Health misinformation and disinformation: Old narratives, new technologies.

This editorial discusses how health misinformation and disinformation combine long-established narratives with new technologies that substantially increase the speed, reach, personalization, and apparent credibility of misleading content. The novelty of the contemporary information environment lies less in entirely new false narratives than in digital infrastructures that allow misleading content to be created, tailored, disseminated, and monetized at unprecedented scale. Online social media platforms and generative artificial intelligence (AI) have transformed these conditions, enabling misleading health information to be created and disseminated at previously impossible scale and speed. Health misinformation and disinformation can influence behavior, undermine trust in scientific and public health institutions, delay appropriate care, promote ineffective or harmful interventions, and weaken responses to disease outbreaks. Their effects may be particularly pronounced among populations with limited access to reliable information, healthcare, and trusted institutions. This editorial also examines how engagement-driven platform design, commercial and political incentives, synthetic media, and inconsistent safeguards amplify the problem. It argues that fact-checking and individual media literacy, while necessary, are insufficient on their own. A more effective response requires timely, transparent public health communication; institutional support for healthcare professionals; greater platform accountability; systematic safety evaluation of generative AI; independent access to relevant data; and policies that address the incentives sustaining the production and circulation of false and misleading health information.