In-Depth: Why hospitals abandoned convalescent plasma for COVID-19 patients

Plasma donation
Posted at 3:01 PM, Apr 29, 2021

SAN DIEGO (KGTV) -- For months, U.S. hospitals relied on convalescent plasma to treat severely ill COVID-19 patients, administering as many as 25,000 units per week.

But today, hospitals across the country have largely abandoned the once-touted therapy.

The news may come as a surprise to the hundreds of thousands of Americans who got the treatment, particularly those who credited the experimental therapy with saving their lives.

“The bottom line is that we have largely moved past convalescent plasma as a prevention strategy” for COVID-19, said Dr. Gary Firestein, senior associate vice chancellor for health sciences at UC San Diego.

Plasma is a mixture of immune cells and antibodies from the blood of someone who has recovered from a pathogen. Doctors have been using plasma to address various outbreaks since the early 1900s, from the 1918 flu to Ebola.

U.S. hospitals administered more than 700,000 units of plasma during the COVID-19 pandemic, based largely on lessons from previous outbreaks and early signals that it might be effective. Patients typically receive one or two units of the antibody-rich sera.

But new studies have revealed plasma offers no detectable benefit in severely ill COVID patients, leading many hospitals and regulators to restrict its use.

Scripps Health stopped using plasma at its five hospitals earlier this year. Many blood banks have stopped collecting it.

This month, the Infectious Diseases Society of America said it recommends not using plasma in hospitalized patients at all.

“After you're very sick and you have lots of lung inflammation, at that point it’s not so much the virus that's causing the problem, but your immune response to the virus that is causing the problem,” said Dr. Firestein.

Hospitals started using the first plasma infusions in March 2020, days after the World Health Organization declared a pandemic. So why did it take nearly a year and more than 700,000 infusions to figure out the stuff isn’t really working?

Dr. Firestein says early studies on plasma relied on “observational” evidence, meaning they weren’t scientifically rigorous trials with a control group.

He said the only way to truly test a therapy is to have a control that doesn’t get the therapy for comparison. And finding patients for a control group during the teeth of the pandemic proved challenging, particularly after the Food and Drug Administration gave doctors broader permission in August to administer plasma.

“There was an Emergency Use Authorization for convalescent plasma that made it essentially impossible then to do a randomized control trial,” he said.

“As soon as it became widely available for any physician to write an order and infuse convalescent plasma, it essentially eliminated the potential for studying it and finding an answer,” Dr. Firestein added.

Experts say plasma might still be useful during the early stages of an infection, but in recent months doctors have shifted to an alternative: lab-made monoclonal antibodies.

“You’re generating them under ideal pharmaceutical conditions and you can assure that there's sufficient quantities of antibodies and robustness of the antibodies,” said Dr. Thomas Buchholz, medical director of Scripps MD Anderson Cancer Center and a Scripps Clinic physician.

With convalescent plasma, different batches might vary in potency, depending on the immune response from the donor.

The San Diego Blood Bank said it is still accepting plasma donations, but just a fraction of what it once collected. In January 2021, the blood bank collected 1,203 units of plasma. In March 2021, it collected 58 units. The San Diego Blood Bank says it’s continuing to accept these donations as a kind of insurance policy: in case a bad variant escapes the vaccines.