a blood bag partially full of yellow liquid
a blood bag partially full of yellow liquid

Convalescent Plasma for COVID-19 Cuts Hospitalizations: Preprint

Unlike studies of antibody-rich transfusions in hospitalized patients, which overall have not found clear benefits, a new randomized trial finds that early convalescent plasma treatment cuts hospitalizations in half.

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Shawna Williams

Shawna is a senior editor and news director for The Scientist.

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Dec 21, 2021

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Just two weeks ago, citing the results of multiple trials, the World Health Organization recommended against the use of plasma from people who’ve recovered from COVID-19 as a treatment for the disease. Now, based on a new study in patients treated relatively early in the course of their disease, a research team has asked the agency to reconsider its recommendation. According to the new results, posted today (December 21) in medRxiv and not yet peer reviewed, treating patients with what one coauthor calls “high-octane plasma” within eight days of the onset of COVID-19 symptoms resulted in a 54 percent reduction in hospitalizations compared with a control group. 

“We think this could be a useful tool in the toolbox for treating this very serious disease,” said coauthor Kelly Gebo, an infectious disease researcher at the Johns Hopkins University School of Medicine, in an online news conference about the results. 

See “NIH Halts Outpatient COVID-19 Convalescent Plasma Trial” 

The study, conducted between June 2020 and October 2021, included 1,181 patients, each of whom was randomly assigned to receive either what’s known as high-titer plasma—which had been verified to contain a high concentration of antibodies against COVID-19—or control plasma. The study took place at 24 sites around the US, and due to its timing, most participants were unvaccinated. The authors found that 6.3 percent of control-group participants and 2.9 percent of people who received the high-titer plasma required hospitalization for COVID-19 within 28 days of the treatment. 

In the news conference, the researchers suggested that one key to their promising results was treating patients early—in contrast to most studies on convalescent plasma for COVID-19, which have focused on hospitalized people and have generally found little evidence of benefits in disease progression or survival. The authors suggested that the WHO and the US Food and Drug Administration (FDA), which currently authorizes use of convalescent plasma for COVID-19 only for hospitalized patients, should change their policies based on the new results in order to allow the treatment to be used in outpatients during the current surge in infections.  

See “Indian Study Shows No Survival Benefit of Plasma in COVID-19

According to The Washington Post, a group of scientists has petitioned the FDA to authorize use of convalescent plasma in outpatients, based partly on the results of the trial. Liise-anne Pirofski, an immunology researcher at Albert Einstein College of Medicine who was not involved in the study but who signed the letter to the FDA, tells the newspaper that such an expansion is “critical” to combat Omicron—“a matter of national security.” However, infectious disease researcher Jeanne Marrazzo of the University of Alabama at Birmingham expresses caution about the results “in the wake of prior studies that have failed to show benefit. The practicalities of using it as widespread therapy are also daunting," she tells the Post.