inclusion: - covid-19 positive on admission or during hospitalization (having been tested within the past 5 days) with symptoms consistent with covid-19 including fever (≥ 38c, 100.4f), pneumonia, symptoms of lower respiratory illness (e.g., cough, difficulty breathing), loss of smell or taste, myalgias, pharyngitis, or diarrhea - admitted to the regular medical floor or intensive care unit (icu) without severe ards (p/f ratio<100) - elevated d-dimer (>1.5g/ml) - age>18 years and not older than 90 - fibrinogen >100 - platelets >50,000 - no prior intracranial hemorrhage or recent ischemic stroke or tia within 6 months - d-dimer > 1500 ng/ml - no other clinical indication for therapeutic anticoagulation (e.g., deep vein thrombosis [dvt], pulmonary embolism [pe], atrial fibrillation, acute coronary syndromes, or extracorporeal membrane oxygenation) exclusion: - disseminated intravascular coagulation (dic) according to the international society on thrombosis and hemostasis overt dic definition - hemoglobin (hgb) <8 g/dl - hypersensitivity to heparin or heparin formulation including heparin-induced thrombocytopenia - thrombocytopenia: platelets<50,000 platelets/ul - uncontrolled or active/recent bleeding including intracranial hemorrhage, signs of active bleeding (e.g., blood transfusion within 30 days), any gi bleed within the past 6 months, or internal bleeding within the past 1 month - high bleeding risk: significant closed-head or facial trauma within 3 months, traumatic or prolonged cpr (>10min), or use of dual anti-platelet therapy - known or suspected pregnancy - recent (<48 hours) or planned spinal or epidural anesthesia or puncture - if the patient is on other anticoagulants, antihistamines, nonsteroidal anti-inflammatory drugs (i.e. aspirin) or hydroxychloroquine - uncontrolled hypertension

inclusion: - covid-19 positive on admission or during hospitalization (having been tested within the past 5 days) with symptoms consistent with covid-19 including fever (≥ 38c, 100.4f), pneumonia, symptoms of lower respiratory illness (e.g., cough, difficulty breathing), loss of smell or taste, myalgias, pharyngitis, or diarrhea - admitted to the regular medical floor or intensive care unit (icu) without severe ards (p/f ratio<100) - elevated d-dimer (>1.5g/ml) - age>18 years and not older than 90 - fibrinogen >100 - platelets >50,000 - no prior intracranial hemorrhage or recent ischemic stroke or tia within 6 months - d-dimer > 1500 ng/ml - no other clinical indication for therapeutic anticoagulation (e.g., deep vein thrombosis [dvt], pulmonary embolism [pe], atrial fibrillation, acute coronary syndromes, or extracorporeal membrane oxygenation) exclusion: - disseminated intravascular coagulation (dic) according to the international society on thrombosis and hemostasis overt dic definition - hemoglobin (hgb) <8 g/dl - hypersensitivity to heparin or heparin formulation including heparin-induced thrombocytopenia - thrombocytopenia: platelets<50,000 platelets/ul - uncontrolled or active/recent bleeding including intracranial hemorrhage, signs of active bleeding (e.g., blood transfusion within 30 days), any gi bleed within the past 6 months, or internal bleeding within the past 1 month - high bleeding risk: significant closed-head or facial trauma within 3 months, traumatic or prolonged cpr (>10min), or use of dual anti-platelet therapy - known or suspected pregnancy - recent (<48 hours) or planned spinal or epidural anesthesia or puncture - if the patient is on other anticoagulants, antihistamines, nonsteroidal anti-inflammatory drugs (i.e. aspirin) or hydroxychloroquine - uncontrolled hypertension