I'm guessing that if this really is associated with vaping then it's likely due to the limited regulation of the ingredients. Bad batch of VG/PG/nicotine? Some problematic flavouring? I think the best article I've found is at the BMJ: https://www.bmj.com/content/366/bmj.l5228 - sorry, paywall. Very much inconslusive at the moment completely in the public health triage stage. Good idea to regulate it properly. I just…
I really enjoyed vaping, probably more than smoking, but somehow it did not seem to have the same addictive effect on me as smoking had. I did not find it that hard to stop cold turkey.