[Cogito]

Not at all.

The effectiveness of a vaccine is related to the effectiveness of the bodies immune response to the virus.

As long as different mutations do not affect the effectiveness of a given immune response provided for by a vaccine, that vaccine will be effective against those mutations.

Mutations can affect many aspects of a disease, and often this means a different level of effectiveness of an immune response, but it really does depend on the specific mutation.

For now, there are no selection pressures on different strains from vaccines; it will be interesting to see what mutations become prevalent once testing of vaccines starts.

[sizzle]

Why does it take so long to develop a deactivated vaccine version of the virus to teach our immune system what to attack?

[Cogito]

Safety. You have to understand what 'deactivated' means for this virus, and that people won't get significantly sick if you feed it to them. That takes time.