Convalescent Plasma and Placebo for the Treatment of COVID-19 Severe Pneumonia

Introduction The use of convalescent plasma in the treatment of infectious diseases has been empirically performed for more than a century. It is based upon the assumption that providing exogenous neutralizing antibodies may provide protection while affected patients mount their own immune response. This therapeutic approach appears of particular interest in the context of the current pandemic, in which there is no specific vaccine available nor adequately proven effective pharmacological treatments. Study purpose, hypothesis and general design Purpose of the study: evaluate the effectiveness and safety of convalescent plasma in the treatment of SARS-CoV-2 pneumonia (Covid-19) Hypothesis: Convalescent plasma significantly improves the clinical outcome in patients with Covid-19 pneumonia and severity criteria. Multicenter randomized, double-blind, placebo.controlled clinical trial. Placebo will be a saline solution. 3\. Methodological sustain for including a control arm with placebo Quality evidence about the effectiveness of convalescent plasma in the treatment of Covid-19 pneumonia is not yet available. Although case series and anecdotal reports appear encouraging, the implementation of its use in routine clinical practice requires the validation through controlled clinical trials. In addition the collection, administration and control of plasma is technically demanding and needs a clear support before broadly recommending it. Different scientific institutions and international organisms had clearly suggested to prioritize the application of novel therapeutic techniques with yet unproven efficacy within the context of clinical studies over its empirical use. On the other hand, for the present study, intervention strategy is proposed in "add-on" modality over the antiviral treatment that each participant may be already receiving, since they represent completely different therapeutic approaches. As such, participation in the present study will not condition the possibility of the participants to receive other treatments, either in intervention or control arms. 4\. Study objectives Primary objective Analyze the difference between arms on an ordinal score of six mutually exclusive categories at day 30 after study initiation. This score includes the following categories