I'm no doctor, but my guess is the vapor has the ability to temporarily stop the cilia from moving mucus, but nothing on the magnitude of tar and the 1000's of other chemicals found in smoke. As for empirical evidence, I vape exclusively (daily) and never have coughed up any oysters, never had a phlegm blob, no evidence of my lungs ability to move mucus whatsoever. I smoked for years, I know what damaged cilia feels like, and vaping shows none of the signs. When i used to smoke my pot, I'd still get the same issues as cigs. Smoke is smoke as far as your lungs are concerned.