Omicron and Evolutionary Biology: A Greek Tragedy in the Making.

Posted on | November 29, 2021 | Comments Off on Omicron and Evolutionary Biology: A Greek Tragedy in the Making.

Mike Magee

“Many still see Alpha and Delta as being as bad as things are ever going to get. It would be wise to consider them as steps on a possible trajectory that may challenge our public health response further.”
Aris Katzourakis, Evolutionary Biologist, University of Oxford., August, 2021

The prophetic words above were shared just three months ago in a Science review article on Covid variants. Now we’ll have to deal with Omicron, and (who knows) Pi in the wings somewhere.

Let’s review the Covid mutants:

Alpha – A variant first detected in Kent, UK with 50% more transmissibility than the original and has spread widely.

Beta – Originating in South Africa and the first to show a mutation that partially provided evasion of the human immune system, but may have also made it less infectious.

Gamma – First detected in Brazil with rapid spread throughout South America.

Delta – First seen in India with 50% more transmissibility than the Alpha variant, and now the dominant variant in America and around the world.

Omicron – Labelled by the WHO “a variant of concern” because it has 32 mutations of the original Covid spike protein that drives transmissability. The Omicron warning: “There could be future surges of Covid-19, which could have severe consequences.”

The silver lining: Our ability to track and identify mutating viruses in real time is now extraordinary. Well over 2 million Covid genomes have been cataloged and published. But describing the “anatomy” of the virus is miles away from understanding the functional significance of their codes, or the various biochemical instructions they may instruct.

These deeper questions are in the realm of evolutionary biologists who are currently experiencing sleepless nights. Their prior nightmare? “What comes after Delta?” No need to wonder any longer. It’s “Omicron.”

As we await scientific analysis to catch up on the new variant, what we already know is that Delta’s genetic mutation, P681R, affected a spot on the virus spike that cuts through protein chains and sped up human cell entry 1000 times. The speed lit a fuse under colony growth, which in turn allowed the virus’s spread to other unsuspecting human contacts before any immune response generated symptoms appeared. Of course the state of being asymptomatic didn’t last for long. Speedy virus multiplication rates accelerated the microbes movement from upper airways to lower airways.

Will Omicron be a killer? First a few basics.

1. A virus’s survival, and threat to us, relies on three factors:

a)Infectiousness, b) Virulence, c) Immune Evasion.

But these factors can as easily play against each other as for each other. Natural or vaccine induced immunity slows down infectiousness and potential virulence. But (by narrowing a virus’s options for survival) it also creates a Darwinian reward for any mutant that figures out the Rubik’s Cube solution to becoming “invisible” to the human immune system. According to Rockefeller University virologists, such a change requires the coalescence of 20 independent random changes in the genome. Bottom line: Random escape is a tall order. But Omicron already is housing a boatload of mutations on the infective spike. And with Delta having burned through a sizable portion of its potential future victims, Omicron stands expectantly in the wings.

2. Viruses depend on us. But we no longer look or act as we did in 2019. 4.3 billion citizens (56% of the global population) worldwide have had at least one dose of the vaccine, and hundreds of millions of others have survived the infection. The virus each day is increasingly pressured to find its next human victim. One way out is to figure a way past our immune defenses provided by prior infection or vaccination.

So this is a cyclical game, likely to go on for some time. If we global citizens played our vaccination cards better, the virus would have had fewer turns in the game, and the appearance of Omicron would have been less likely. But here we are.

So here are five take-away facts:

The longer we allow Covid to stick around, the worse this could get.
The majority of the messy replication mistakes are inconsequential, but there are occasional windfalls that rise to Greek alphabet mythical status. Omicron is likely one of them.
Delta’s critical weakness – it leaves behind high antibody titers that limit its future.
Give the virus more time, or access to compromised hosts, and anything can happen. Viruses are constantly rolling the evolutionary dice.
Mutations hurt us by increasing transmissibility/virulence or immune evasion. The good news is there is some evidence that an immune escaping Covid might not be efficiently transmissible any more.

Leaders who still politicize this virus are not only ignorant of evolutionary biology, they are playing with fire – and with our human lives.

Whatever it takes, we need to force this virus into a corner . That means a worldwide vaccination push. Otherwise, we run the risk of becoming a Greek tragedy ourselves.

#IgnoreDeSantics