Efficacy and Safety of COVID-19 Convalescent Plasma

Inclusion Criteria Blood donors: 1. Age: \>18 and \<60 years 2. Body weight : \>55 kg 3. Confirmed previous SARS CoV-2 infection 4. Minimum 28 days after the last symptom or finishing of the isolation, or 5. 21 day without symptoms from the date of the negative SARS CoV-2 test 6. Written informed consent to participate in this clinical trial, to donate plasma and to store the specimen for future testing. 7. Concentration of COVID-19 IgG antibodies more than 5 AU/ml (Because measurement of neutralizing antibody titers is not available now, storing of retention sample from the convalescent plasma donation is performed for determining antibody titers at a later date) 8. Male donors, or female donors who have not been pregnant, or female donors who have been pregnant tested negative for HLA antibodies 9. Individuals who meet all regular voluntary donor eligibility requirements Patients/recipients: 1. Age: \>18 years 2. Admitted to an acute care facility for the treatment of COVID-19 complications 3. Patients with severe or immediately life-threatening COVID-19, or 4. Patients who are judged by a healthcare provider to be at high risk of progression to severe or life-threatening disease. 5. Informed consent provided by the patient or healthcare proxy Exclusion Criteria: Blood donors: 1. Age : \<18 or \>60 years 2. Female subjects who are pregnant 3. HIV1,2 hepatitis B,C or syphilis infection 4. Donors ineligible for regular voluntary blood donation Patients/recipients: 1. Age : \<18 years 2. Contraindication to transfusion (severe volume overload, history of anaphylaxis to blood products) 3. Patients who received in the past 30 days immunoglobulin therapy 4. Females who are pregnant or breastfeeding