Social media and the spread of misinformation: infectious and a threat to public health.

Misinformation has been identified as a major threat to society and public health. Social media significantly contributes to the spread of misinformation and has a global reach. Health misinformation has a range of adverse outcomes, including influencing individuals' decisions (e.g. choosing not to vaccinate), and the erosion of trust in authoritative institutions. There are many interrelated causes of the misinformation problem, including the ability of non-experts to rapidly post information, the influence of bots and social media algorithms. Equally, the global nature of social media, limited commitment for action from social media giants, and rapid technological advancements hamper progress for improving information quality and accuracy in this setting. In short, it is a problem that requires a constellation of synergistic actions aimed at social media users, content creators, companies, and governments. A public health approach to social media-based misinformation that includes tertiary, secondary, and primary prevention may help address immediate impacts, long-term consequences, and root causes of misinformation. Tertiary prevention to 'treat' this problem involves increased monitoring, misinformation debunking, and warning labels on social media posts that are at a high risk of containing misinformation. Secondary prevention strategies include nudging interventions (e.g. prompts about preventing misinformation that appear when sharing content) and education to build media and information literacy. Finally, there is an urgent need for primary prevention, including systems-level changes to address key mechanisms of misinformation and international law to regulate the social media industry. Anything less means misinformation-and its societal consequences-will continue to spread.