Most news articles I see focus solely on the number of vaccinated people when estimating how far away countries are from herd immunity, which seems odd to me. Left out in the discussion seem to be the unvaccinated but already infected. As far as I know, prior infection confers at least some degree of immunity. It may also be the case that those inclined to be skeptical of vaccines were also the ones who exposed thems…
I don't know what the point of such conjecture is. Of course we don't know how much immunity comes from infection, and it is quite clear from the spread of delta that we are nowhere near herd immunity in the developed world, even in places like Israel. I had a coronavirus called a cold last year; does that mean I'm immune this year? Unlikely in the long term with COVID. The entire concept of herd immunity may be a mi…
There are supposedly over 200 different viruses that can cause the common cold (https://www.nih.gov/news-events/nih-research-matters/underst...). So it's quite possible for immunity to any individual strain to last a very long time and still get multiple colds per year.
> Usually viruses become more transmissible and less lethal in response to rational behavior in their hosts--but humans are proving we're not rational.
Our own "rationality" doesn't matter much, if a virus leaves you bed-ridden or dead, that makes it very hard for you spread it regardless of your choices. The fact that we have so many different viruses which essentially cause more or less the same "common cold" proves that there is very strong evolutionary pressure for a virus to behave this way.