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WASHINGTON — The Food and Drug Administration on Sunday issued an emergency authorization for doctors to treat Covid-19 using blood plasma from patients who’ve recovered from the disease.

Below, STAT answers the major questions surrounding convalescent plasma as a Covid-19 treatment and the science supporting its use.

What is convalescent plasma, and how does it work?

When people get sick with Covid-19, their immune systems generate antibodies to fight the disease. Those antibody proteins float in their blood plasma — the liquid component of blood that suspends blood cells.   

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Doctors can harvest the plasma, test it for safety, and then purify it to isolate those antibodies. That “plasma-derived therapy,” or “convalescent plasma,” can be injected into another patient sick with Covid-19, and the antibodies it contains can help fight the virus early in an infection until the patient’s own immune system generates its own antibodies in sufficient quantities to beat back Covid-19.

Does scientific evidence show that convalescent plasma is a safe and effective treatment for Covid-19?

The Mayo Clinic released data in June that showed plasma treatment was safe following transfusion in a group of 20,000 patients, which included substantial enrollment from Black and Latino patients.

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A study released Aug. 13 — but not yet peer-reviewed — suggested that using convalescent plasma to treat patients with severe Covid-19 soon after their diagnosis was associated with a lower likelihood of death. But the study had serious scientific limitations that make interpreting the findings difficult.

The Mayo Clinic study, which enrolled more than 35,000 patients, showed that patients who received transfusions within three days of their Covid-19 diagnosis had a seven-day death rate of 8.7%, while patients who received plasma treatment after four or more days had a mortality rate of 11.9%. The difference met the standard for statistical significance.

The study didn’t include a placebo group for comparison, however, so it’s unclear exactly how impactful the plasma treatment might be. The study was sponsored by the National Institutes of Health and sought to broaden access to convalescent plasma, part of a so-called “expanded access” program not designed to definitively test how well the treatment works, but instead to quickly get it to patients.

More rigorous randomized, placebo-controlled studies of convalescent plasma are ongoing.

What does an emergency use authorization, or “EUA,” mean?

The FDA has issued a number of emergency authorizations for Covid-19 treatments: Most notably the Gilead Sciences antiviral remdesivir, and for the antimalarial drug hydroxychloroquine, which the agency has since withdrawn.

The authorizations mean, effectively, that the agency believes the treatments in question are promising and largely safe, though there’s not yet definitive data supporting their efficacy.

An EUA for convalescent plasma would effectively license doctors across the country to begin treating Covid-19 patients with convalescent plasma, but it’s unclear whether it will result in a meaningful expansion in access to the therapy, in part because the supply is limited by the number of recovered patients who donate plasma.

The Mayo Clinic study, which relied on an FDA “expanded access” program, was broad enough that it allowed 35,000 patients access to the treatment despite the lack of a formal authorization for its use. It’s unclear whether an EUA will lead to a major increase in the number of doctors capable of using convalescent plasma to treat Covid-19, and the number of patients who will end up receiving the treatment.

Aren’t some patients being treated with convalescent plasma already?

Yes, through “compassionate use” programs like the Mayo Clinic study, and through more rigorous clinical trials.

Isn’t the government already advertising convalescent plasma as a Covid-19 treatment?

Yes. FDA Commissioner Stephen Hahn began encouraging Americans sick with Covid-19 to donate plasma as early as April. The federal government, in fact, has already spent about $8 million on radio and online advertisements encouraging Americans to donate plasma, even though no government agency has formally endorsed its use.

Trump attended a roundtable on donating plasma last month at the American Red Cross national headquarters in Washington, D.C., accompanied by health secretary Alex Azar, Surgeon General Jerome Adams, and Tony Fauci, the director of the National Institute of Allergy and Infectious Diseases.

Hahn’s face has even appeared on FDA-branded billboard advertisements that encourage passers-by: “Help us save lives. Donate plasma now.”

Has there been pushback regarding use of convalescent plasma?

Yes. The New York Times reported on Wednesday that Fauci and the director of the National Institutes of Health recently intervened to discourage the FDA from issuing an EUA for convalescent plasma, citing concerns over weak data.

It’s not clear whether their reported pushback made a difference. Francis Collins, the NIH director, and Fauci are widely respected scientists but have no authority over FDA.

Scientists outside government have cast the convalescent plasma debate as a case study in pandemic-era science — and how the urgency of treating Covid-19 balances against the need for caution and due diligence in developing new medical treatments.

“It raises the question of what strength of evidence is necessary to treat during a pandemic,” Harlan Krumholz, director of the Center for Outcomes Research and Evaluation at Yale New Haven Hospital, told STAT recently. “The problem is we have yet to resolve what is sufficient evidence to change the treatment paradigm.”

  • It’s a nothingburger. I had to wait a month to donate convalescent plasma in Northern Virginia because so many people were signing up. (The Red Cross botched my registration process, so I’m trying again through Inova — which is so backed up that it has yet to get back to me.)

    CP is in use. Not just at the Mayo Clinic. No one was waiting on the FDA. Trump wants to take credit for something that already happened. (I joked that I was approving emergency use of Ambien.)

    Not sure why Fauci and company are fretting about it given that the horse left the barn a long time ago.

    • Thank you exposing the truth about #45’s “big announcement” to publicize his reality show TV “It’s All About Me & How I Profit Off You Dumb Fans”, oops, I mean, The Republican National Convention, illegally held at what is SUPPOSED to be the POLITICALLY NEUTRAL White House.
      I’m sorry you’ve gone through C19. Thank you for donating your plasma. I hope you and your loved ones are well and healthy.

    • I believe Fauci is concerned with getting real data so that we can actually know if this works. A double blind study etc to see if outcomes are really effected for the better or perhaps the worse. If a bunch of doctors are doing a bunch of random things, you never know if people are just recovering by themselves, whether they took other medications, what dose they got etc.

    • Ann, what are you talking about? Illegally held? And since when is there a neutrality requirement for anything done at the white house? Do you just make this stuff up as you go along? Maybe someone should have told Obama that when he directed the illegal surveillance of the Trump campaign where unverified, fabricated Russian propoganda as provided by Hillary Clinton in order to get FISA warrants. Not to mention the illegal unmasking of multiple Trump associates, illegal entrapment FBI interviews where they altered the 302’s to force Flynn to plead guilty to lying when he never lied.

      And FYI, being President has actually COST Trump money. He even donates his salary to charity.

      Now compare this to Obama who was fairly broke when he entered the white house and left with tens of millions of dollars. Or Biden’s son getting a 2 billion dollar investment from China, or millions from Ukraine? You’re projecting.

  • A recent poll conducted from Trump and other Republicans showed, “The total number of U.S. Covid 19 deaths were at acceptable numbers”. Unfortunately, some people are falling for this ploy of “Super Hero Donald” to win the election. If he were truly in touch with the American people, he would have already known about CB. Instead, on the eve of the Republican National Convention, Trump is trying to convince voters that he is the almighty savior! People WAKE UP and pull your heads out of the Sand! Some recovered C19 patients are and have been donating their plasma, in hope of saving a life.
    I had C19 and recovered without donated plasma, it was and still is a difficult process. People, this is the United States of America, Land of the Free not “Donald Trump’s Fantasy Land”
    I believe, some of us have forgotten, without SCIENCE, and the countless, selfless, heroic acts of the Doctors, Nurses and all other health care professionals involved…CP would not make a difference. Basically, it is a personal choice when donating “YOUR PLASMA”
    Wear a MASK to STOP THE SPREAD people, so you and/or your family and friends won’t need CP.
    FYI..I have given my plasma 2 times.

    • Thank you exposing the truth about #45’s “big announcement” to publicize his reality show TV “It’s All About Me & How I Profit Off You Dumb Fans”, pops, I mean, The Republican National Convention. Illegally held at what is SUPPOSED to be the POLITICALLY NEUTRAL White House.
      I’m sorry you’ve gone through C19. Thank you for donating your plasma. I hope you and your loved ones are well and healthy.

    • Masks are worthless. Since that isn’t scientific enough for you, even though you provided zero evidence that they do work. In fact, your entire post was nothing but trash talk in typical liberal fashion where you then try to shut people down by calling them anti-science. It’s pathetic.

      Here is actual documented scientific evidence based on 14 Randomized controlled trials which all concluded you are wrong.

      “Disposable medical masks (also known as surgical masks) are loose-fitting devices that were designed to be worn by medical personnel to protect accidental contamination of patient wounds, and to protect the wearer against splashes or sprays of bodily fluids (36). There is limited evidence for their effectiveness in preventing influenza virus transmission either when worn by the infected person for source control or when worn by uninfected persons to reduce exposure. Our systematic review found no significant effect of face masks on transmission of laboratory-confirmed influenza.”

      https://wwwnc.cdc.gov/eid/article/26/5/19-0994_article?fbclid=IwAR1wgGi1n82n8eGLEFTIbzV3atyHqop9DqK-rhx7itJ0SY3eZm5erwTZw6g

      Normal surgical masks have pore approx 0.3-10 microns, and viruses are 0.004 to 0.1 microns in size. What is essentially happening is you’re trying to stop mosquitos with a chain-link fence.

  • There is no debate as to how we should move forward, you follow the science. If this is a war against the virus, we should use our best weapons, science. We have tried everything else.

    • I totally agree. #BelieveScience Deplorable that I even have to type this, but: #BelieveFacts #PoliciesBasedOnScience

  • I don’t know anything about medicine but I have researched the corrupt UN for three years and am well aware that much of the indoctrination training from foreign influence ops is funneled through the UN.
    It is astonishing that our paid fools have allowed adversarial countries to invest in our universities for decades with no oversight from them. They specifically target science and media/journalism for indoctrination and own many of the scientists due to green grants for their Global Green Ponzi Scheme.
    I find it hard to believe that stat news is unaware that our FDA, NIH and too many of our politicians are owned by those who also own the WHO. Always follow the money and/or the intimidation. The indoctrinated are aggressively dangerous as “by any means necessary” means no compromise. They don’t just ignore those who disagree with them, they actively go after them. The bigger the threat, the harder they demonize. This is how I vet the honest scientists often called “climate deniers” or anyone else telling the truth.

    The UN started their “verified initiative” with their “digital first responders” who fact check social media for any cvirus info that is contrary to the WHO. Mail in voting is a byproduct of the virus so they censored our President. The UN news will tell you that they are working with Face book and Google to censor any and all things they can twist into being related to this virus like they do with everything.
    What’s going to happen when the rest of the general public realizes these health entities could care less whether or not HCQ helps anyone. Trump said it does so that means they have to find a way to make sure it doesn’t.
    Surely stat news understands this as you are in DC.

    • thank you that is so true and numerous people fall for the social part of it like they give a crap about you or your health, and deliberately go against the President so blatantly it’s crazy. Like he is on the Americans side and yet the senseless people really dont see what is right in front of them. I am sorry but when I look at many of the Democratic leaders that are in place right now, Pelosi, Newsom, Biden, Clintons, etc., I honestly just see pure evil like the devil!!

    • It’s not “research” to look in QAnon forums to get your information Cindy. That is being gullible and intellectually lazy. You might want learn more about reliable sources, critical thinking and ability to detect bias instead of trying to “research.” You called climate change deniers “honest scientists telling the truth,” however that shows that you don’t understand how science or medicine work.

  • “There is already evidence that antibody-rich blood, taken from people who have recently recovered from the coronavirus, could be used as a treatment. But the key trick with this llama-derived antibody therapy is that the scientists can produce coronavirus-specific antibodies to order.”
    https://www.bbc.com/news/science-environment-53369103

  • If what the NY Times report is true, then Fauci is part of the swamp… if a treatment has a 35% decrease in mortality if given early that is clinically significant. Why withhold the ability for a treatment that would save 35 of 100 lives? Pretty sad. Thanks to Trump and “warp speed” for allowing patients to have access to these lifesaving treatments through EUA.

    • and what if the effect they saw was due to those patients being treated differently (perhaps a bit better) because the medical team knew that they were being treated? That is why double-blind studies (placebo control) are NECESSARY. are you honestly suggesting that Fauci is in on some conspiracy? Your tinfoil hat must be on too tight…I think your math sucks, as well.

    • Abbey, I received the convalescent plasma and it helped me. Unless you have experienced the treatment and know it does not help then you have no right to say it might be a croc and should not be allowed. I’m sure glad they allowed me to have the treatment.

    • Supply is a major limiting factor. Plasma can only come from donors that have already recovered from Covid-19. It doesn’t mention here but blood type likely has to match as well. And how might using plasma and remdesivir together work or is that impractical due to supply issues. Important to know too is whether those that live have less severe complications, etc. I don’t believe what they have done so far is intended to answer those questions, hence moving to Phase III. Now I don’t know why Mayo did not use a placebo in their study but moving to the next phase will by definition require a placebo, which is an essential step. Oh, your math is too simplistic as well.

    • The rate is 3.2% not 35% perceived reduction in mortality for the convalescent therapy (because the tests did not have a placebo group}.

    • If it is effective in lowering the mortality rate when given early on, why not make it available as long as the adverse effects are minimal. If we have to wait for the CP to meet FDA requirements to be approved by FDA as a treatment, how many would die while waiting for the approval that could have been saved? 🤔

    • Abbie, You’re clearly blinded by an acute case of TDS. Have you ever been to India? I have, and it was the first time in my life where i witnessed true poverty. India is a textbook case of what should be a ‘worst case scenario” based on the incredibly close living conditions, lack of sanitation, and the fact that they’ve got well over a billion people. Ask yourself WHY the death rate in India so low? The same low death rates can be found in at least another dozen countries in Asia. What did they do different?

      What they all have in common is the use of a drug that has been around since the 1930’s and is typically prescribed to anyone visiting a country where malaria is a threat. All these countries are treating their populations with Hydroxychloroquine. Here is a 2005 study proving its effectiveness when treating both infected patients as well as those who could be exposed to SARS COVID. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1232869/

      If you actually think people like Fauci are unbiased, then please explain his own behavior where he has gone out of his way to promote flawed studies that have since been retracted regarding Hydroxy, one of which was from an eye doctor trying to push the very expensive remdesivir which he had financial stakes in. Or the brazillian study where fatal doses were given to patients.
      My brother works in the pharmaceutical industry. Some of his previous employers include Teva, Allergan, and Amgen. I recently asked him about Hydroxy and he flat out stated that there is no money in that drug for pharmaceutical companies. These companies have no shortage of lobbyists who likely pushed the right people to put the brakes on hydroxy.

  • I JUST read that it is being used for The Compassionate use program From Mayo Clinic and more rigorous clinical trials! What entails compassionate use?
    Where is that data? Positive or negative

  • This is a f****p! How could the NIH sponsor a study which had no control only to turn round later to argue against EUA on the same basis??

    The US has become a 3rd world country in the field of research. It cant put anything convincingly to bed. NIH/FDA need shakeups

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