I will add that this study looked at biological markers of inflammation and so on with cells exposed to vape vapor. If you are looking at it and saying "looks like there is activity, so maybe there is harm, more likely than not" but not saying anything about how much harm then it is not very useful for making choices. Sure, it is not without some risk, but a quantified risk assessment would say that based on the current best evidence it is likely not anywhere near as bad as smoking and it is easier to taper nicotine out if you want to do that.

From a public health/harm reduction perspective vapes may be a useful tool if used correctly, or a terrible additional harm with increased addictiveness and known dangerous chemicals, such as the popcorn lung issues. We need rational science and appropriate regulation, not panic and bizarre policies.