Everything You Need to Know About Convalescent Plasma and COVID-19
Is the FDA approval of this COVID-19 treatment due to good science or bad politics?
The Food and Drug Administration gave emergency approval for the use of convalescent plasma to treat COVID-19 on Sunday. This treatment uses the antibody-rich blood of people who have recovered from COVID-19 to treat those who have the disease. Though 70,000 COVID-19 patients have already received the treatment, the approval is controversial because there’s not enough data to prove that it works. The rushed authorization, which many top scientists are opposed to, came one day after President Trump repeated his unfounded claim that the FDA is delaying COVID-19 therapies and vaccines until after the presidential election in November. Some experts have interpreted this chain of events to mean that Trump is pushing for coronavirus therapies before they’re ready to make him look good to voters.
What does this mean for people who are just trying to survive the pandemic? If you’ve had COVID-19, should you donate your plasma? If you’re sick, should you ask for this treatment? This is everything you need to know.
What is Convalescent Plasma?
Plasma is the fourth major component of blood, along with red blood cells, white blood cells, and platelets, which help make blood clot. The plasma is liquid and yellow and carries around water, salts, and enzymes. It also contains antibodies, which are formed when the body fights off a particular viral or bacterial infection. Antibodies help kill that bacteria or virus if it makes a repeat appearance.
Convalescent plasma refers to blood plasma from someone who was infected with a disease that is transfused to someone who is still sick with it. The antibodies from the donor’s plasma can then fight off the infection in the recipient. In theory, this treatment helps the patient get better faster and prevents them from getting severely ill or dying.
Convalescent plasma has been used to treat diseases for about a century, particularly diseases new to humans that we have no natural defenses against. During the Spanish Flu pandemic of 1918, doctors used these transfusions to help patients. They have also used this treatment to fight SARS, Ebola, and swine flu, according to the New York Times. But convalescent plasma treatment has never been widespread enough for experts to reliably test how well it works.
COVID-19 and Convalescent Plasma
The FDA’s emergency approval of convalescent plasma to treat COVID-19 is based on more than 12 published studies, the agency said. However, just two of the studies the agency sited in its approval memo were randomized controlled trials, which are considered the gold standard in medical research. These trails both ended early — one because the researchers failed to enroll enough participants and the other because they found that the plasma recipients already had high levels of antibodies. Neither found much benefit of the treatment, Vox reports.
So far, 70,000 COVID-19 patients have been treated with convalescent plasma therapy in an agency program, according to Peter Marks, director of the FDA’s center for biologics evaluation and research. Marks said that when COVID-19 patients are given plasma with high levels of antibodies within three days of diagnosis, they have a 35 percent lower death rate one month later compared to those given plasma with low levels of antibodies. These numbers only apply to patients who are under 80 years of age and not on a ventilator. However, this figure comes from one pre-print study that has not yet been peer-reviewed for flaws. The study is not a randomized control trial and uses an experimental design more prone to bias. “There’s nothing wrong with the study itself for what it is,” Jeremy Faust, an emergency medicine specialist at Brigham and Women’s Hospital, told Vox. “What’s wrong is to rely on it to say that there’s been a breakthrough.”
Many experts say there’s not enough data to prove that convalescent plasma is effective as a COVID-19 treatment. The World Health Organization called the evidence “low quality” and supports continued testing over approval. The Infectious Disease Society of America endorses more randomized clinical trials before authorizing wide use of the treatment. Anthony Fauci, the top infectious disease specialist in the U.S., has also urged caution.
The FDA recognizes that they don’t have definitive proof the treatment is effective, but they say the approval is deserved anyway. The agency has “concluded convalescent plasma is safe and shows promising efficacy, thereby meeting criteria for an emergency use authorization,” FDA commissioner Stephen Hahn said at a press conference on Sunday night.
However, experts worry that an emergency use authorization (EUA) now means doctors will give the plasma without trying to enroll their patients in trials because if the patients do enroll, they may get a placebo instead of the treatment. “The biggest problem with an EUA for convalescent plasma therapy is that we will not know if it works, as the EUA essentially causes clinicians to give the treatment rather than entering patients in clinical trials,” Duncan Young, a professor of intensive care medicine at the University of Oxford, told Newsweek. “There may also be a rationing problem as it may be in short supply.”
Is Convalescent Plasma Dangerous?
Because there haven’t been enough trials run on convalescent plasma, experts don’t know for sure if it’s safe. “It’s not known if this treatment will or will not help those with COVID-19 or if it will have any harmful effects,” according to USCovidPlasma.org. Plasma transfusions in general can cause uncommon complications such as acute lung injury. However, the Mayo Clinic released a safety report in June from data of 20,000 convalescent plasma recipients suggesting the treatment is safe. Based on this evidence, Marks said, “We’re confident that convalescent plasma is safe to use in this setting.” And though many experts are protesting the approval on the grounds of unknown effectiveness, few have voiced concerns about safety.
While convalescent plasma transfusions may not be dangerous, health officials worry that Trump will push similar rushed approval of a COVID-19 vaccines in time for the November presidential election. If steps are skipped in vaccine evaluation, there is much more opportunity for harm. After all, that’s what happened with hydroxychloroquine in March after Trump repeatedly pushed for the anti-malaria drug as a COVID-19 treatment, according to Vox. In June, the FDA rescinded its emergency approval after finding that the drug was “unlikely to be effective” and can cause dangerous side effects such as heart arrhythmia.
How to Donate Convalescent Plasma for COVID-19 Treatment
If you have had COVID-19 and recovered, your plasma could treat patients sick with the disease and advance research into the treatment’s effectiveness. You must meet the general requirements to give plasma: be 18 or over, 110 pounds or over, and in good health, according to the Red Cross. To meet FDA guidelines, you also must have tested positive for the coronavirus but now be free of the virus for 28 days, or 14 days with a negative test. You can donate plasma every 28 days.
The plasma donation process is not like a normal blood donation. Usually, a phlebotomist would poke you with a needle connected to a hose and fill your blood up into a bag. In a plasma donation, you get stuck with a needle, but your blood is filtered through a machine that separates the liquid plasma from your red and white blood cells and platelets. Those are then mixed with a saline solution and pumped back into your body. The whole thing takes between 1.5 and 2.5 hours, according to the New York Times. Side effects are the same as normal blood donation, with dizziness possible. But if you’re donating, you’ve already defeated COVID-19, so you can probably handle it.
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