Randomized clinical trial comparing convalescent plasma to best available therapy (BAT) for the treatment of severely ill and critically ill patient with COVID-19: Patients will be electronically randomized 2:1 (plasma vs BAT) in a double blind fashion. Patients with SARS-CoV-2 PCR confirmed infection with pulmonary infiltrates and hypoxemia will be screened and invited to participate. Primary outcomes will be early all-cause mortality, and secondary outcomes will include all cause in hospital mortality, length of mechanical ventilation and hospital stay, time to PAO2 \>200, progression of pulmonary infiltrates, antibody titers and time to negative PCR detection
