Most of the articles I've read were hysteria-driven "OMG! Don't vape! It's dangerous and it'll kill you!!!" types. There were a few that reported "some" of these people vaped THC/CBD oils (added it in to the pod/tank themselves), and bought their liquid on the street. I'm very suspicious that the people who are suffering respiratory distress vaped something more than just normal e-liquid but aren't saying so because they could get into trouble from their parents and/or it's not legal where they live.
After over 7 years of vaping my doctor says my lungs sound extremely good, I don't run out of breath like I used to, and I think it would've done something negative before now.
Just my two cents.