient than the flu vaccines – the latter are only about 35% effective). But the likes of "traveller" may really destroy science, the human civilization, and they can even drive the human race to extinction. I find it pretty clear that most of them want this outcome.