The primary objective of the study is to determine if Prolastin plus SMT can reduce the proportion of subjects dying or requiring intensive care unit (ICU) admission on or before Day 15 or who are dependent on invasive mechanical ventilation on Day 15 versus SMT alone in hospitalized subjects with Coronavirus disease 2019 (COVID-19).

Inclusion Criteria:

1. Hospitalized male or female subject ≥ 18 years of age at the time of Screening who is being treated for COVID-19. Subjects must be screened within 48 hours (≤ 48 hours) of hospital admission.

2. Has laboratory-confirmed novel coronavirus (SARS-CoV-2) infection as determined by qualitative Polymerase Chain Reaction (PCR) (reverse transcriptase [RT]-PCR) or other commercial or public health assay in any specimen during the current hospital admission prior to randomization.

3. COVID-19 illness (symptoms) of any duration, including both of the following:

   1. Radiographic infiltrates by imaging (chest X-Ray, computerized tomography (CT) scan, etc.) and/or clinical assessment (evidence of rales/crackles on the exam) with peripheral oxygen saturation by pulse oximetry (SpO2) <94% on room air
   2. Any One of the following related to COVID-19: i. Ferritin > 400 nanogram per milliliter (ng/mL), ii. Lactate dehydrogenase (LDH) > 300 units per liter (U/L), iii. D-Dimers > reference range, or iv. C-reactive protein (CRP) > 40 milligram per liter (mg/L)

4. Subjects provides informed consent prior to the initiation of any study procedures.

Exclusion Criteria:

1. Subjects requiring invasive mechanical ventilation or ICU admission or with PaO2/FIO2 ≤ 150 mm Hg (ie, arterial oxygen in mm Hg divided by fraction inspired oxygen concentration [eg, 0.21 for room air]).
2. Clinical evidence of any significant acute or chronic disease that, in the opinion of the investigator, may place the subject at undue medical risk.
3. The subjects have had a known serious anaphylactic reaction to blood, any blood-derived or plasma product, or known selective immunoglobulin A (IgA) deficiency with anti-IgA antibodies.
4. A medical condition in which the infusion of additional fluid is contraindicated.
5. Shock that is unresponsive to fluid challenge and/or multiple vasopressors and accompanied by multiorgan failure considered not able to be reversed by the Principal Investigator.
6. Known alpha-1 antitrypsin deficiency for which the subject is already receiving alpha1-proteinase inhibitor augmentation therapy.
7. Women who are pregnant or breastfeeding. Female subjects of child-bearing potential must have a negative test for pregnancy blood or urine human chorionic gonadotropin (HCG)-based assay at Screening/Baseline Visit.
8. Subjects for whom there is limitation of therapeutic effort such as "Do not resuscitate" status.
9. Currently participating in another interventional clinical trial with investigational medical product or device.
10. Subjects previously requiring long-term oxygen therapy (home oxygen therapy).