Uncertain Results in Convalescent Serum Study for Covid-19


A small study of patients who were seriously ill with the coronavirus suggests that treating the recovered patient with antibodies may aid recovery and survival, the scientists reported Friday.

The study, while far from conclusive, is said to be the largest of the subjects recovering from Covid-19, the disease caused by the coronavirus. Thirty-nine hospitalized patients received intravenous infusions of antibodies from patients who had recovered from the condition.

The course of disease in patients receiving convalescent plasma was compared to that of similar patients identified through electronic health records who did not receive treatment. This is a weak form of comparison, prone to error. And researchers are wary of studies being conducted at a single institution because the results are often not applicable to patients elsewhere.

Mortality rates were 12.8 percent among those who received the antibodies, compared to 24.4 percent among patients who did not receive this treatment.

The researchers provided percentages but not actual numbers of patients. And studies like these are fraught with difficulties.

The only way to know for sure if the treatment works is to randomly assign patients to receive antibodies or a placebo.

And it may be impossible to find many patients who agree to randomize their treatment to an unknown treatment, rejecting plasma treatment, Dr. noted. Arturo Casadevall of the Johns Hopkins School of Medicine in Baltimore.

The Food and Drug Administration has approved the use of convalescent serum in very sick patients. Few hospitalized patients may want to forgo a treatment that appears to be safe and could be effective.

"That train has left the station," said Dr. Casadevall.

Another idea, favored by researchers elsewhere, is a randomized trial to see if antibodies from recovered patients can prevent infections in healthcare workers who are at high risk for infection.

The goal is to have a multi-center trial, to avoid distortions that can arise when all data comes from a medical center. Investigators not associated with the study will assess efficacy.


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