In prespecified, intention-to-treat analyses, the PLACID Trial investigators found no net benefit associated with convalescent plasma in patients admitted to hospital with moderate covid-19. The composite primary outcome (progression to severe disease or all cause mortality at 28 days) occurred in 19% (44/235) of patients in the intervention arm and 18% (41/229) of patients in the control arm (risk ratio 1.04, 95% confidence interval 0.71 to 1.54). Restricting the comparison to the subset of patients who received plasma with detectable antibody titers did not change the outcome.4

Small beneficial effects were found for resolution of shortness of breath and fatigue. However, these results should be interpreted with caution, because the trial was not blinded, so knowledge of treatment status could have influenced the reporting of subjective symptoms by patients who survived to day 7.