The Wall Street Journal reports there are now 1,604 cases of the vaping-related illnesses, according to the Centers for Disease Control and Prevention (CDC). Federal officials are still looking for the definitive cause of the illnesses but have flagged illicit THC products and oils as a major factor. Recent unpublished data from researchers at Boston Children’s Hospital supports that, showing that videos about “do it yourself” vaping cartridges and fake THC cartridges took off on YouTube in the months before public-health officials started reporting the injuries. Boston Children’s Chief Innovation Officer, John Brownstein, PhD, and Yulin Hswen, PhD, are both interviewed for the article. Read more from The Wall Street Journal.