Vaping is just as harmful. It's just an excuse for them to market it and make more money.
National Center for Biotechnology Information: The FDA(part of US gov't) has reported that e-cigarette cartridges and solutions contain nitrosamines, diethylene glycol, and other contaminants potentially harmful to humans. They include nicotine, propylene glycol, glycerin, and tobacco flavoring. Propylene glycol, an FDA-approved solvent used in foods, a vehicle for intravenous diazepam, and as the major ingredient found in e-cigarette fluids, makes up about 90% of the solution. A small amount of diethylene glycol (approximately 1%), a known carcinogen and an ingredient in anti-freeze.. anit freeze yep. The stuff you put in your car is getting into the bloodstream. It also still contains nicotine. Just not as much as traditional cigs do. That was a quick summary from the only trusted source i could find.
More clinical trails and long term studies are needed before any confirmation can be made. But with the FDA already making a statement on it based off inital findings of how they are made up, it's not healthy. The US Court of Appeals has actually forbid companies from marketing them as a "better alternative" because they are not. But again more clinical trials are needed to further prove that case.