The 'spike protein' is what the mRNA vaccines order your own body's cells to manufacture. The vaccine also encourages the body to attack that protein.

If the new variant of the spike protein is sufficiently different, then the antibodies created by the vaccine will not recognize it as a target, and thus the vaccine would have no protection against it.

However, when your own body fights off covid-19, it isn't limited to targeting just the spike protein. It targets a variety of proteins. It is likely that your natural immunity will be much much better at fighting off mutations for that reason.

The vaccine will be a disaster. It encourages the virus to mutate because of the narrow focus of the target. To do a mass vaccination in the middle of a pandemic is also stupid unless your real motivation is to create mutations.