Re:Omicron variant was 73% of U.S. covid cases last week
by bruce511 on Tuesday December 21, 2021 @03:03AM
(#29635084)
It's obviously mutating all the time. But if a particularly lethal version mutated into being it would quickly kill the host, thus not spreading far, if at all.
Thus natural selection optimises for forms that spread but don't kill.
Re:Omicron variant was 73% of U.S. covid cases last week
by jacquesm on Tuesday December 21, 2021 @03:36AM
(#29635281)
This is simply incorrect. There are plenty of viruses that end up with an intermediary grade that may well have very high lethality. Once a virus has spread what happens to the host is irrelevant, including death. See May and Anderson's paper from 1982: Coevolution Of Hosts and Parasites.
https://www.researchgate.net/publication/224043344_Coevoluti...
DOI:10.1017/S0031182000055360
Re:Omicron variant was 73% of U.S. covid cases last week
by Xylakant on Tuesday December 21, 2021 @03:06AM
(#29635100)
> Thus natural selection optimises for forms that spread but don't kill.
It may also find an unlucky local optimum where it shows no symptoms for a period while already being highly transmissible and then slowly kill or leave the survivors with permanent damage.
Re:Omicron variant was 73% of U.S. covid cases last week
by bruce511 on Tuesday December 21, 2021 @03:19AM
(#29635177)
This is part of why AIDS is so bad. We're just lucky that AIDS is hard to catch outside of well understood behaviours.
Mix AIDS with Omicron and you can stop bothering to save a pension.
There are no goals, paths or planning in evolution, evolution is the result of chance. Selection pressures are what keep the effects of genetic mutation in check. The selection pressure that might cause a virus to become weaker is the result of the virus literally dying in all of the corpses it creates, while weaker strains potentially live on in the hosts they didn't kill. People aren't dying in droves because of COVID, so that selection pressure doesn't exist, and the virus is free to mutate into more virulent forms.
Also, evolutionary timelines span many, many human lifetimes. In that time, a virus could very well become more fatal, wipe out entire species and die off itself like the majority of species in the history of the Earth, or it could become endemic in a different species afterwards and live on.