Use of Convalescent Plasma in the Management of COVID-19

The article, “COVID-19 Convalescent Plasma: From Donation to Treatment - A Systemic Review & Single Center Experience,” published in January/February 2021 issue of Missouri Medicine, discusses convalescent plasma (CP) as a treatment for COVID-19 infection, the limitations that could arise in recruiting donors, coordinating care, and delivering the therapy, particularly in the early phase of the pandemic. The use of CP in the U.S. was granted under the Expanded Access Program based on the assumption that plasma from recovered individuals could potentially contain antibodies to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, the antibody levels in the plasma units were unknown at the time of transfusion. Based on early analysis on efficacy and safety and lack of effective treatment, the Food and Drug Administration (FDA) supported the emergency use of COVID-19 CP.

Since then, studies have yielded mixed results. Clinical trials focusing on patients with COVID-19 who had moderate to severe illness failed to show significant clinical benefit. Observational studies showed that transfusion of CP to hospitalized COVID-19 patients with higher antibody levels and transfusion within three days yielded greater reductions in mortality. In subgroup analyses, the lower risk of death within 30 days of plasma transfusion in the high-antibody titer group was only seen among non-intubated patients before transfusion. However, these studies had significant limitations and potential biases and some were underpowered, making it difficult to conclude whether CP transfusion has any role in the treatment of patients with COVID-19.

On the other hand, serious adverse events after CP transfusion were not frequent and were similar to standard plasma transfusion. In the U.S., most common risks of plasma transfusion are non-infectious including transfusion reactions and allergic reactions.

Based on this available date and published literature, the National Institutes of Health COVID-19 treatment guidelines determined that “the data are insufficient to recommend for or against” the use of CP. The Infectious Diseases Society of America and American Association of Blood Banks recommended the use of CP to be limited to clinical trials stating that the benefit of CP will likely to occur in patients who are not critically ill and who received high antibody plasma unit titers within 72 hours of diagnosis or hospital admission.

Until more well conducted randomized controlled studies are completed, routine provision of CP for patients with COVID-19 should be discouraged. The administration of high-antibody titers CP should be limited to clinical trials, and those who have mild disease at high risk of progression early in the course of their illness.