There appear three questions here; what are the harmful effects of (1) vaping, (2) inhaling nicotine vapour (3) inhaling flavourings vapour.
I agree the flavourings are the unknown, regardless of how ingested, chemicals of any kind are not great.
On pure nicotine in a vape, I have yet to find evidence of long term vaping harm.
Your article here does not change my view.
I have been doing for almost ten years now, and I still say the thirty five years I spent smoking before that did far more harm.
Now, and you can guess my age, I can run up many flights of stairs, run, cycle, swim at good pace indefinitely, do thirty press-ups per day etc, which I could not do before.
After describing the effects in very technical, scary sounding terms, we see the observation of the study are that the effects measured were temporary, recovering after one hour.
The effects of any form of exercise could probably be described in an even more scary way!
Exercise takes days to recover from!
The final conclusion of the study, in their own words says it all :-
“Further studies are needed to address the potentially adverse long-term effects on vascular health”.
In other words, nothing long term found.
Which brings us to questioning your confirmation bias. What do you have to gain from creating an impression vaping is harmful? Will you feel better if many people return to smoking after being scared by your article?
Does it make you feel better to think, or create a false impression that vaping in a person’s life might affect their health more than say, breathing in petroleum exhaust fumes every day, for life, like we all do whether we like it or not?
Would you dare compare the results of this study with the results of something like that?
No shortage of tests with proven long term conclusions there.