The added complexity with virus, compared to other pathogens is that it mutates very quickly. So the vaccines which are effective against the original strain may not work against the mutated strains. The good news is that so far none of the mutated strains have shown a very high level of resistance against any of the vaccines. But there is no guarantee that it will remain the same in the future. The only real solution is to vaccinate as many people as possible, as the virus can mutate only inside the human body.
That's Sci-fi BS, WHO already said that even if it mutates, the vaccines will still be effective because in the core, the virus is still the same. I do agree with you that more people should be vaccinated as fast as possible because it can help for a faster recovery of the economy.