> How would that POSSIBLY work?
Through a process called V(D)J recombination [2]. Essentially, every lymphocyte gets a different receptor of random shape, and purely by chance there will be a few lymphocytes with a receptor that matches the shape of the invading viruses (in most cases).
But the poster I was responding to was claiming that our immune system should have evolved the ability to not respond to those threats, but anticipate their specific forms without seeing them. That vaccination as a concept is hogwash because if it was useful, we'd have done it through evolution. But that's plainly nonsensical - we wouldn't need a system that functioned by random variation if we evolved the ability to know what the real targets would be, but we couldn't do that without specific knowledge, which we can't get without being exposed to the things, by which time ... it's too late to have then already built the specific defenses.
See my response to another comment. We must have dealt with countless species and strains of coronaviruses already. So, our genes have a lot of training they need. Even if we haven't trained for this particular strain or species, we will most likely fare better than the solution that has never been tried ever.
What if the children of those vaccinated turn out to be much weaker against other common antigens start dropping dead? It will set humanity back by a lot.
These are not exaggerated hypotheticals. These are VERY REAL possibilities: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5607155/ https://www.ncbi.nlm.nih.gov/books/NBK233000/
>since people don't already have immunity, so your "millions of years" thing is completely off base.
We do. Most people are completely unaffeted by the virus. It's a relatively small percentage that has severe problems. To endanger EVERYONE because a small percentage is affected is downright retarded. Having said that, I'm not at all against trying different things out. The best way to roll it out would be to do it over a VERY LONG PERIOD, spanning generations. And most importantly, keeping significant number of people completely unvaccinated. This has not been a problem until now because big enough population chose to be unvaccinated. However, the scale of current problem might mean that this could change... which is terrifying.
We'd have naturally evolved the ability to train our immune systems against specific things it hasn't seen before? How would that POSSIBLY work?
The novelty of this particular coronavirus is sort of the problem here, since people don't already have immunity, so your "millions of years" thing is completely off base.
You seem to be arguing against the possibility of a "universal vaccine" for all viruses but that's entirely not what this is. It's very specifically targeted and the idea that we'd evolve the ability to target things specifically without actually being exposed to them in the same way is plainly nonsense.