Vaccination implies a vaccine has been developed. We haven't even created a vaccination for all the diseases we have, why would you expect them to? Or the resources and willingness to apply it. Vizima only seemed to have two mages, period. One was a politician, the other a genocidal madman. Which one do you think would be a capable medical researcher? Might it be the one who secretly went on about how the plague was "going exactly according to plan MUAHAHAHAHAHAHA."
They certainly have magical vaccination available for some diseases.
W-HAT
I got cover before I ever used intimidation. I had no idea how I got it.
Anyway, just finished it. Loved it. Want to do another playthrough, but will let the memory of up through Act 1 fade first.