recipient inclusion criteria: - patients with severe covid-19 will be considered for randomization and will be transfused convalescent plasma within 3 days of symptom onset (severe covid-19) severe covid -19 defined by who interim guidance and the guideline of diagnosis and treatment of covid-19 of national health commission of china (version 5.0) along with confirmation by real-time rt-pcr assay with severe disease i.e. meeting any 2 of the following criteria- - patients on ventilator (in last 24 hours) - respiratory distress, rr ≥30 beats/min - oxygen saturation level less than 90 % in resting state - partial pressure of oxygen (pao2)/oxygen concentration (fio2) ≤ 300 mmhg - lung infiltrates > 50% within 24 to 48 hours recipient

recipient inclusion criteria: - patients with severe covid-19 will be considered for randomization and will be transfused convalescent plasma within 3 days of symptom onset (severe covid-19) severe covid -19 defined by who interim guidance and the guideline of diagnosis and treatment of covid-19 of national health commission of china (version 5.0) along with confirmation by real-time rt-pcr assay with severe disease i.e. meeting any 2 of the following criteria- - patients on ventilator (in last 24 hours) - respiratory distress, rr ≥30 beats/min - oxygen saturation level less than 90 % in resting state - partial pressure of oxygen (pao2)/oxygen concentration (fio2) ≤ 300 mmhg - lung infiltrates > 50% within 24 to 48 hours recipient