Nature would always prefer less lethality and greater transmissibility.
Nature doesn't "prefer" anything.
If there's a selection advantage for something to happen it'll be selected for. If there's a disadvantage it'll be selected for.
Lots of changes are selection-neutral and the disease is in equilibrium. R0 remains unchanged, IFR remains unchanged for 100s or 1000s of years.
So its a specific problem for ONE vaccine - the others can cope for now well enough.
The problem is the UK is basing almost its entire response on the Oxford/AZ.
I'm afraid that is driven by logistical imperatives. One would assume a tenable response would be to alter the mix, at least as soon as (say) moderna vaccine floods in and to adapt the oxford vaccine to the new target as quickly as practicable.Until then, and while the SA variant remains uncommon, it is correct to continue with what is available for the time being.It is unavoidable that some ground must be given up.
With SARs2, the infectious period is relatively small, typically a week on average at most.
People on average take 3-4 weeks to die. They're not infectious for the last 3-4 weeks.
I didn't know that. I assumed people were infectious right through. You learn something new every day
And so I missed the key part too . . . .
So selection wise its irrelevant. Once a host is no longer infectious theres no selection pressure there at all. You can discard it, throw it in the bin. It has no effect.
Indeed 😉
Nature would always prefer less lethality and greater transmissibility.
Nature doesn't "prefer" anything.
Yes OK Splatt, I'll defer to Charles Darwin and say "Nature would always FAVOUR less lethality and greater transmissibility." On the Origin of Species BY MEANS OF NATURAL SELECTION, OR THE PRESERVATION OF FAVOURED RACES IN THE STRUGGLE FOR LIFE.
Favour , since you prefer ... it's nomenclature.
If there's a selection advantage for something to happen it'll be selected for. If there's a disadvantage it'll be selected for.
Lots of changes are selection-neutral and the disease is in equilibrium. R0 remains unchanged, IFR remains unchanged for 100s or 1000s of years.
A reasonable hypothesis is that Lockdowns cause mutations to more severe forms by hindering the natural evolution to milder forms.
No, that is not a reasonable hypothesis, as it stands since dead hosts do not transmit the disease, only living ones, which milder forms encourage. Lockdowns may slow the evolution whatever the direction, but would not tip the evolution either way. The direction of the evolution is biased towards variants that spare the host, and against variants which kill the host. Splatt would argue that lockdowns bias the evolution towards more transmissible variants, but that is an independent property.
Stress speeds evolution. Lockdown produces a stress that favours highly transmissible variants. I.e. due to the lower contact levels the variants better at transmitting are more successful and become dominant. The answer is either hermetically seal everyone or don't lockdown. I favour the latter but encourage those terrified to hermetically seal. Yes, if the death rate was 10% including the young I might have a different opinion but it's not, it's <0.2% and an average age of death not much different to normal.
