(HealthDay)—Early in the COVID-19 pandemic, anecdotal reports suggested that infusing very sick patients with the blood plasma of people who’d survived the disease might help boost outcomes.

But study findings released Nov. 24 in the New England Journal of Medicine, along with disappointing results from prior trials, suggest that those initial hopes may have been unfounded.

The new study was conducted by researchers in Argentina. It compared outcomes for 228 hospitalized COVID-19 patients who got an infusion of so-called “convalescent plasma” against those of 105 patients who did not (the “placebo group“). All were so sick as to have developed pneumonia.

However, one month later, “no significant difference was noted between the convalescent plasma group and the placebo group” in terms of clinical outcomes, with about 11% of patients dying in both groups, according to a team led by Dr. V.A. Simonovich of the Italian Hospital of Buenos Aires.

The theory behind the use of survivors’ blood plasma in people battling COVID-19 is that plasma contains immune system agents that might aid recipients in their fight against the disease.

But a prior study from India—this time in patients with “moderate” COVID-19—also found little benefit of the treatment in stopping illness from progressing to a more severe stage. That study was led by Dr. Anup Agarwal, of the Indian Council of Medical Research in New Delhi, and was published Oct. 22 in the BMJ.

According to one U.S. expert unconnected to either trial, it may be time to give up on convalescent plasma as a viable COVID-19 treatment.

“There have been several major trials that have shown the same results: Convalescent plasma does not seem to have an impact on the course of COVID-19,” said Dr. Mangala Narasimhan. She’s senior vice president and director of Critical Care Services at Northwell Health, in New Hyde Park, N.Y.

Narasimhan also noted that in the Argentinian trial, “even with good measurement of the amount of antibody they were giving people [in the transfusions], there was no benefit seen.”

She believes that other treatments should remain first-line options for severe COVID-19.

“The new monoclonal antibodies will give a more targeted and reliable antibody load to COVID-19 patients and may have an impact on the course of disease if given early after positive testing,” Narasimhan said.

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