In an unusual move, the Food and Drug Administration today announced that is making it easier for doctors to try an experimental treatment for COVID-19 patients that uses plasma from people who had the disease and recovered.
There is scant evidence it works in people infected with the coronavirus, but the approach has been tried for other illnesses.
The idea is that this so-called convalescent plasma will contain antibodies to the virus that allowed the donor to recover to disease, and therefore should help patients who are sick.
Convalescent plasma been used in the past to treat outbreaks polio, measles, and mumps before a vaccine was available. More recently it's has been used with some effectiveness to treat patients with SARS and Ebola.
In guidance to doctors, the FDA stated, "Given the public health emergency that the expanding COVID-19 outbreak presents, while clinical trials are being conducted, FDA is facilitating access to COVID-19 convalescent plasma for use in patients with serious or immediately life-threatening COVID-19 infections."
Doctors will still have to get FDA approval for individual patients to use the treatment, but if doctors need an answer in less than four hours, they can call the FDA Office of Emergency Operations for a verbal authorization.
The idea for using convalescent serum to treat COVID-19 has been championed by Arturo Casadevall of the Johns Hopkins Bloomberg School of Public Health and Liise-anne Pirofski from the Albert Einstein College of Medicine.
Casadevall has been interested in the use of convalescent serum to treat outbreaks of viral diseases throughout his career. In February, he wrote an op-ed piece for The Wall Street Journal suggesting it be used in the current outbreak. He followed that up with a scientific paper and then started hearing from doctors all over the country asking if they could participate in a clinical trial of the approach.
Casadevall was hoping to hear from the FDA that it would give him approval to start a trial. The broader usage granted by FDA was a surprise.
"The FDA just opened the floodgates," wrote Jeffrey Henderson, associate Professor of Medicine and Molecular Microbiology at Washington University School of Medicine in St. Louis in an email to NPR. "Our institution is scrambling to be ready to use this, as are many others, I'm sure."
As with any unproven therapy, there are risks with the approach. The worst is that it could actually make patients sicker, a response known as antibody-dependent enhancement where the virus is actually helped to proliferate by a patient's own immune system.
"I think we need to be cautious about using convalescent serum," says Martin Zand, professor in the department of medicine and co-director of the Clinical & Translational Science Institute at the University of Rochester Medical Center.