The reason I ask is that I was reading a statement by the Conference of the Parties to the World Health Organization Framework Convention on Tobacco Control. Basically what they are saying—and I've been hearing this from other experts in other meetings, as well—is that the only evidence they've found that actually says there's less harm is industry-sponsored research, and that there's been no definitive evidence to support this claim that these are less harmful.
On February 12th, 2018. See this statement in context.