The purpose of the study is to determine if a high dose of Intravenous Immune Globulin (IVIG) plus Standard Medical Treatment (SMT) can reduce all-cause mortality versus SMT alone in hospitalized participants with COVID-19 requiring admission to the ICU through Day 29.

Percentage of Participants With Actual Intensive Care Unit (ICU) Discharge Time

description: Percentage of participants who were discharged from ICU were recorded. Time to actual ICU discharge was defined as duration of actual ICU stay from Day 1 through Day 29.
time_frame: Up to Day 29

Duration of Mechanical Ventilation

description: Duration (number of days) of ICU stay from post-randomization through Day 29 was calculated based on ICU admission and discharge (actual and medical equivalence) dates.
time_frame: Up to Day 29

Percentage of Participants With Actual Hospital Discharge Time

description: Percentage of participants who were discharged from the hospital were recorded. Time to hospital discharge was defined as duration of hospitalization from Day 1 through Day 29.
time_frame: Up to Day 29

Duration of Any Oxygen Use From Day 1 Through Day 29

description: Duration (number of days) of any oxygen use from Day 1 through Day 29 was calculated based on the start/stop dates.
time_frame: Up to Day 29

Mean Change From Baseline in Ordinal Scale

description: The ordinal scale is a 7-point scale ranging from 1 to 7 used to measure clinical status based on the following points: 1) Death; 2) Hospitalized, on invasive mechanical ventilation or extracorporeal membrane oxygenation (ECMO) 3) Hospitalized, on non-invasive ventilation or high flow oxygen devices; 4) Hospitalized, requiring supplemental oxygen; 5) Hospitalized, not requiring supplemental oxygen; 6) Not hospitalized, limitation on activities; 7) Not hospitalized, no limitations on activities. Higher score indicated no severe illness. Mean change in Ordinal scale was evaluated by fitting a linear mixed-effects model for repeated measures (MMRM). The data is reported for average across all postbaseline.
time_frame: Baseline up to Day 29

Absolute Change From Baseline in Ordinal Scale at Day 29

description: The ordinal scale is a 7-point scale ranging from 1 to 7 used to measure clinical status based on the following points: 1) Death; 2) Hospitalized, on invasive mechanical ventilation or extracorporeal membrane oxygenation (ECMO) 3) Hospitalized, on non-invasive ventilation or high flow oxygen devices; 4) Hospitalized, requiring supplemental oxygen; 5) Hospitalized, not requiring supplemental oxygen; 6) Not hospitalized, limitation on activities; 7) Not hospitalized, no limitations on activities. Higher score indicated no severe illness.
time_frame: Baseline, Day 29

Percentage of Participants in Each Severity Category of the 7-Point Ordinal Scale

description: The ordinal scale is a 7-point scale ranging from 1 to 7 used to measure clinical status based on the following points: 1) Death; 2) Hospitalized, on invasive mechanical ventilation or extracorporeal membrane oxygenation (ECMO) 3) Hospitalized, on non-invasive ventilation or high flow oxygen devices; 4) Hospitalized, requiring supplemental oxygen; 5) Hospitalized, not requiring supplemental oxygen; 6) Not hospitalized, limitation on activities; 7) Not hospitalized, no limitations on activities.
time_frame: Days 15 and 29

Percentage of Participants Who Develop Acute Respiratory Distress Syndrome (ARDS)

description: Acute Respiratory Distress Syndrome was defined based on Berlin criteria (chest imaging, origin of edema, oxygenation).
time_frame: Days 1, 5, 15 and 29

Percentage of Participants Who Develop ARDS Distributed by Severity

description: ARDS was defined by Berlin's criteria as: 1) Timing is usually within 1 week of a known clinical insult or new or worsening respiratory symptoms 2) Chest imaging: bilateral opacities-not fully explained by effusions, lobar/lung collapse, or nodules 3) Respiratory failure not fully explained by cardiac failure or fluid overload Need objective assessment (eg, echocardiography) to exclude hydrostatic edema if no risk factor present 4) Oxygenation: Mild 200 mm Hg < partial pressure of oxygen/fraction of inspired oxygen (PaO2/FiO2) ≤ 300 mm Hg with positive end-expiratory pressure (PEEP) or continuous positive airway pressure (CPAP) ≥ 5 cm H2Oc; Moderate 100 mm Hg < PaO2/FIO2 ≤ 200 mm Hg with PEEP ≥ 5 cm H2O; Severe PaO2/FIO2 ≤100 mm Hg with PEEP ≥ 5 cm H2O.
time_frame: Days 1, 5, 15 and 29

Change From Baseline in Sequential Organ Failure Assessment (SOFA) Score at Day 5, Day 15, and Day 29

description: SOFA score is a mortality prediction score that is based on the degree of dysfunction of six organ systems. The score is calculated on admission and every 24 hours until discharge using the worst parameters measured during the prior 24 hours SOFA score ranges from 0 (no organ dysfunction) to 24 (highest possible score / organ dysfunction). Higher score indicated severe illness.
time_frame: Days 5, 15, and 29

Change From Baseline in National Early Warning Score (NEWS)

description: NEWS is clinical scoring developed to improve detection of deterioration in ill participant. It is based on 7 clinical parameters: respiration rate, oxygen saturation, supplemental oxygen, systolic blood pressure (BP), pulse rate, level of consciousness, and temperature. A score of 0 and 2 was allocated to supplemental oxygen, 0 and 3 for level of consciousness and score of 0, 1, 2 and 3 for remaining parameters (i.e. respiration rate, oxygen saturation, systolic BP, pulse rate and temperature) where 0 = normal health condition to 3 = worst health condition; higher score indicated more severity. All scores were summed to get an aggregate score. Aggregate NEWS score ranged from 0 to 20, with higher scores meaning more severity/higher risk.
time_frame: Baseline and Day 29

Percentage of Participants Achieving Clinical Response: NEWS ≤ 2 Maintained for 24 Hours

description: Percentage of participants who achieved clinical response (i.e the NEWS score ≤2 maintained for 24 hours from Day 1 through Day 29) was estimated using the Kaplan-Meier method.
time_frame: Day 29 ^[1]