Collective dynamics of health (mis)information contagion during the COVID-19 pandemic

Abstract Background The spread of health misinformation through social media has become a major public health problem. Although there is a broad consensus among health professionals, researchers and policy makers on the need to control health disinformation, there is still little evidence on the effects that misinformation contagion could have on public health strategies. The present study aims to characterize COVID-19 infodemic and its impact on social and health decision-making processes. Methods The present study follows a mixed methods approach combining survey data, social media mining techniques, and agent-based models (ABM) to analyze the processes of health misinformation diffusion from different simulated scenarios. Results The analysis of a massive dataset obtained from Twitter during the first months of the pandemic reveal a high politicization of health issues, which would result in clear divisions around fundamental issues for the control of the health crisis such as, for example, the need for vaccines or the follow-up of preventive measures. In addition, social bots were identified as a source of disinformation that favors the dissemination of false or misleading content, while contributing to increase social polarization (e.g., among extreme right-wing ideology and low-SES individuals). From the ABM, significant differences were detected in the impact of the relevance/centrality of the agents and the topology of the networks in relation to specific topics. Specifically, in relation to the topic of vaccines, high reciprocity was observed among members of the anti-vaccine community, which points to the difficulty of combating misinformation and carrying out health promotion interventions in this group. Conclusions Our findings show that the impact of health misinformation can vary considerably depending on the sources of misinformation, the topology of the network and the topics on which debates are articulated. Key messages • The spread of health misinformation on social media is a major public health issue, influencing social and health decisions, with little evidence on its long-term effects. • COVID-19 misinformation is highly politicized, with social bots amplifying polarization, especially among right-wing and low-SES individuals, making health interventions more challenging.