A study of thousands of Covid-19 patients who received blood plasma transfusions from recovered patients indicates the experimental therapy appears to be safe, paving the way for future studies and clinical trials.
A team of researchers at Mayo Clinic, Michigan State University and Johns Hopkins University examined health outcomes of 5,000 hospitalized patients around the U.S. who received convalescent plasma treatment, and found the transfusions resulted in few serious side effects and there wasn’t an excessive mortality rate.
The study, posted Thursday on a public server called Medrxiv, hasn’t undergone peer review or publication in a scientific journal. Researchers found serious adverse events occurred in fewer than 1% of the treated patients, and the mortality rate seven days after transfusion was 14.9%.
“The mortality rate does not appear excessive,” the researchers concluded, given the lethal nature of the novel coronavirus and the fact that two-thirds of the patients in the study were critically ill in intensive care units when they received the transfusions. The patients got the convalescent plasma as part of an expanded-access, or “compassionate use,” program overseen by the U.S. Food and Drug Administration.
Researchers hope transfusions of antibody-rich plasma from recovered Covid-19 patients can help neutralize the coronavirus in patients who are sick. Investigators cautioned that it isn’t possible to determine from this study if the plasma was the cause of improved health outcomes, because every patient received the plasma. Proving that a drug works involves comparisons with a group of similar patients who don’t receive the experimental therapy.
The safety data is likely to bolster efforts to conduct more controlled clinical trials to test if convalescent plasma is an effective treatment for Covid-19, the investigators said. The findings also could reassure clinicians who want to give convalescent plasma to patients as a stopgap measure until vaccines or more targeted therapies are developed.
“The data are reassuring,” said Arturo Casadevall of Johns Hopkins University, one of the authors of the study. “Now we can focus on finding out if it is effective.”
A separate study, this one involving 25 patients with severe or life-threatening Covid-19 infections who received convalescent plasma transfusions, also was posted on the public server Wednesday. That study, at the Houston Methodist hospitals, found no adverse events associated with the therapy, and investigators indicated safety risks were comparable to what any seriously ill patient getting a transfusion would face.
The Houston study reported the death of one patient who received plasma, but investigators don’t believe it was related to the transfusion. The patient was severely ill, and the transfusion was a last-ditch lifesaving effort, said James Musser of Houston Methodist Hospital, the senior author on the study. “We feel comfortable giving additional patients the transfusions,” he said.
A concern about convalescent plasma therapy has been the potential for a serious side effect known as antibody-dependent enhancement, when transfused antibodies don’t neutralize a virus but rather make the infection worse. Investigators in both studies reported they observed no such effect in their convalescent plasma patients so far.
John Roback, director of Emory University School of Medicine’s Center for Transfusion and Cellular Therapy, who wasn’t involved in the large national study, said its safety findings are encouraging. But controlled clinical trials are needed to evaluate the 14.9% mortality rate, he said. “The number may be lower or no worse than these patients would be expected to experience as a group. But you don’t know until you do the trials.”
Still, the findings could encourage families of sick patients to request convalescent plasma. Programs now exist all over the country to collect convalescent plasma from recovered Covid-19 patients.
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Moises Batista, age 61, received convalescent plasma as part of the compassionate-use program and says he is convinced the transfusions helped him. He said he started feeling sick after a double shift at his job as a correction officer at Sing Sing Correctional Facility in Ossining, N.Y. He had a fever and lost his sense of taste and smell; he spent more than a week at home in New York City, taking Tylenol and resting, but nothing helped. “I felt horrible. I was trembling,” he said.
Mr. Batista’s 25-year-old son came to visit and was surprised to learn his father had not eaten in days. He called an ambulance. Mr. Batista was admitted to Mount Sinai Morningside “with obvious Covid,” according to John Puskas, chairman of cardiovascular surgery at Mount Sinai Morningside, who was on call the night Mr. Batista arrived.
Dr. Puskas said they treated Mr. Batista with medicine including steroids, antibiotics and high doses of oxygen. “All those things together did not keep him from deteriorating,” he said.
Mr. Batista didn’t immediately improve and spent a week in the intensive care unit. Nonetheless, Dr. Puskas said, after receiving the plasma, Mr. Batista “seemed convinced the minute he got it that he was going to do fine.”
Now at home, Mr. Batista says he feels much improved, though he still has to catch his breath when he walks. Thinking back on all the things the doctors did to save his life, Mr. Batista said, “I think the convalescent plasma made a difference. It came from a person who beat the disease. When they gave it to me, I felt it would help.”
Dr. Puskas said he can’t be sure how much Mr. Batista’s recovery was due to convalescent plasma versus “other therapies, his good attitude, his own immune response and other mechanisms independent of receiving another person’s plasma.”
“The short answer to those important questions is, we don’t know,” Dr. Puskas said.
Write to Amy Dockser Marcus at email@example.com
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