Just chiming in with my own odd vape health related issue.
I've been happily vaping for about 9 years now, very happy I've quit smoking, and it's all thanks to vaping. I still vape, and do not currently have any health issues, just to be clear.
However, I can't vape anything with any kind of flavors whatsoever. The side effect is quite strange. If I vape any flavor, more so anything with fruit, I'm OK for a day or so, and then I begin to develop a severe burning in my abdomen. It's more than just heartburn - it is actually specifically where my gallbladder used to be, which would likely be the biliary duct that was cut when my gallbladder was removed.
When I first started vaping, and was not aware of this side effect for me, I spent a great deal of time in severe pain. At one point, I developed sepsis, and it was discovered that I had a biliary stricture, which caused bile to back up into my liver, and caused an infection. I was in the hospital for 10 days, IV antibiotics, and a procedure to drain the infection and put a stent in the biliary duct to keep it open.
I have been ok since, but if I take a few puffs of anything flavored, I feel the beginning of that pain again.
It might be dumb that I continue to vape after that, but I seem to have settled on a 100% VG NET juice that I can vape with no side effects. I've been on this for several years without issue.
While I want to support this miraculous invention that helped me quit, and I am revolted by the hysteria that politicians and media are latching onto, I would like to see these products made to be safe. I was discouraged that when I was going through that pain, I wrote to several vendors to ask about ingredients when I experienced a painful side effect. None of them shared an ounce of information with me. While we love and support our vendors, it is a bummer that they chose to ignore my concerns. I could have been killed.