The problem is, the vaccine doesn't fix the problem. At the moment, given the variability of the virus, the appearance of mutations, the vaccine will not give massive immunity. And it will be very good if in the next 2-3 years a set of vaccines is developed that will "block" most of the mutations, and only then the pandemic will stop .... And only then it will be possible to talk about the restoration of the global and local economies. Therefore, to our great regret, we need to prepare for a few more years to live in the same conditions as today, if a miracle does not happen. Good health to all!
The vaccine works to stimulate the immune system, more precisely - the production of IgG (specific antibodies) against the S-protein. What's important to understand is that antibodies, that are produced during the immune response are polyclonal, which means that there are different antibodies that bind to various regions of the S-protein.
Say, some mutations take place, but they happen locally and can lead to changes only in some parts of the protein, while other regions will remain as they were, which means that there still will be antibodies, that can attack the S-protein.
Now, in the worst-case scenario, the mutations will be so frequent and severe, that they will change the structure of the S-protein completely. But now let's remember, that S-protein is the very protein, that is necessary for binding to receptors on the cells in order to penetrate them. Therefore, if the S-protein changes too much - the virus won't be able to penetrate the cells and, therefore, won't cause any harm.
Conclusion: mutations either won't be too serious and the immune response received from the vaccine will work, or they will cause too many changes in the structure, due to which the virus won't be able to attack the human organism anymore.
So not to worry, it's going to be alright