That is not how the immune system works. There is lots of info about it and it is very complicated, but stuff that has been around for literally ages, that coincided with humans evolutionary path, have been basically added to a permanent watch list and so our immune system goes haywire at the slightest hint of one of those invaders presence. Covid is still considered a novel virus, regardless of it being a few years since it’s existence, and our immune systems haven’t had time to find a good defense against it. This is a simplification, but think of covid or other viruses like a key, but a rapidly changing (mutating) key and the immune system as a really elaborate lock, that also changes (but incredibly slowly, comparatively) and yeah that’s all I’ve got. Source: I’m in undergrad studying to be a microbiologist.
That is not how the immune system works. There is lots of info about it and it is very complicated, but stuff that has been around for literally ages, that coincided with humans evolutionary path, have been basically added to a permanent watch list and so our immune system goes haywire at the slightest hint of one of those invaders presence. Covid is still considered a novel virus, regardless of it being a few years since it’s existence, and our immune systems haven’t had time to find a good defense against it. This is a simplification, but think of covid or other viruses like a key, but a rapidly changing (mutating) key and the immune system as a really elaborate lock, that also changes (but incredibly slowly, comparatively) and yeah that’s all I’ve got. Source: I’m in undergrad studying to be a microbiologist.