Efficacy, Safety and Perspectives of Convalescent Plasma Therapy for Coronavirus Disease 2019

The coronavirus disease 2019 (COVID-19) pandemic, which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has resulted in over 38 million confirmed cases and over one million deaths worldwide. With few available effective treatments, convalescent plasma (CP) from recovered patients is an inexpensive alternative for COVID-19 treatment. The emergency use of CP for COVID-19 treatment has been authorized by regulatory agencies even while clinical trials are ongoing. Most of the completed clinical trials have included only a small number of patients and have not been randomized. Due to limitations in study design, it has been difficult to draw definitive conclusions on the effectiveness of CP therapy (CPT) for COVID-19. There are various factors that affect the outcomes of CPT, including disease severity of the plasma recipient, pathophysiological status of the recipient, timing of CP administration, and units of CP transfused. While recent evidence demonstrated that early transfusion of CP with high antibody titers leads to improved clinical outcomes and reduced mortality of hospitalized COVID-19 patients, many studies did not measure the antibody levels in the administered CP. As results from existing studies suggest that CPT could be a safe and effective therapy for hospitalized patients with COVID-19, routine measurement of CP antibody titers, along with patient stratification, will be critical in future clinical trials.

Keywords: Convalescent plasma therapy; Severe acute respiratory syndrome; Coronavirus 2; Coronavirus disease 2019; Neutralizing antibodies

Abbreviations: CP: Convalescent plasma; CPT: Convalescent plasma therapy; COVID-19: Coronavirus disease 2019; SARS-CoV-2: Coronavirus 2; FDA: Food and Drug Administration; EUA: Emergency use authorization; MERS: Middle eastern respiratory syndrome; SARS: Severe acute respiratory syndrome; nAbs: Neutralizing antibodies; IND: Investigational new drug; RBD: Receptor binding domain; ADE: Antibody-dependent enhancement; SAE: Serious adverse event; TACO: Transfusion-associated circulatory overload; TRALI: Transfusion-related acute lung injury; ELISA: Enzyme-linked immunosorbent assay