Can social media monitoring help identify the next EVALI? An examination of Reddit posts about vitamin E acetate and Dank Vapes

Background: Scientists identified vitamin E acetate (VEA) and "Dank Vapes" (a fake brand of tetrahydrocan-nabinol [THC] vaping products) as contributors to the 2019-2020 outbreak of e-cigarette, or vaping, product use-associated lung injury (EVALI). On social media, people who post about vaping or THC discussed the causes of EVALI. We examined whether Reddit conversations may have served as early signals of the outbreak. Methods: We collected Reddit posts from March 2018 to February 2020 on vaping-and THC-related subreddits that mentioned VEA or Dank Vapes. We identified peaks in post volume, examined post content, and used natural language processing to identify terms most characteristic of posts. Results: There were almost no posts about VEA before EVALI. Subsequently, there were two peaks, both refer-encing media coverage of scientific findings that linked VEA to EVALI. Discussion regularly referenced concerns about the legitimacy of Dank Vapes before EVALI; peaks in posts were largely unrelated to scientific findings or media coverage of those findings. The terms most characteristic of VEA posts were EVALI-related; those most characteristic of Dank Vapes posts were about quality or legitimacy. Conclusions: Although posts about VEA and Dank Vapes did not predict the outbreak, the public health com-munity could use social media to encourage people who vape or use THC to report future health concerns (e.g., through FDA's Safety Reporting Portal). Researchers and regulators could also use social media to see if potentially problematic products, such as Dank Vapes, have a history of concern among individuals who use those products.