Diffusion of vaccine misinformation in a Taiwanese online community: The role of influencers and echo chambers (Preprint)

BACKGROUND Prevalence of and spread of misinformation are a concern for the exacerbation of vaccine hesitancy and a resulting reduction in vaccine intent. However, few studies have focused on how vaccine misinformation diffuses online, who is responsible for the diffusion, and the mechanisms by which that happens. In addition, researchers have rarely investigated this in non-western contexts particularly vulnerable to misinformation. OBJECTIVE This study aims to identify COVID-19 vaccine misinformation, map its diffusion, and identify the effect of echo chamber users on the misinformation diffusion on a Taiwanese online forum. METHODS The study uses data from a popular forum in Taiwan, PTT. A crawler scraped all threads on the most popular sub-forum from January 2021 until December 2022. Vaccine-related threads were identified through keyword searching (n = 5,818). Types of misinformation, including disinformation, conspiracy, propaganda, and fabricated content, were coded by two researchers. Polarity was proposed as a proxy for measuring individual’s level of involvement in echo chamber, one of the mechanisms responding for the viral misinformation on social media. Factors related to information diffusion, including misinformation type and polarity were then assessed with negative binomial regression. RESULTS Out of 5,818 threads, 3,830 (65.8%) were identified as true information threads, and 1,601 (27.5%) contained misinformation, yielding 5,431 boards for analysis. Misinformation content did not vary much from other contexts. Propaganda related information was most likely to be reposted (RR: 2.07, p < .001) when comparing to true information. However, the more polarized a user was, the less likely his/her content to be reposted (RR: 0.22, p < .001). By removing the nodes with high level of indegree, outdegree, and betweenness centrality, we found that the core network and the entire network demonstrated a decreasing trend in average polarity score, which showed that influential users contributed to the polarization in misinformation consumption. CONCLUSIONS While the forum exhibits a resilience to echo chambering, active users and brokers contribute significantly to the polarization of the community, particularly through propaganda-style misinformation. This popularity of propaganda-style misinformation may be linked to the political nature of the forum, where public opinion follows “elite cues” on issues, such as shown in the U.S. The work in this study corroborates this finding and contributes a data point in a non-western context. To manage the echo chambering of misinformation, more effort can be put into moderating these users to prevent polarization and spread of misinformation to prevent growing vaccine hesitancy. CLINICALTRIAL