Plasma, Once Out of Favor, Shows Promise Against Covid in Study

(Bloomberg) -- Newly infected Covid-19 patients saw a 54% decrease in the need for hospitalization after being given plasma from people who had recovered from the virus, according to a study by Johns Hopkins researchers that may offer hope for a new treatment option as variants threaten to reduce the effectiveness of other drugs.

The plasma needed to be given early and contain a high number of antibodies, the study’s authors cautioned. The study was posted to an online preprint service on Tuesday.

Researchers administered the convalescent plasma, which is derived from the blood of recovered patients, within nine days of the start of symptoms and compared a placebo plasma to one with a lot of antibodies, called “high-titer” plasma. 

Out of 589 patients in the placebo group, 37 were hospitalized, and out of 592 who received high-titer plasma, 17 were hospitalized, according to a preprint of the study posted on MediRxiv. Previous research has largely focused on hospitalized patients. Researchers transfused people in the study between June 2020 and October 2021 mostly with plasma from people who recovered from the original strain of Covid-19. 

Convalescent plasma has a beleaguered reputation since first being touted by former President Donald Trump who then pressured the U.S. Food and Drug Administration to give the treatment emergency authorization. The FDA did so in August 2020 but then narrowed its use in February to patients early in their hospitalization and rescinded its green light for low-titer plasma because research showed it didn’t work that well. 

A large, national study in the U.K. was stopped in January after researchers found no evidence convalescent plasma had an effect on hospitalized patients. 

Johns Hopkins researchers called on the FDA to extend the emergency authorization of plasma to patients with Covid-19 who weren’t in the hospital, particularly given the emergence of variants that may be resistant to certain antivirals and monoclonal antibodies. Monoclonal antibodies can also be hard to find at times. 

Researchers also noted the trial was able to include pregnant people, who are at high risk of Covid-19 complications but largely excluded from trials of other treatments, as plasma has been shown to be safe in studies. 

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