Reddit Discussions During the 2022 Mpox Outbreak: Observational Analysis of Sentiment, Topics, and Audience Engagement

Background: Public health crises often reshape online discourse by amplifying uncertainty, frustration, stigma, and misinformation, with important implications for risk communication. Objective: This study examines these dynamics on Reddit (Reddit Inc) during a recent outbreak, using Mpox as a case study. Methods: We analyzed sentiment, topical themes, and audience engagement in posts and comments drawn from 4 Mpox-related subreddits. Using natural language processing methods, we applied sentiment analysis and latent Dirichlet allocation to classify 1169 posts and 6571 comments (from July 21, 2021, to July 16, 2025) into sentiment categories and 9 distinct topics. Of the 1169 posts, 611 (52.3%) were neutral, 370 (31.6%) were negative, and 188 (16.1%) were positive. Among comments, 2825 of 6571 (43%) were neutral, 1962 (29.9%) were negative, and 1784 (27.1%) were positive. We then used Kruskal-Wallis tests, Dunn post hoc comparisons, and Vargha-Delaney A to assess relationships among sentiment, topic, and engagement metrics. Results: Engagement differed significantly by sentiment (P