Well, sure. I oversimplified. I think we are saying the same thing.
This from last OctoberGreen Pimble wrote: ↑Sun Feb 21, 2021 3:40 amI feel an argument could be made the other way: if certain symptoms cause someone to be isolated from others (via self isolation or govt. policy), you could say the selection pressure on a virus is to become less dangerous/less symptomatic, so the virus may spread and not end up in an isolated host.
I don't know if COVID-19 and its variants tend one way or the other, but I would be cautious in linking social isolation to more virulent strains.
https://www.sciencedirect.com/science/a ... 7920318649
And this from early February in Nature....the virus hasn't needed to evolve in order to be successful. Not yet, anyway. This is what makes some virologists nervous as we move into the next phase of the pandemic.
As a rule, evolutionary adaptation happens due to “selection pressure”, which is when an organism's environment changes to favour certain variants over others.
Right now, SARS-CoV-2 is under very weak selection pressure. There are still plenty of humans to infect who have no “immune memory” to fight the virus; there are very few drugs to evade; and there is no vaccine. But as these benign conditions become harsher for the virus, selection pressure will ramp up and we can expect to see it evolve in response, perhaps in ways that make it even more dangerous.
https://www.nature.com/articles/d41586- ... c-42375251
ETA, a few weeks ago I read a paper that explained why the conventional wisdom holds that viruses mutate to become less deadly. In it the authors argued that the viruses we encounter are either stopped right away or they run wild and never encounter significant selection pressure. So, they are either stopped before evolving or they spread so well that they don't need to evolve increased virulence.On 3 February, researchers at the London School of Hygiene & Tropical Medicine (LSHTM) released an analysis1 of some of those data, which suggests that the risk of dying is around 35% higher for people who are confirmed to be infected with the new variant.
The team found that B.1.1.7 is more deadly than previous variants for all age groups, genders and ethnicities. “This provides strong evidence that there indeed exists increased mortality from the new strain,” says Henrik Salje, an infectious-disease epidemiologist at the University of Cambridge, UK.
Our half-measure response to Covid may have given the virus just the right amount of selection pressure.