They are being attacked on social media and by e-mail, telephone, letter and in person. And their reputations are being smeared with baseless accusations of misconduct. Sometimes, this escalates to real-world confrontations and attacks. Such threats to scientists aren’t new; those researching climate change and gun control, for example, have endured abuse for decades. However, since the start of the COVID-19 pandemic, there has been an unprecedented escalation in the intensity and frequency of attacks, and the range of targets, say researchers.