Table 1. Characteristics of the included studies.

Study/Country	Participants	Interventions	Outcome
REMAP-CAP Investigators et al. 17 /United Kingdom	350 adults’ participants (age 61.4) hospitalized with moderate, severe, or critical pneumonia (O2 > 3 L/minutes, WHO Clinical Progression Scale [WHO-CPS] score ≥ 5 due to COVID-19	Standard care (glucocorticoids) plus single dose TCZ (8 mg/kg − up to 800 mg) versus Standard Care alone	All-cause mortality Time point: 21 days
Hermine et al. 7 /France	131 adults’ patients (age 64.0) hospitalized with moderate-to-severe COVID-19 pneumonia	Standard care (no information) plus single dose TCZ (8 mg/kg − up to 800 mg) versus Standard Care alone	All-cause mortality Need of mechanical ventilation Time point: 4 and 14 days
Tone et al. 14 /United States	243 adults’ patients (age 59.8) with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, hyperinflammatory states, and at least two of the following signs: fever (body temperature > 38 °C), pulmonary infiltrates, or the need for supplemental oxygen in order to maintain an oxygen saturation greater than 92%	Standard Care (no information) plus single dose TCZ (8 mg/kg − up to 800 mg) versus- Standard care alone	All-cause mortality Need of mechanical ventilation Time point: 28 days
Salama et al. 18 /United States	389 adults’ participants (age 55.9) hospitalized with COVID-19 with blood oxygen saturation below 94% while breathing ambient air	Standard care (antivirals; glucocorticoids - methylprednisolone, supportive care) plus one or two doses of TCZ (8 mg/kg − up to 800 mg) versus Standard Care plus placebo	All-cause mortality Need of mechanical ventilation Time point: 28 and 60 days
Veiga et al. 15 /Brazil	129 adults’ participants (age 60) with confirmed covid-19 who were receiving supplemental oxygen or mechanical ventilation and had abnormal levels of at least two serum biomarkers (C reactive protein, D dimer, lactate dehydrogenase, or ferritin)	Standard Care (no information) plus single dose TCZ (8 mg/kg − up to 800 mg) versus Standard care alone	All-cause mortality Need of mechanical ventilation Time point: 14 and 30 days
Rosas et al. 19 /United States	438 adult participants (age 60.9) hospitalized with Severe COVID-19	Standard Care (antivirals; low-dose glucocorticoids, convalescent plasma) plus single dose TCZ (8mg/kg − up to 800 mg versus Standard care alone	All-cause mortality Need of mechanical ventilation Time point: 28 and 60 days
RECOVERY Collaborative Group 16 / United Kingdom	Patients hospitalized (age 63.3) with COVID-19 with hypoxia (oxygen saturation < 92% on air or requiring oxygen therapy) and evidence of systemic inflammation (C-reactive protein [CRP] ≥ 75 mg/L)	Standard care (no information) plus single dose TCZ (8 mg/kg − up to 800 mg) versus Standard Care alone	Need of mechanical ventilation Time point: 28 and 180 days
Salvarani et al. 22 /Italy	123 adult participants (age 60) hospitalized with COVID-19 Pneumonia, with a partial pressure of arterial oxygen to fraction of inspired oxygen (PaO2/FIO2) ratio between 200 and 300 mm/Hg, an inflammatory phenotype defined by a temperature greater than 38 °C during the last 2 days, and/or serum CRP levels of 10 mg/dL or greater and/or CRP level increased to at least twice	Standard Care (no information) plus single dose TCZ (8 mg/kg − up to 800 mg) versus Standard care alone	Need of mechanical ventilation Time point:14 days