Study to Assess the Effect of Meplazumab on COVID-19

Inclusion Criteria: * Adults (≥18 years) with laboratory-confirmed SARS CoV 2 infection as determined by PCR or other commercial or public health assay, which is FDA cleared or approved for emergency use (test results must be obtained within 72 hours of Day * A score of Grade 3 (hospitalized, requiring supplemental oxygen) or Grade 4 (hospitalized, on non-invasive ventilation or high flow oxygen devices) on the 6-point ordinal scale. * Willingness and ability to comply with study-related procedures and assessments. * Ability to provide informed consent signed by study subject or legally authorized representative. * Male and/or female a)Male subjects: * A male subject must agree to use contraception as detailed in Appendix 12.3 of this protocol during the treatment period and for at least 6 months, corresponding to time needed to eliminate study treatment for both genotoxic and teratogenic study treatments, after the last dose of study treatment. b)Female subjects: * A female subject is eligible to participate if she is not pregnant (see Appendix 12.3), not planning to get pregnant in the next 6 months, not breastfeeding, and at least 1 of the following conditions applies: i) Not a woman of childbearing potential (WOCBP) as defined in Appendix 12.3. OR ii) A WOCBP who agrees to follow the contraceptive guidance in Appendix 12.3 during the treatment period and for at least 130 days, (5 terminal half lives and, for genotoxic products, an additional 30 days, corresponding to time needed to eliminate study treatment plus 30 days for study treatments with genotoxic potential) after the last dose of study treatment. Exclusion Criteria: * Any physical examination findings, laboratory abnormality, and/or history of any illness, that in the study Investigator's judgment, could jeopardize the safety of the subject by their participation in the study. * Subjects with evidence of critical COVID 19 illness, defined by at least 1 of the following: respiratory failure; shock (defined by systolic blood pressure \<90 mm Hg, or diastolic blood pressure \<60 mm Hg, or requiring vasopressors); or multi-organ dysfunction/failure. * Subjects requiring extracorporeal membrane oxygenation (ECMO). * Stage 4 severe chronic kidney disease or requiring dialysis (ie, estimated glomerular filtration rate(eGFR) mL/min/1.73 m2 \< 30). * Pregnant or breast feeding. * Anticipated transfer to another hospital which is not a study site within 72 hours. * Allergy to any study medication. * Use of anticancer, antitransplant rejection, or immunomodulatory biological drug or kinase inhibitor (eg, tocilizumab, sarilumab) or Janus kinase inhibitors (within 30 days of enrollment or 5 times the half-life \[whichever is longer\]). * Chronic glucocorticosteroid use equivalent to daily oral prednisone \>10 mg per day (10 mg oral prednisone every other day is allowed). * Live (live-attenuated) vaccines are not permitted within 2 weeks prior to randomization or during the study treatment and safety follow-up periods. * Subjects participating in another clinical study. There will be a need for washout with 5 half lives depending on the study treatment or 30 days since any previous study, whichever is longer. * Total bilirubin (TBL) \>2 × upper limit of normal (ULN), or alanine aminotransferase (ALT) \>5 × ULN, or aspartate aminotransferase (AST) \>5 × ULN, or alkaline phosphatase \>5 × ULN. * Platelet \<50×109/L, or hemoglobin \<60g/L. * Glomerular filtration rate \<30 milliliter(mL)/min/1.73 m2, or serum creatinine increased by 0.5 mg/dL within 7 days, or oliguria (\<400 mL/24 hour), or anuria (\<100 mL/24 hour). * Any physical examination findings, laboratory abnormality, and/or history of any illness, that in the study Investigator's judgment, could jeopardize the safety of the subject by their participation in the study.