Opinion Leaders and Twitter: Metric Proposal and Psycholinguistic Analysis

Social media and personal health might be a dan-gerous combination: people are influenced by what they read online and don't pay attention to who wrote what they read. What happened during the COVID-19 pandemic? Who were the opinion leaders on social media? What were the conversations about? How did the health institutions communicate? To under-stand this, we focus on Twitter, and we analyze more than three million of Italian-written tweets posted from January 2020 to December 2021. We propose a method to identify opinion leaders and to analyze the content of the conversations. Results show that: (i) opinion leaders are linked to what they say and when they say it; (ii) politicians, newscast, and ordinary people accounts were able to become opinion leaders during the pandemic; (iii) conversations moved from a medical focus (at the beginning of the pandemic) to a social focus (in the last months of 2021); (iv) absence of health care institutions among opinion leaders. These results show that our approach might be useful for those who want to monitor the social scenario in terms of health (e.g., to identify as soon as possible accounts against or critical to medicine or to health authorities).