This is a research study to see how safe and effective decidual stromal cells are in treating patients with respiratory failure (breathing problem where not enough oxygen is passed from the lungs into the blood) caused by COVID-19.

COVID-19 viral infectious disease that has lead to high numbers of critically ill patients or death due to respiratory failure.

Decidual Stromal Cells (DSC) may be useful in the treatment of acute respiratory distress syndrome (ARDS) by reducing lung inflammation and then time that patients require help with breathing (mechanical ventilation).

Inclusion Criteria:

• Able to provide informed consent for participation in the study, either by the participant themselves or by the legally acceptable representative (LAR)
• Virological diagnosis of SARS-CoV-2 infection (PCR)
• Acute respiratory distress syndrome (ARDS) not due to cardiac causes
• Receiving mechanical ventilation

Exclusion Criteria:

• Severe comorbidity with life expectancy <3 months according to investigators assessment
• Currently receiving extracorporeal membrane oxygenation (ECMO)
• Patients with established positive bacterial blood cultures prior to enrollment or suspicion of superimposed bacterial pneumonia
• Patients with diagnosed significant pulmonary embolism or deep vein thrombosis in the previous 3 months
• Patients who have been intubated for more than 48 hours
• Known hypersensitivity to dimethyl sulfoxide (DMSO) or to porcine or bovine proteins
• Acute co-morbidity within 7 days before inclusion such as stroke
• History of severe chronic history of heart disease, recent myocardial infarction or unstable angina, lung disease (requiring home oxygen), pulmonary hypertension, or liver comorbidities
• Malignancy that requires treatment in the previous two years (excluding non-melanoma skin malignancies treated by excision, or cryotherapy)
• History of immunosuppression (immunomodulators or anti-rejection drugs in past year, or active disease, autoimmune disease on treatment, transplant recipients) or anaphylaxis
• Refusal of blood products
• Severe co-morbidity/co-morbidities which in the opinion of the investigators would compromise safety assessments
• Pregnant or breast-feeding
• Actively participating on another trial of an investigational agent for ARDS
• Unacceptable laboratory blood tests for alanine aminotransferase (ALT)/aspartate aminotransferase (AST), neutrophils, or platelets