I used to smoke a pack a day, and when I switched to vaping I personally felt much better. I was able to do things a bit better than when I was smoking cancer sticks.
Looking back I was lying to myself thinking it was just as good as quitting. I didn't feel the heavy tar on my lungs like cigarettes. I still noticed when pushing myself on work outs or hiking or biking or anything requiring aerobic activity that I would get sick to my stomach and almost puke like when you run long distance and are not used to it. I could go further than when I smoked but I would always hit this "wall" where I would get sick.
Quit 100% 3 months ago and took up XC Skiing. I could only do 2 miles when I first started. Just last week I did 10 miles and I have been going once on the weekend every week so in 12 sessions I was able to 5x my aerobic ability.
Starting at 0%, switching to vaping I would say made me feel/perform overall 15-20% better compared to cigarettes.
Quitting vaping filled in that other 80% and the difference is like night and day and so obvious I was lying to myself to keep the habit alive longer than I needed to.
Smoking timeline:
Smoked 18-30, transitioned to vaping.
30-31 vaped 12mg juice.
31-32 vaped 6mg juice.
32-33 vaped 3mg juice.
33-34 vaped 0 mg juice.
Quit Vaping 100% last Thanksgiving cold turkey (really was just mental habit at this point smoking 0 mg juice) 3 months vape free!
Our baseline should be the harm caused by nicotine by itself, propylene glycol, and food-safe flavors: nicotine causes addiction, which can definitely be considered a harm, but isn't itself associated with other negative health outcomes. Propylene glycol and flavors are generally regarded as safe.
Then, of course, we should extensively study the subject, since the lungs are a new route of administration† and vaping has become popular.
But it's important to correctly set the baseline. Associating vaping and smoking because they're behaviorally similar is superstitious behavior.
† Not new for proylene glycol, which is used in fog machines.
It's the overlap in user groups that connects them, especially considering they are more frequently (though not always) mutually exclusive and one is positioned, in the market and as lobbying of public policy, as a safer alternative than the other.
So, yes, scientifically it's important to understand the baseline risks of vaping independently of traditional smoking. But the outcome of that scientific research has to be used to inform policy decisions, and so from that perspective you have to compare those two baselines to each other.
Think of it like research on new medications: Showing the efficacy of your new medication over placebo is necessary but not sufficient. Part of the process entails a discussion on how your new medication compares to existing medications targeted at the same/similar health issues.
Which, we're not really starting from the null hypothesis at this point, but let's pretend that we are.
Starting from no data, saying that there's no evidence that vaping is less harmful than cigarettes is no different from saying there's no evidence that vaping is less harmful than guavas.
There's no evidence. That's where the sentence needs to stop. Then you get evidence, and we can have an informed conversation.
However, in the face of having to form public health policy decisions in the time between right now and a decade+ down the road where real, long-term studies can be completed, we can only use and compare that available data. Though we should hew very close to specific facts and avoid words open to very wide interpretation like "safer". (it may be safer along a single vector, carcinogens, but much worse in others, so it's a misleading term) We would be more wise to stick to specific known evidence like:
--Nicotine levels are similar, so there is little or no difference in health issues related to nicotine ingestion, except in so far as evidence shows nicotine salts used in vaping may hit your system faster.
--There are fewer known carcinogens or lower levels of them in vaping, but the effects of novel chemicals are not known. Short term health benefits in switching to vaping have been observed but longer terms outcomes are completely unknown, and could be worse.
--Use Risk, as apposed to a more ambiguous "safety", and say that vaping is not a risk-free activity from a health perspective.
The above could probably still be better stated, but I think the point is clear enough. This is no different than any other scientific issue or area of research. You use available data to convey the current state of knowledge, possible implications, further areas of study, etc. And as more data arrives, you expand and revise. But we're not starting from zero data.
A primary issue in this topic is that it is front & center in the media. Media in general is not good at conveying technical nuances, and the well-funded marketing arms of tobacco (and now vaping) companies have every reason to help the media make incorrect leaps of logic and over generalizations, e.g, fewer carcinogens == safer.
Another consideration is individual context: I'm trying to get my 67 year old father to switch from smoking to vaping because available evidence shows he will very likely be able to breath more easily, reduce his risk for heart disease, and so on. But he's 67: Long term risk from unknown vaping effects are probably a non issue for him, while he's about 4 years away from COPD. And there's zero chance of getting him to quit while I'd peg my chances around 1 in 10 of getting him to vape instead. If it were a friend my own age, I would have a different message, such as "You may very well be trading some short-term health for long-term issues that are as bad, or worse. Or maybe not, but we don't know, so quitting is the proper response, not switching to vaping"
We don't disagree on this, as I indicated, we're not starting from a null hypothesis here. It's a useful abstraction for the sake of argument.
All available evidence suggests that vaping is dramatically less harmful than cigarettes. There is a large enough population, who have been vaping long enough, that we should have some evidence to the contrary by now, if any was to be forthcoming.
Cigarette smoke, in addition to dozens of known carcinogens, contains small particle and carbon monoxide. Both of which are known to be terrible for your health, both of which are completely absent in vaping.
If I were trying to convince a young person not to vape, I'd stress that nicotine addition is a pointless and expensive mental slavery that is best avoided. Unless I knew they had ADHD or schizophrenia, in which case I'd leave them alone, since other people's medication is none of my business.
Stressing unknown harms that haven't been observed and probably won't be is a bad argument. They would be right to ignore it.
We have to measure and make decisions about unknown harms every day. We're not always good at it, but it's unavoidable. With respect to vaping, we know of very little in the way of foreign chemicals that can be safely inhaled. I think it's fair to say that available medical knowledge about inhaling chemicals points to a non-negligible chance that it might be bad for you. You seem to be saying we should mostly avoid reasoning about such uncertain risks. I'm saying it's not unreasonable to tell people, "we know inhaling many type of chemicals is harmful to your health, so there is potential for harm here as well. We'll know more in about a decade, and be fairly certain in 30 or 40 years."
Scientific rigor does not preclude reasoning about these risks before those 10 to 40 years are up.
It's been a few years since I've really looked at the research in depth but as I recall (smoking) tobacco was just a crazy outlier on the scale of what causes cancer. Part of the issue was the amount people smoked what seems absurd now where even someone who seems like they smoke a lot really only smokes a few a day. And compare that to cannabis consumption and the amount of organic material burned/inhaled per day is just astounding when you look at heavy tobacco smokers.
Also, as far as I've heard, the US's campaign against and problem with teenage vaping is unique and its treated completely differently in Europe/UK.
That's my strong intuition anyway. I don't have any skin in this game; I don't consume tobacco products in any form.
So someone just needs to blow some vape on a Geiger counter to test its radiation levels. I suspect the vape will be radiation free, as it doesn't need to contain the extra chemicals that lend tobacco its flavour.