mRNA vaccines are difficult and expensive to make. Other technologies are cheaper.

The ones you had to wait for in the west were mRNA vaccines. They are newer, more complicated, and in theory customisable to a wider range of infections. While I'd love to see these opened up and used for their full potential I can see why the pharma corps don't want that.

While I haven't looked, I'll bet that the Cuban ones were"simply" using a deactivated virus - which is less effective and especially less effective against mutated strains.