What is “Convalescent Plasma” and How Does It Treat COVID-19?
During the 1918 flu pandemic doctors found that giving blood from those who had recovered to those currently suffering from the flu could provide useful antibodies to help fight the infection. Since then, convalescent plasma treatment has been used in many infections, including severe flu, MERS, SARS and now with some success in SARS-CoV-2.
On August 23rd the FDA granted emergency use authorization (EUA) for convalescent plasma to treat COVID-19 patients. The decision should provide more patients in hospitals around the country with access to receive this treatment. Prior to the EUA issuance, doctors could use the therapy only if their patients were enrolled in a clinical trial studying the treatment, if they applied for special investigational use of the therapy (for very sick patients), or if their hospital was one of the approximately 2,800 participating in the expanded-use program through the National Convalescent Plasma Study.
While over 70,000 patients have received convalescent plasma treatment for COVID-19 infection to date, early data from smaller studies did not show significant improvement in those treated with it. More recent data from the National Convalescent Plasma Study is more promising and suggests early treatment (within 3 days of hospitalization) with plasma that has high concentrations of antibodies is associated with improved survival. One issue with the National Convalescent Plasma Study data, as pointed out by Francis Collins, Director of the NIH, and Anthony Fauci, Director of the NIAID, is that all of the participants were transfused with plasma from recovered patients, with no control group. Ongoing research is needed to make a clear assessment as to the safety and efficacy of convalescent plasma treatment.
If you have tested positive for COVID-19 and are interested in donating plasma, please see our article on this topic here for more information on local donation sites, including Stanford Blood Center.
Jennifer Abrams, MD, August 24, 2020