Everything We Know About Convalescent Plasma for COVID-19 Treatment

On August 23, the Food and Drug Administration (FDA) granted an emergency use authorization (EUA) for a novel COVID-19 treatment. Since then, more than 72,000 patients with the virus in the U.S. have been treated with convalescent plasma therapy. But convalescent plasma may not be the answer we were hoping for. 

First, the nature of convalescent plasma has its limitations when it comes to widespread administration. Unlike other typical new drugs, plasma cannot be manufactured in bulk—its availability is limited by blood donations from recovered COVID-19 patients. President Trump has urged these individuals to come forward in a nationwide campaign to collect plasma. 



But the therapy has other issues. Since the FDA issued an EUA, convalescent plasma has been shrouded in controversy. What do we know about its mechanisms, and why has the treatment been so controversial? 

Convalescent plasma (CP) therapy involves transfusing blood plasma from patients who have recovered from COVID-19 into the blood of patients who are currently suffering from an ongoing COVID-19 infection. The idea is to transfer defensive antibodies which are contained in the plasma. 



Before the plasma is transfused, it must be purified and tested for safety. Plasma is typically screened for HIV, hepatitis types B and C, as well as SARS-CoV-2. The treatment involves the injection of approximately 8 ounces of plasma over a 1- to 2-hour period. Additional transfusions may be administered if determined clinically necessary. 

Despite an EUA from the FDA, the National Institutes of Health (NIH) determined that there was no solid evidence for or against the treatment of COVID-19 patients with convalescent plasma. The NIH finding emerged less than ten days after the FDA granted temporary approval of the treatment. 

"There are currently no data from well-controlled, adequately powered randomized clinical trials that demonstrate the efficacy and safety of convalescent plasma for the treatment of COVID-19," the NIH announced online.

Despite reports from the President and top health officials of a 35% reduction in COVID-related deaths after treatment with convalescent plasma, this statistic appears to have been miscalculated based on a study by the Mayo Clinic which only includes a specific subset of patients: those who were under 80 years of age, had not been placed on ventilators, and received treatment within three days of diagnosis. 



Another study from China, published in the Journal of the American Medical Association, showed similar results to the Mayo Clinic study. Neither studies found a significant effect of convalescent plasma therapy on reducing death rates among COVID-19 patients. Instead, they suggested clinical improvement among a specific subgroup of patients.