Coronavirus immunity, mainly based on animal studies, has generally been taken as a matter of months. And you have to differentiate between t-cell and antibody immunity.
One thing most people don’t realize is that additional cv infections tend to sensitize the immune system and result in subsequent illnesses being worse. This is why the booster shot is being linked to a greater degree of side effects. In an extreme case you get sensitization to an extreme degree, such that a cytokine storm occurs and possibly death. This was seen in animal studies 15 years ago. This is one reason I don’t want the vaccine: more immunity ==> possibly fatal reaction to an otherwise moderate illness. Also called Antibody-Dependent Enhancent (ADE).
This doesnt make sense on its face. That means that your immune system would always be a ticking time bomb for any infection -> this does not happen.