A multi-center international trial studying the immunoregulatory and regenerative potential of MRG-001 in severe and critically ill COVID-19 patients has been initiated by MedRegen. During this phase 2a study, 40 patients will be randomized to placebo or MRG-001 treatment. After 40 patients have been included, an interim-analysis will take place to assess the safety, tolerability and for the purpose of sample-size reestimation.