Application and Research of Mesenchymal Stem Cells in Alleviating Severe Development of COVID-19 Infection

This study is to evaluate the safety and efficacy of umbilical cord mesenchymal stem cells Therapy for COVID-19.

Since 2019, novel coronavirus Disease 2019 (COVID-19) has spread and prevailed all over the world. COVID-19 has a wide range of clinical manifestations of respiratory and non-respiratory symptoms, including mild or severe influenza-like syndrome, respiratory distress or respiratory failure, and may end in multiple organ failure. Mesenchymal stem cells (MSCS) are considered as ideal seed cells for the treatment of various diseases due to their unique immune regulation, self-renewal and multiple differentiation potentials. The safety of MSC transplantation in the treatment of COVID-19 patients has been proved by a number of clinical studies, and has shown good clinical efficacy in shortening the course of the disease, alleviating lung damage, and reducing the level of inflammatory factors. However, previous clinical studies mainly focused on the efficacy of MSC transplantation in critically ill patients of COVID-19, ignoring the important role of cell transplantation in delaying or preventing COVID-19 's progress and preventing reinfection.COVID-19 has spread throughout the country and even the world, and the increase in severe and critical cases has caused a great impact on national medical and health resources. Stem cell transplantation offers new treatment ideas for COVID-19 patients. Since the role of cell transplantation in delaying or preventing the progression of light and medium novel coronavirus infection and preventing reinfection has not been clearly reported, this study intends to use MSC transplantation to evaluate the role of stem cells in the occurrence and development of novel coronavirus infection, so as to provide an important reference for the prevention and treatment of COVID-19 by MSC.

Eligibility Criteria:
Inclusion Criteria:

* Age 18-85 years;The diagnosis of COVID-19 infection was clinically classified as Moderate cases, and the criteria were based on Diagnosis and Treatment Protocol for Novel Coronavirus Pneumonia(Trial Version 10)
* Having the relevant clinical manifestations of COVID-19 infection.
* Having one or more of the following etiological and serological examination results
* Tested positive for Novel Coronavirus nucleic acid
* Tested positive for Novel Coronavirus antigen
* Novel Coronavirus was isolated and cultured positive
* Novel Coronavirus specific immunoglobulin G reaches a titration of at least 4-fold increase during convalescence compared with the acute phase.
* Moderate cases diagnostic criteria：Persistent high fever \> 3 days or (and) cough, Tachypnea etc，but respiratory rate≧30 breaths/ min ,oxygen saturation \> 93% on finger pulse oximeter taken at rest. Radiology shows the characteristic manifestations of COVID-19 pneumonia
* There are one or more of the following risk factors for the development of severe / critical severity:
* Patients over 65 years old, especially those who have not been vaccinated against novel coronavirus
* Patients with cardiovascular and cerebrovascular diseases (including hypertension), chronic lung disease, diabetes, chronic liver and kidney disease, tumors and other underlying diseases, as well as maintenance dialysis
* Patients with immune deficiency (such as AIDS, long-term use of corticosteroids or other immunosuppressive drugs resulting in immune dysfunction)
* Patients with Obesity (body mass index ≥30)
* late trimester of pregnancy and perinatal women
* Heavy smoker.

Exclusion Criteria:

* Patients with prior or present tumor history,or precancerous lesions confirmed by pathological examination.
* Patients with active acute myocardial infarction or acute cerebral infarction.
* Pregnant or lactating patients.
* Patients with poorly controlled mental illness.
* Patients addicted to alcohol or drugs.
* Patients Unable or unwilling to sign informed consent or poor compliance.
* Patients with active tuberculosis or influenza virus, adenovirus and other acute respiratory virus infection.
* Patients deemed unsuitable for stem cell therapy by clinicians.
* Patients enrolled in other clinical trials within 3 months.