By Dr. Max Gomez

NEW YORK (CBSNewYork) — Early in the COVID-19 pandemic, there was a glimmer of hope for treating patients with something called convalescent plasma, which is taken from the blood of patients who recovered from the coronavirus.

The hope was that antibodies in that plasma could save newly-infected patients, but CBS2’s Dr. Max Gomez reports a new study says it doesn’t work.

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It was hopeful in the beginning when doctors had very little with which to treat COVID patients.

So when a small handful of patients recovered, the theory was that their plasma contained neutralizing antibodies that could be extracted and given to newly-infected patients.

For a while, it seemed to work. There were reports of COVID patients recovering after being given the so-called convalescent plasma.

Studies on the plasma were all over the place. Some apparently helped and others failed to benefit the patient.

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What may be the definitive randomized study on convalescent plasma has just been released in “Nature Medicine.”

“We stopped using convalescent plasma months and months ago. It just simply doesn’t work, and the trials really have failed to demonstrate any benefit,” said Dr. Thomas Balcezak, chief medical officer for Yale New Haven Health.

Not only does convalescent plasma not work, Dr. Balcezak said, the study suggests it could cause harm.

“I think this new trial that came out yesterday is probably the final nail in the coffin on convalescent plasma as a treatment, because it also suggests that there’s the real potential for harm, not just lack of benefit,” he said. “That’s really concerning.

The harm could come from all the other accumulated antibodies when you collect plasma from the donor. Those antibodies could react in the recipient, causing unintended side effects.

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It’s just unclear what the potential harm could be, while not conferring any benefit. That’s what doctors want to avoid.

Dr. Max Gomez