The reports suggesting a beneficial effect of nicotine on coronavirus disease 2019 (COVID-19) severity may encourage smoking. We aimed to analyze tweets on COVID-19 and smoking coming from casual Twitter users and Twitter accounts representing the tobacco industry. We collected tweets on COVID-19 and smoking from January 1 to May 1, 2020, using Twitter application programming interface. We analyzed sentiment, likes, or retweet to followers ratios, and the posts coming from the casual users to find pieces of news that could affect the discourse. Tweets coming from industry were analyzed manually. We analyzed n = 33,890 tweets on COVID-19 and smoking. The sentiment of tweets was negative, hitting a nadir in mid-March, but became less negative in April when preprints suggesting benefits from smoking on COVID-19 were released. Similar trends were observed for the ratios of likes or retweets to followers. We found 58 messages from the tobacco industry concerning COVID-19. Twenty-two (37.9 percent) mentioned the efforts of tobacco companies to support the development of a COVID-19 vaccine. Two tweets included Food and Drug Administration statements that there is no evidence that vaping increases the risk of COVID-19. The occurrence of preprints suggesting benefits of smoking in COVID-19 might increase sentiment and reactions to tweets on tobacco products and the virus. The authors of potentially controversial articles should restrain from the promotion of their results before the completion of the peer-review process. Twitter presents a convenient tool to monitor e-discourse during a health crisis. The research community should monitor the tobacco industry's social media.
Keywords: COVID-19; Twitter; coronavirus; smoking; social networking; tobacco industry.