Flu vaccine doesn't seem to be very effective either
Nope. Not particularly. I think it's about 50/50, because they have to guess at the two most common strains, and hope that there's not much mutation going on before it hits the targeted hemisphere. But as prone to mutation as influenza is, coronaviruses are many times more prone to mutation, which is why medical science has never before even attempted a conventional vaccine for it. By the time you have most people vaccinated, it will have already mutated, requiring a new vaccine.
