And if that's true, it seems very likely that a vaccine have issues... if an active immune response isn't enough, I don't see how a vaccine would work. I suppos

And if that's true, it seems very likely that a vaccine have issues... if an active immune response isn't enough, I don't see how a vaccine would work. I suppose you'd have to administer it in spaced doses like with other vaccines, but that doesn't bode well for resilience against mutations.