Misinformation can be deadly. The Covid-19 pandemic has demonstrated that fact clearly and tragically. While the big tech companies have taken some steps to rein in misinformation and make credible organizations more visible, they lag far behind the pundits, scammers, and extremists who abuse trust on a global scale. It’s time for companies and researchers to take risks, make bold experiments, and rigorously test ways to slow the speed and spread of deadly deceptions.