Our friends over at e-Cigarette Reviewed published an interview with researcher Jean-Francois Etter about his recent study on the impact of long-term vaping. It's a good read all around, but keep in mind this is not what should be considered a conclusive study. Even so, it demonstrates some major potential with e-cigarettes.
No ex-smokers in your study who were vaping relapsed to daily smoking – why do you think the relapse rate is so low? Do e-cigs really seem to be that effective, or is it likely to be just a quirk of the sample selection process?
JFE: Both elements played a role here, But the effect is so large (normally 95% of ex-smokers relapse within one year) that it cannot be attributed only to selection problems, there must be a real effect here. E-cigs most probably prevent relapse in former smokers.
That's a huge deal in comparison to traditional NRT. Even if 50% of that can be attributed to sampling bias, that's still significantly better than anything else. It also seems to blow the whole gateway argument out of the water.