COVID-19 Evidence Alerts
from McMaster PLUS^TM

In a randomized clinical trial of 86 hospitalized COVID-19 patients comparing standard care to treatment with 300mL convalescent plasma containing high titers of neutralizing SARS-CoV-2 antibodies, no overall clinical benefit was observed. Using a comprehensive translational approach, we unravel the virological and immunological responses following treatment to disentangle which COVID-19 patients may benefit and should be the focus of future studies. Convalescent plasma is safe, does not improve survival, has no effect on the disease course, nor does plasma enhance viral clearance in the respiratory tract, influence SARS-CoV-2 antibody development or serum proinflammatory cytokines levels. Here, we show that the vast majority of patients already had potent neutralizing SARS-CoV-2 antibodies at hospital admission and with comparable titers to carefully selected plasma donors. This resulted in the decision to terminate the trial prematurely. Treatment with convalescent plasma should be studied early in the disease course or at least preceding autologous humoral response development.

Infectious Disease rater

This well-documented article details the non-effect of convalescent plasma in the treatment of COVID-19 disease. It follows on the heels of the cessation of the NIH-sponsored Clinical Trial of COVID-19 Convalescent Plasma of Outpatients, whimsically named "C3PO". C3PO likewise showed no effect and was stopped. The current article suggests that most patients had neutralizing antibody already present at the time of the plasma infusion and further suggests that, if there is any use at all for convalescent plasma, it would be in patients who did not already have antibody. Convalescent plasma saw a burst of early enthusiasm in the pandemic when we otherwise had nothing. But these two carefully controlled studies emphasize the importance of meticulously designed research programs to inform clinical decision-making.