Please select the eligibility criteria that correspond to the clinical trial below.
Title: Reduced-dosed Rivaroxaban and Standard-dosed Rivaroxaban Versus ASA in the Long-term Prevention of Recurrent Symptomatic Venous Thromboembolism in Patients With Symptomatic Deep-vein Thrombosis and/or Pulmonary Embolism
Brief Summary: This is a multicenter, randomized, double-blind, event-driven, superiority study for efficacy.

Patients with confirmed symptomatic DVT (Deep Vein Thrombosis) or PE (Pulmonary embolism) who completed 6 or 12 months of treatment of anticoagulation are eligible for this trial


Options:
A: Inclusion Criteria:

1. Positive SARS-CoV-2 diagnostic (on pharyngeal swab of deep airways material)
2. Positive pressure ventilation (either non-invasive or invasive) from \> 24 hours
3. Invasive mechanical ventilation from \< 96 hours
4. P/F ratio \< 150
5. D-dimer level \> 6 x upper limit of local reference range
6. PCR \> 6 fold upper limit of local reference range

Exclusion Criteria:

1. Age \< 18 years
2. On-going treatment with anticoagulant drugs
3. Platelet count \<100.000/mmc
4. History of heparin-induced thrombocytopenia
5. Allergy to sodium enoxaparine or other LMWH, unfractionated heparin or metylprednisolone;
6. Active bleeding or on-going clinical condition deemed at high risk of bleeding contraindicating anticoagulant treatment
7. Recent (in the last 1 month prior to randomization) brain, spinal or ophthalmic surgery
8. Chronic assumption or oral corticosteroids
9. Pregnancy or breastfeeding or positive pregnancy test. In childbearing age women, before inclusion, a pregnancy test will be performed if not available;
10. Clinical decision to withhold life-sustaining treatment or "too sick to benefit";
11. Presence of other severe diseases impairing life expectancy (e.g. patients are not expected to survive 28 days given their pre-existing medical condition);
12. Lack or withdrawal of informed consent.
B: Inclusion Criteria:

* Patients with a diagnosis of COVID-19 infection confirmed by polymerase chain reaction test (RQ-PCR) requiring hospital care for the administration of supplemental oxygen

Exclusion Criteria:

* Patients with life expectancy less than 48hrs
* Patients who require ventilatory support upon admission
* Age over 75 years or with a history of atrial fibrillation
* History of venous or arterial thrombosis
* Severe neurological impairment
* Absence of a primary caregiver to supervise the administration of medication
* History of cerebral hemorrhage
* History of previous use of oral anticoagulants
* History of major surgery 30 days prior to admission
* Uncontrolled systemic arterial hypertension
* KDIGO stage III chronic kidney disease or less
* Hemodialysis or peritoneal dialysis treatment
* History of active or inactive cancer
* Pregnant or postpartum patients
C: Inclusion Criteria:

1. Birth to \<18 years of age; AND
2. Positive nucleic acid test for SARS-CoV-2 within the past 7 days; AND
3. Hospitalized, \<72 hours post-admission; AND
4. One or more signs and/or symptoms of COVID-19 illness within the past 72 hours, as follows:

   1. Cough; OR
   2. Fever (oral temperature \>100.4°F/38°C); OR
   3. Chest pain; OR
   4. Shortness of breath; OR
   5. Myalgia; OR
   6. Acute unexplained loss of smell or taste; OR
   7. New/increased supplemental oxygen requirement; OR
   8. Acute respiratory failure requiring non-invasive or invasive ventilation; OR
   9. Encephalitis.

Exclusion Criteria:

An individual who meets any of the following criteria will be excluded from participation in this study:

1. Receiving therapeutic anticoagulation for treatment of a thromboembolic event diagnosed within the past 12 weeks; OR
2. Clinical-relevant bleeding (see criteria under Primary Outcome, below) within the past 72 hours; OR
3. Platelet count \<50,000/µL within the past 24 hours; OR
4. Prothrombin time (PT) ≥2 seconds above the upper limit of age-appropriate local reference range within the past 24 hours; OR
5. Activated partial thromboplastin time (aPTT) ≥4 seconds above the upper limit of age-appropriate local reference range within the past 24 hours; OR
6. Fibrinogen level \<75 mg/dL; OR
7. Severe renal impairment, as defined by estimated glomerular filtration rate (eGFR) \<31 mL/min/ 1.73 m2, as calculated by the Schwartz formula; OR
8. Parent or legally authorized representative unwilling to provide informed consent for patient participation.
D: Inclusion Criteria:

* Patients with confirmed symptomatic PE and/or DVT who have been treated for 6 to 12 months and did not interrupt anticoagulation for longer than 1 week

Exclusion Criteria:

* Legal lower age limitations (country specific) Indication for therapeutic-dosed anticoagulants Indication for antiplatelet therapy or a conventional non-steroid anti-inflammatory drug (NSAID) Hepatic disease which is associated with coagulopathy leading to a clinically relevant bleeding risk Calculated creatinine clearance \< 30 mL/min

Answer: D