I'd find it helpful if you provided some thoughts on determining what's reasonable and what's not reasonable to expect from future variants. As I understand it, a virus dramatically changing its mode of transmission -- say going from respiratory to a hemorrhagic fever -- doesn't really happen. But we also have a decent understanding of how covid gets transmitted now, so have some way to anchor expectations. You're saying it's not reasonable for covid to evolve to become more likely to cause illness in children. If that's true that's great news, but I really have no way to evaluate such a claim. Why is that unreasonable? Wouldn't we need more insight into why children are currently less affected to speculate on how reasonable it would be for that to change?
I notice your profile you have a biology background. I don't, and am guessing most people here don't either, so I'd find it helpful to get an explanation of why you find a change that puts children at more risk unlikely (and I bet others would too).
> You're saying it's not reasonable for covid to evolve to become more likely to cause illness in children. If that's true that's great news, but I really have no way to evaluate such a claim. Why is that unreasonable? Wouldn't we need more insight into why children are currently less affected to speculate on how reasonable it would be for that to change?
The short answer is that evolution is random. It isn't an intentional process. The virus isn't trying to become more infectious, or deadlier, or...anything, really. It's just a random process, filtered by some outside force(s). And in this case, the relevant outside forces acting on the virus are: 1) the human immune system's ability to see the virus, and 2) the virus' ability to bind to our cells.
If you're vaccinated (but not previously infected), your immune system can basically only efficiently recognize a bunch of little chunks of the spike protein of the virus -- the piece that allows the virus to bind to your cells. So any random mutations to that spike protein are potentially beneficial, in that they can maybe hide the virus from your immune system, or maybe increase how tightly the virus binds to your cells, or they can be potentially detrimental, in that they can maybe cause the virus to bind less tightly to your cells, or make the spike protein misshaped or something. Or they can do nothing at all.
These are essentially the only "forces" related to vaccines that are guiding the evolutionary process: forces that attempt to change the structure of the spike protein to either escape the immune system, increase cellular affinity, or decrease cellular affinity. The vaccines do nothing to influence anything else. All other dimensions are random, with respect to the vaccine.
Viruses are pretty stupid. If you want to imagine that the virus could become "more fatal" (somehow; it's not clear how this would happen), it has to be done within this framework. There was to be some process that is selecting for the viruses that are "more fatal", and that process needs to be somehow more efficient when only a fraction of the human population recognizes the little bits of the spike protein encoded by the vaccines.
Can this happen? Sure, anything is possible. Is it plausible? No, not really.
I notice your profile you have a biology background. I don't, and am guessing most people here don't either, so I'd find it helpful to get an explanation of why you find a change that puts children at more risk unlikely (and I bet others would too).