Persuasive strategies in online health misinformation: a systematic review

A proliferation of a variety of health misinformation is present online, particularly during times of public health crisis. To combat online health misinformation, numerous studies have been conducted to taxonomize health misinformation or examine debunking strategies for various types of health misinformation. However, one of the root causes - strategies in such misinformation that may persuade the readers - is rarely studied. This systematic review aimed to fill this gap. We searched Web of Science, Scopus, PsycINFO, and Communication and Mass Media Complete for studies published between 2011 and 2021 on 29 May 2021. Peer-reviewed studies that discussed persuasive strategies in online misinformation messages were included. Of 1,700 articles identified, 58 were eligible and 258 persuasive strategies were extracted. Following the affinity diagraming process, 225 persuasive strategies in online health misinformation were categorized into 12 thematic groups, including: fabricating narrative with details, using anecdotes and personal experience as evidence, distrusting government or pharmaceutical companies, politicizing health issues, highlighting uncertainty and risk, inappropriate use of scientific evidence, rhetorical tricks, biased reasoning to make a conclusion, emotional appeals, distinctive linguistic features, and establishing legitimacy. Possible antecedents for why and how these persuasive strategies in online health misinformation may influence individuals were discussed. The findings suggest that media literacy education is essential for the public to combat health misinformation.