Convalescent Plasma Reduced COVID-19 Mortality by 10%

In a study published in The New England Journal of Medicine, clinicians and researchers show that passive immunization by administering plasma taken from convalescent donors after infection with the SARS-CoV-2 coronavirus to patients suffering from acute respiratory distress syndrome requiring artificial mechanical ventilation significantly reduced mortality by 10%.

The effect on reducing mortality was more specifically observed in patients who received convalescent plasma during the first 48 hours after being put on artificial respiratory assistance.

The randomized phase 2 clinical trial involved 17 intensive care units in Belgian hospitals. It included a total of 475 patients from October 2020 to March 2022. 

Thanks to the collaboration of the Belgian Red Cross and the laboratories of the KULeuven, UAntwerpen, and ULiège, the intensive care units of the study's partner hospitals were able to use convalescent plasma with high neutralizing antibody titres of 1/320 for 82.3% of patients and 1/160 for the remaining 17.7%.

"For the first time, we have demonstrated the therapeutic value of convalescent plasma in improving these patients' very poor vital prognosis. The reduction in mortality, of the order of 10%, is particularly noticeable in patients who were given convalescent plasma rapidly after the start of artificial respiratory ventilation", explains Dr. Benoît Misset, head of the intensive care unit at the CHU of Liège and Assistant Professor at the Faculty of Medicine at the University of Liège, who is responsible for and first author of this study.

"This study documents and confirms the value of convalescent plasma for passive immunization, but also against possible pathogenic variants and possibly in the event of future pandemics," wrote these researchers on October 25, 2023.