What is the role of convalescent plasma in the treatment of COVID-19?

Updated: Jan 12, 2021
  • Author: Setu K Patolia, MD, MPH; Chief Editor: Zab Mosenifar, MD, FACP, FCCP  more...
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The use of plasma from individuals who have recovered from COVID-19 has the potential to provide passive immunity through the transfer antibodies. Preliminary data from the largest observational study by the Mayo Clinic showed that hospitalized patients who were transfused within 3 days of diagnosis of COVID-19 had significantly lower 7- and 28-day mortality rates compared with patients transfused 4 or more days after the diagnosis. [45] In addition, the study demonstrated that a higher titer of antibodies in plasma was associated with lower 7- and 30-day mortality. Three randomized controlled trials did not show any mortality benefit. The first randomized controlled trial by Li et al was stopped early. [46] Simonvich et al. also randomized 334 patients with severe COVID-19 pneumonia to receive either convalescent plasma or placebo. [47] Median time from the onset of symptoms to enrollment in the study was 7 days in this study. Therefore, it is harder to make any conclusion about mild-to-moderate COVID-19 patients or the benefit of plasma given very early in the course of the disease. The PLACID trial enrolled patients with moderate COVID-19 pneumonia and randomized them to receive either placebo or convalescent plasma. [48] Four-hundred sixty-four patients were enrolled in this study. Convalescent plasma did not reduce composite outcome of progression to severe disease or all-cause mortality at 28 days. However, the study was limited by an inability to measure the titer of antibodies in convalescent plasma. For hospitalized patients with COVID-19, IDSA guidelines recommend to use plasma only in the context of clinical trials. [35]

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