Twitter is failing to rein in “superspreaders” of coronavirus misinformation on its platform, according to research detailing dozens of posts shared by high-profile accounts apparently flouting the social media group’s rules.

Tech companies including Twitter, Facebook and YouTube have all introduced new policies to clamp down on the so-called infodemic of false coronavirus information that has swept the internet in recent weeks amid panic and national lockdowns.

But a report from NewsGuard, which monitors and rates news websites on trustworthiness, found multiple posts from accounts on Twitter with 100,000 or more followers—some of which are verified—promoting misinformation about questionable treatments or cures that appear to violate recent policies banning such content.