Some of foremost vaccine companies and medical experts in the world all but promised the COVID vaccines would give immunity to the disease and prevent it being transmitted.

So they really have far less of a grasp of vaccine effects in even that a very narrow situation than you would think. So I don't think you can just put this to bed with a few sentences starting with "it shouldn't happen"!

Are you saying that because the number of possible signatures is so vast and the vaccines so specific, even if they get slightly broader it isn’t going to make things worse because in the grand scale of things we aren’t really walling too much off?

I'm saying that at most using the vaccine will cause a virus to evolve that it evades the vaccine. It won't get any other supervirus properties, become worse, or otherwise change. The concern with using antibiotics (for instance) is that a bacteria becoming immune to one becomes more resistant to all and it's hard to generate new antibiotics. On the other hand, with the vaccine, you just might need a booster with a different signature. There's no "broadening". It's just different.

So, a vaccine's immunity might not last forever. And?

To the contrary, viruses are not intelligent, when mutations happen at random, the best way to prevent mutation is to prevent infection and length of infection.

That makes a lot of sense, thanks for the explanation!

I think what they are saging is that something that kills perfectly, every time does not generate selective pressure. The virus would have to lose the signature completely randomly.

Whereas antibiotic resistance is something that could develop because antibiotics could be under doses so individuals survived partial exposure or perhaps they worked by a mechanisms which already had some resistance in the population.

It's like, you can breed high lung capacity mammals by having them live in water but you would just kill the species if you jumped straight into holding them underwater for 20 minutes.

Something has to be survivable to genetate selective pressure.

In that case, shouldn't we never give vaccine to people with poor immunity system or with immunocompromised condition, and rather just let them be or even die? If this is true (even though difficult to actually implement in the society due to humane consideration), what happens to the vaccines of viruses like HIV? The patients already have weak immune system.

I guews if you were blindly trying to breed the most durable individual specimems. But humams have major adaptatioms aside from immunity. We have cooperation and the ability to help each other. Is it worth it to let the town butcher or carpenter keel over to secure a small increase in generarional immunity?

Native Americams had no choice but to go the route of inherited immunity when they began contracting Eurasian diseases. Was it worth living through a literal apocalypse to gain immunity?