Due to the nature of the virus the vaccination is pretty good against the known variations. And can be imagined to be pretty effective against future unknown variations too.

The vaccines aim to enhance the immunity system to detect and counteract the spiky bits of the virus, which are the part that it uses to attach to the cell surface. There are only limited number of configurations in the protein spikes that are effective for attaching to human cells, if the virus mutates the spikes too much they are useless for that purpose.