Title: Characterizing the most influential voices driving Twitter discourse about tobacco regulatory policy from September 2019 – July 2021 (Preprint)

BACKGROUND Twitter is an important avenue through which tobacco regulation evolves in the public consciousness. That said, prior research has identified the spread of mis and dis-information regarding tobacco products on Twitter and a possibly disproportionate influence of e-cigarette advocates on the platform taking an anti-regulatory stance. OBJECTIVE To examine the most influential users discussing tobacco regulation on Twitter. METHODS We used a keyword filter (F1 = .91) to identify N=3,159,807 tobacco-policy tweets by n=58,369 users from the full corpus of tobacco-related content between the vaping-associated lung injury outbreak starting in August 2019, continuing through the period before (period 1), during (period 2), and after pandemic stay-at-home orders (period 3), and through the months following vaccination rollout, up to July 2021. Top users by retweets and sustained influence (H index) were identified and coded. RESULTS Total posts and retweets received were heavily concentrated among the top 100 users at each of three time periods. The top 100 most retweeted users posted 8.5%, 21.4% and 34.6% of all original tweets during periods 1, 2 and 3, respectively and 56%, 48%, and 70% of all retweets. The 100 users with the top H index posted 8.3% of all content, 17.5%, and 27.3% with those posts accounting for 23.1%, 37.5%, and 16.9% of all retweets received during each period respectively. After coding user profiles, e-cigarette advocates comprised 44.5% (n=146) of top H index unique users across all three time periods. CONCLUSIONS While both the number of posts and number of users discussing tobacco policy on Twitter declined sharply with the onset of the COVID-19 pandemic, e-cigarette advocates continued to dominate both top 100 retweet and top 100 H index groups revealing the strong influence of anti-tobacco regulation advocates on Twitter.