Phase I / II multicentre, randomized and controlled clinical trial to evaluate the efficacy of treatment with hyperimmune plasma obtained from convalescent antibodies of COVID-19 infection.

Inclusion Criteria:

1. Informed consent prior to performing procedures. the oral consent be accepted testified to prevent paper handling.

2. Patient of both sexes, and ≥18 years.

3. SARS-CoV-2 infection determined by PCR in a sample of naso-oropharyngeal exudate or other respiratory specimen or determination of specific positive IgM antibodies, in <72 hours before randomization.

4. Patients requiring hospitalization for pneumonia COVID-19 without need until randomization of mechanical ventilation (invasive or non-invasive), and at least one of the following:

   • O2 saturation ≤ 94% in ambient air, or PaO2 / FiO2 ≤ 300 mm Hg.
   • Age> 65 years.
   • Presence of: high blood pressure, chronic heart failure, chronic obstructive pulmonary disease, liver cirrhosis, or other chronic pulmonary and cardiovascular diseases, diabetes, or obesity

Exclusion Criteria:

1. Requirement before randomization of mechanical ventilation (invasive or non-invasive).
2. Any of the following analytical data before randomization: IL-6> 80 pg / mL, D-dimer> 10 times ULN, ferritin> 1000ng / mL.
3. Participation in another clinical trial or experimental treatment for COVID-19.
4. In the opinion of the clinical team, progression to death or mechanical ventilation is highly probable within 24 hours, regardless of treatment provision.
5. Incompatibility or allergy to the administration of human plasma.
6. Severe chronic kidney disease grade 4 or requiring dialysis (ie eGFR <30)
7. Pregnant, lactating, or fertile women who are not using an effective method of contraception. It is considered a woman of childbearing age all women from 18 years and up to a year after the last menstrual period in the case of menopausal women