Topic Diversity and Conspiracy Theories Shape Engagement with COVID-19 Misinformation on X/Twitter

The engagement with online health misinformation, particularly during COVID-19, poses unprecedented threats to societal well-being. The susceptibility to misinformation is heightened within a multi-topic context during health crises. This paper addresses a critical gap in understanding online engagement with multi-topic misinformation related to COVID-19. We conduct a comprehensive analysis of 7273 fact-checked source news claims related to COVID-19 and their corresponding social engagement on X/Twitter through the lens of topic diversity and conspiracy theories. Our analysis yields several key findings: (i) False news, especially when accompanied by conspiracy theories, exhibits higher topic diversity compared to true news. (ii) In terms of engagement from source claims to online posts, false news has a longer lifetime and receives more posts on X/Twitter compared to true news. Additionally, the integration of conspiracy theories is associated with a longer lifetime of COVID-19 misinformation. (iii) News posts characterized by heightened topic diversity receive increased social engagement on X/Twitter in terms of reposts, likes, and replies. However, the effect of topic diversity is moderated by the news veracity. High topic diversity is linked to more engagement with true news posts compared to false news posts. (iiii) The integration of conspiracy theories is linked to more social engagement with misinformation on X/Twitter. False news posts that contain conspiracy theories, on average, receive 40.8 replies compared to false news posts without conspiracy theories. These findings offer insights into understanding the engagement with multi-topic misinformation during health crises and highlight the importance of considering topic diversity and conspiracy theories in developing targeted interventions.