Merriam-Webster’s word of the year for 2021 was vaccine, but it could just as easily have been ‘misinformation’. This nebulous thing has been front and centre since the dawn of the pandemic.Stemming the flow of misinformation has proved difficult, for governments and particularly for social media companies. Do you try to repress it, stop it from spreading – adopt a mitigation approach, as it were? Do you go for an elimination approach, deleting misinformation, pretending it never existed? Do you try to educate people to get better at spotting it – a time-intensive process which might not even yield results?

All these questions and more are the focus of a new report from the United Kingdom’s Royal Society. Frank Kelly is a Professor of the Mathematics of Systems at the Statistical Laboratory, University of Cambridge, and Chair of the report.