Nothing absolute yet but the preliminary does not look good. From arsTechnica:
E-cigs shut down hundreds of immune system genes—regular cigs don’t
It’s widely assumed that swapping cigarette puffing for vapor huffing is better for health—after all, electronic cigarettes that heat up and atomize a liquid concoction can skip all the hazards of combustion and smoke. But researchers are still scrambling to understand the health effects of e-cig use (aka vaping) and to track down the variable and undisclosed components of those vaporized mixtures. The most recent data hints at unexpected health effects unique to e-cig use.
After comparing genetic information swabbed from the noses of smokers, vapers, and non-users of both, researchers found that smoking suppresses the activity of 53 genes involved in the immune system. Vaping also suppressed those 53 immune genes—along with 305 others. The results were presented Friday at the annual conference of the American Association for the Advancement of Science in Washington.
Though research on the significance of that gene suppression is still ongoing, the initial results suggest that e-cig users may have compromised immune responses, making them potentially more vulnerable to infections and diseases.
The abstract to the paper can be found here: New and Emerging Tobacco Products: Biomarkers of Exposure and Injury
More research is needed but still - a cautionairy tale...