In just the past month, there’s been a rash of hospitalizations whose only common factor is vaping. At least one person has died. Given the great popularity of vaping with younger people, and its fairly recent explosive rise in use, the Centers for Disease Control and Prevention are already actively investigating the causes of these hospitalizations and whether even the discussion of risks below is understated. https://www.npr.org/sections/health-shots/2019/08/16/751823475/whats-behind-a-cluster-of-vaping-related-hospitalizations
Here’s a description of the apparent problem, as known so far: https://www.ecowatch.com/vaping-health-blood-vessels-2639938271.html?