As we continue to search for effective COVID-19 treatments, use of blood plasma from people who recovered from the virus seemed like a good thing. But on Friday morning, The New York Times reported that the Food and Drug Administration has put a hold on their emergency approval. The article also says that leaders at the National Institute of Allergy and Infectious Diseases, and even the famed Anthony Fauci, MD, voiced their skepticism of blood plasma as the life-saving treatment it was thought to be.
Experts expressed their concerns over the data generated thus far regarding plasma treatment. The Mayo Clinic released data on 35,322 people treated in a plasma trial. Although initial data showed some benefit to being treated with plasma within 3 days of infection, even that brought some concern. Three days is a very small window to get plasma to the patient and blood plasma cannot be manufactured, it must be donated from someone who recovered from a case of COVID-19 themselves.
Human blood is like a soup. When you strain out all the big pieces, what’s left is a rich broth. In blood, this broth is plasma and it was thought to contain possibly life-saving COVID-19 antibodies. After you get sick with certain viruses, your body keeps a memory of the illness to help fight it again. These memories are antibodies. The theory regarding blood plasma was that giving current patients some of the antibody soup from people who had recovered would allow the plasma to trick the body into fighting the virus.
There are also bigger issues regarding plasma treatment. Most of the plasma trials have no controls. In scientific experiments and medical trials, a control is an important part of proving your hypothesis, your idea. In the case of plasma trials, control groups would include some COVID-19 patients receiving plasma from someone who never had the disease. That would be the placebo. This would test if it was the plasma that made had the curing effect or the antibodies in the plasma. Due to the nature of the disease, The Times speculated that “… as many patients and their doctors — knowing they could get the treatment under the Mayo program — have been unwilling to risk receiving a placebo.”
This doesn’t mean that the plasma is no longer available, despite the FDA putting the emergency use authorization on hold. The authorization would have made using plasma easier, but doctors can still treat their patients with plasma if they can get it, as we wait for more data.