ABSTRACT
Convalescent plasma therapy was administered in patients with acute, viral respiratory disorders with severe clinical course (SARS- or MERS coronavirus, influenza H1N1, H5N1). These studies suggested that convalescent plasma is likely to improve viral clearance, reduce the length of hospital stay and reduce mortality and appeared to be safe. However, since controlled randomized trials were lacking only low-quality evidence was available. Most patients mount a strong humoral immune response early in the course of a SARS-CoV-2 infection, including neutralizing antibodies. Due to the pandemic an increasing number of convalescent patients who are potential donors for SARS-CoV-2 convalescent plasma will be available. We designed a prospective randomized clinical trial to study the safety and efficacy of convalescent plasma for treatment of severe COVID-19 and its mechanism of action (CAPSID trial). Here we present the rationale for this trial and major aspects of the study outline.