The Evolution of Discourse in Online Communities Devoted to a Pandemic.

Online communities are increasingly important discursive spaces in which individuals obtain health information and engage in sensemaking, and they play an especially essential role during viral outbreaks in which social distancing requirements may preclude engagement with other communities and information sources. However, the manner in which those communities evolve in response to a rapidly developing public health crisis, as well as in reaction to one another, is not well-understood. This longitudinal study uses latent Dirichlet allocation to assess the co-evolution of three subreddits focused on COVID-19 during the earliest, most volatile stages of the outbreak. The results demonstrate the power of being the first online community addressing an emerging health crisis as well as the manner in which latecomers to the conversation gravitate toward distinct niches to differentiate themselves with respect to both topical foci and associated communication styles. The results also highlight individuals' detachment toward developments in even an unprecedented crisis such as a global pandemic, which represents a critical barrier that health communication professionals must overcome to persuade audiences to take health crises seriously. Future studies should examine the potential role of coordination among community administrators as well as the extent to which users are aware of and exert agency over the co-evolutionary processes spanning multiple communities.