The reason mild variants have done well in India is because they have fewer attendants to do artificial selection. It has nothing to do with lockdowns. Matt doesn't have the brains to know what he is saying.
What "mild variants"?
GenBank etc show theres nothing functionally (or at all) different to the lineages around the rest of the world. Certainly no functional changes.
India has a very young population and age is by far the biggest severity indicator.
Could also be genetics, cross-immunity. But its not variants.
A non-working lockdown may well help. No selection pressure to evolve.
Certainly artificial selection is a real thing. But no mechanism of action is given to suggest lockdown gives artificial selection towards more severe covid19. It's codswallop, read the ridley article, it make no sense.
No its not.
You're lacking even a GCSE school level of understanding here.
We're creating selection pressure through things like social distancing.
Therefore the variants that are better able to spread in those circumstances will out compete those that aren;t.
For example B.1.1.7 although mechanism uncertain showed a greater viral load. As infection is linked directly to viral load this means more of it is going to get further and infect more people.
"Severe" means nothing to a virus. It doesnt give a toss if the host ends up dead after the infectious period. Mutations that increase infection and load can easily have the effect of making the host sicker and less likely to recover long term.
Mutations that hinder the immune system for longer or more permanently will also favour viral survival whilst at the same time rendering a host sicker or dead.
Countless examples where it can and does happen for that.
Things like the lung scarring etc - most likely helps viral spread initially and in doing so causes huge damage to the tissues and more likely to be severe to the host.
There are plenty of physiological changes that (i) help the virus and (ii) are worse for host.
As long as that damage happens after the infectious window, it'll have no effect at all on the virus selection variants.
Natural selection drives evolution to optimal points in two directions 1) highest transmissibility 2) lowest lethality.
Except that isn't actually true. Its a general trend but there are many, notable exceptions.
The virus doesn't care about lethality if it happens after the infectious period.
If a virus makes physiological changes that increase infectivity but leave far more severe damage after its gone it doesnt matter. Its job done.
A used host is irrelevant.
This is why India and China with huge populations now have virus variants with highest transmissibility and lowest lethality.
Except they dont. Look on NextStrain. Functionally the variants there are no different to the ones found elsewhere.
The reason mild variants have done well in India is because they have fewer attendants to do artificial selection. It has nothing to do with lockdowns. Matt doesn't have the brains to know what he is saying.
What "mild variants"?
GenBank etc show theres nothing functionally (or at all) different to the lineages around the rest of the world. Certainly no functional changes.
I see. I was referring to Matt Ridley's article, where he says the slew of mild cases in India is somehow related to attendant-borne artificial selection. saying ‘it’s pretty generally accepted that in India, we have a very mild form of the virus’.
https://www.spectator.co.uk/article/stresses-and-strains-the-evolution-of-covid-is-not-random
check it out and let us know what you make of it.
I've read it and its more his wording.
Milder progress of disease would be accurate. Milder "form" is demonstrably untrue from NextStrain and other data. Shows clearly there are no genetically different variants circulating in India than elsewhere in the region or in fact world.
The lack of any form of distancing means there isnt as much benefit for a strain thats better infecting with less exposure but ultimately with India the age demographic is likely to be a huge affect.
Younger people get less sick and die less.
Average age Africa: 19.7
Average age Philippines: 25.7
Average age India: 26.8
Average age UK: 40.1
Average age EU: 43
Age plays a huge role:-
https://www.nature.com/articles/s41598-020-73777-8
https://www.sciencedirect.com/science/article/pii/S0013935120307854
Ultimately 16-100 fold death increase risk going from 20 to 65.
Roughly 5% of India population is >65. Thats 12.5% or so in the UK or example.
The younger a population, the less they're going to be affected.
It won't be the only thing but will be a significant contributor.
