Early convalescent plasma treatment reduced COVID-19 progression in older adults

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Early administration of high-titer convalescent plasma against SARS-CoV-2, the virus that causes the novel coronavirus (COVID-19) to mildly ill infected older adults reduced the progression of COVID-19, according to a new study published in the in the New England Journal of Medicine.

For the study, researchers conducted a randomized, double-blind, placebo-controlled trial of convalescent plasma with high IgG titers against SARS-CoV-2 in older adult patients within 72 hours after the onset of mild COVID-19 symptoms. The primary end point was severe respiratory disease, defined as a respiratory rate of 30 breaths per minute or more, an oxygen saturation of less than 93 percent while the patient was breathing ambient air, or both.

A total of 160 patients underwent randomization. In the intention-to-treat population, severe respiratory disease developed in 16 percent of patients who received convalescent plasma and 31 percent who received placebo, with a relative risk reduction of 48 percent, the study said. A modified intention-to-treat analysis that excluded six patients who had a primary end-point event before infusion of convalescent plasma or placebo showed a larger effect size. No solicited adverse events were observed, the researchers said.

The trial was stopped early at 76 percent of its projected sample size because cases of COVID-19 in the trial region decreased considerably and steady enrollment of trial patients became virtually impossible, the researchers noted.

Evidence for convalescent plasma treatment in COVID-19 has been mixed. While the U.S. Food and Drug Administration (FDA) issued emergency use authorization in August, agencies including the World Health Organization were quick to point out the lack of evidence. Some observational studies have shown promise, however more recent research has found no benefit. Experts say the treatment is tricky, as it must be administered soon after infection to be effective.

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