No vaccine for
any infection guarantees you won't get it again - the purpose is to reduce the risk and severity.
The Corona virus is similar to the influenza one and will mutate especially while it is infiltrating a new host.
In time it will be like the 'flu - get the annual booster.
I actually got real Tetanus some years ago, but about a month after my last booster shot, and all I needed was a course of the right antibiotic. However, I know have 10x the basic immunity level usually achieved and can't have any more Tetanus boosters...