Here is what I could read and understand about vaccines.
The vaccine will depend on the mutation rate of the surface antigen (Spike protein). Protein S gathers in trimers on the surface of virions and plays a key role in the entry of the virus into its target cell. After the advanced protein binds to the human cell receptor, the viral membrane fuses with the human cell membrane, allowing the genome of the virus to enter human cells.
We now detect three distinct variants of covid-19. Type A, B and C. I do not know if these mutations come from the S or L strains. Chinese researchers have also identified 149 minor variants among the 103 genomes analyzed. Indeed RNA viruses mutate much more easily and more quickly than DNA viruses, because with each replication, nucleic acids are poorly copied.
My question is: The result of the mutation of the surface antigen is therefore more likely to degrade, than to succeed in a new link mechanism and membranes fusion, since they replicate poorly?
I would even say that the virus is doomed to its loss.
But I have also just seen that the purpose of mutating the virus is to overcome the resistance of the human immune system.