High-Dose Convalescent Plasma for Treatment of Severe COVID-19

C linical signs and symptoms of coronavirus disease (COVID-19) are pleomorphic, varying from none (asymptomatic) to life-threatening. Typical signs/ symptoms are fever, dry cough, dyspnea, fatigue, myalgia, anosmia, and ageusia (1). Radiography or computed tomography of the chest usually reveals bilateral pulmonary ground-glass opacifi cations, mainly in posterior and peripheral areas of the lungs (2). The most common laboratory test alterations are lymphopenia and elevated serum concentrations of infl ammatory biomarkers and D-dimers (3). Risk factors for unfavorable outcomes are older age, concurrent conditions, and perhaps but of lesser importance, blood type A (4,5). Thus far, there is no consensual agreement about specifi c therapy for this disease, despite several attempts to develop one (3,6). More recently, antiviral agents such as MK-4482/EIDD-2801 and PF-07321332 seem to be promising (7,8). In the past, passive antibody transfer by plasma or serum transfusion has been used clinically to treat other infectious diseases, including Ebola, infl uenza A, severe acute respiratory syndrome, and Middle East respiratory syndrome, as well as . The presence of antiviral antibodies, in patient serum or in COVID-19 convalescent plasma (CCP), has been associated with more favorable clinical outcomes (14). Thus, CCP seems to be an attractive therapy because it is a potential source of neutralizing antibodies (15, 16) . The fi rst case series reported from China suggested favorable outcomes for 5 patients receiving undergoing mechanical ventilation who received CCP on days 10-22 after hospital admission (17). Also in China, 10 critically ill patients received 200 mL of CCP with a neutralizing antibody titer of >640, which resulted in undetectable viral load and clinical improvement for 7 of the 10 patients (18). In a nonrandomized