When you lose attribute points due to sickness, are these points lost permanently, or do you regain points in time without using SA points?

I guess it would depend on the sickness; those who can be completely cured and those who affect your body for the rest of your life (leprosy or whatever).

I would say permanent. I dont think lesser diseases are serious enough to be reflected in the rules and the more serious ones will leave their mark (even if that mark is just the kind of muscle atrophy that I suppose anyone here who practise physical training and have had a 2 week flue recognizes).

More severe diseases may weaken the heart, lower the lung capacity or give you an autoimmune disease. Without our medical facilities even we would have far more of those complications in the west.