Antithrombotic Therapy to Ameliorate Complications of COVID-19 (ATTACC)

This is a prospective, open-label, multicentre, Bayesian adaptive randomized clinical trial to establish whether therapeutic-dose parenteral anticoagulation improves outcomes for patients hospitalized with COVID-19 (e.g., reduces intubation or mortality). Participants will be randomized either to the investigational arm (therapeutic anticoagulation with heparin for 14 days or until "recovery" \[defined as hospital discharge or liberation from supplemental oxygen if initially required\], whichever comes first), or to the control arm (usual care, including thromboprophylactic dose anticoagulation according to local practice).