If you got infected with the novel coronavirus and recovered, your blood could save lives.
Maybe.
Operating on a strong hunch, a growing number of hospitals is drawing “convalescent” blood plasma from recovered COVID-19 patients and injecting it into the bloodstreams of people with ongoing bad cases of the disease.
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The theory is that the antibodies from one person’s plasma might work against someone else’s load of the SARS-CoV-2 virus, hastening their recovery.
Convalescent plasma therapy is gaining popularity, thanks in large part to a centralized effort by the Mayo Clinic in Minnesota. Working with the U.S. Food and Drug Administration and the federal Biomedical Advanced Research and Development Authority, Mayo has developed rigorous standards for drawing and administering plasma.
More than 2,100 hospitals and clinics have signed up for Mayo’s COVID-19 Expanded Access Program. Nearly 4,800 physicians treating more than 10,000 patients are involved. As of Tuesday, around 6,000 patients have received infusions. There’s no published, peer-reviewed analysis yet on how those patients responded.
Mayo did not respond to a request for comment.
The upside of plasma therapy is that it’s available now. “Because this approach is simpler than developing an entirely new product, plasma can be used in clinical trials or under expanded access programs faster than new therapeutics or vaccines,” BARDA explained in a statement.
The downside of plasma therapy is that it’s largely untested and poorly understood. “COVID-19 convalescent plasma has not yet been demonstrated to provide clinical benefit in patients affected by this disease,” Mayo cautions on its website. “It’s not known if this treatment will or will not help those with COVID-19 or if it will have any harmful effects, but this is one of the only treatments that we have at present.”
There were signs as early as March that plasma therapy might work. Between late January and late March, a team of doctors at Shenzhen Third People’s Hospital in China administered convalescent plasma from five recovered donors to five critically ill COVID-19 patients.
The results were encouraging. Body temperature quickly normalized in four of the five patients. Viral loads decreased. The hospital soon discharged three of the patients. The other two were stable at the time of the trial’s publication in late March.
But the Shenzen doctors warned against drawing firm conclusions from an experiment involving only five patients. “This was a small case series that included no controls,” they wrote. “It is unclear if these patients would have improved without transfusion of convalescent plasma.”
Mayo built on the Chinese doctors’ work. The Expanded Access Program isn’t just treating patients—it’s also gathering data in an effort to confirm that convalescent plasma works. Months later, it’s still way too soon to say for sure.
Edwin Hayes, an infectious-disease doctor with the Prisma Health Hospital system in Columbia, South Carolina, is an investigator for the Mayo program. He told The Daily Beast he’s cautiously optimistic. “It’s too early to say confidently how well the plasma will work, but the mechanism makes sense, and we have used plasma for treating other viruses with varied success.”
One potential problem for the Mayo effort is that not all plasma is equal. And researchers still haven’t identified what might make one unit of plasma potentially more effective than another. “There is not consistent antibody testing or quantification of the plasma collected,” Hayes said.
If Mayo or some other institution proves that convalescent plasma therapy works—and that’s a big if—it might immediately face another big problem: supply. Demand for the therapy could skyrocket, easily outstripping the pool of willing donors. That gap could grow if, as many experts expect, there’s a second major wave of infections this summer.
“Plasma therapy is a limited resource that comes from donations,” Hayes explained. “The ability to distribute plasma is dictated by how many people come forward to donate.”
Mayo’s website explains how recovered COVID-19 patients can donate their plasma.
“People need to be aware that they have the ability to help,” Hayes said. “I think it’s an empowering opportunity that someone who has suffered through this might have the opportunity to shield someone else from that suffering, or even save a life.”
But in calling for donors, Hayes stressed he isn’t claiming plasma therapy definitely works. It’s promising. It’s also unproven.
“This could be a big turning point,” Hayes said, “but we need a lot more data.”
