What to Know About COVID-19 Plasma Therapy
Researchers have been working diligently to find a solution to the COVID-19 pandemic. There are several avenues currently under exploration, including vaccines and therapeutic medicines to treat the infection. While both of these options take time to develop, there is another possibility that is more readily available—convalescent plasma therapy.
What is convalescent plasma therapy?
Convalescent plasma therapy uses antibodies from a donor to fight an infection in someone else. Convalescent means it is a therapeutic, to help the person recover from illness. Antibodies are proteins the immune system makes to fight germs, such as bacteria and viruses. Another name for antibody is immunoglobulin. When someone gets an infection, their immune system reacts and begins to make antibodies. After they recover from the infection, the antibodies usually provide protection against whatever germ was causing it. If the person is exposed to the germ again, the antibodies quickly recognize and attack the germ.
What is plasma?
Plasma is the liquid component of blood that contains antibodies and other substances. Separating plasma from blood cells allows doctors to infuse antibody-containing plasma into sick patients. This passive immunity gives the sick person a jumpstart on fighting the infection while their own immune system is still kicking in.
This type of passive immunity has been around for over 100 years. In the age before antibiotics, it was the only hope for many people. In the early part of the last century, doctors used it to treat bacterial infections, such as scarlet fever, and viral infections, such as the Spanish flu. More recently, doctors used it to battle MERS (Middle East respiratory virus) and SARS (severe acute respiratory syndrome) viruses. Naturally, this has led many to consider using it against the COVID-19 virus.
Does COVID-19 plasma therapy work?
This is a question researchers are currently trying to answer. To find out, they first need to know if antibodies to the COVID-19 virus, SARS-CoV-2, are indeed protective. Studies in monkeys have demonstrated that monkeys infected with the virus can’t be re-infected with it. This gave researchers hope that human antibodies to SARS-CoV-2 would be protective. They began to study if COVID-19 plasma therapy is safe and effective in humans.
The first U.S. trial looking at safety has released preliminary results on the first 5,000 patients to receive COVID-19 plasma therapy. All patients were hospitalized with severe or life-threatening COVID-19. Results suggest plasma therapy is safe, with a low number of serious adverse events. While these non-peer reviewed results are promising, this study doesn’t look at effectiveness. (Peer review means scientists in the same field but who have no connection with the study validated its methodology, results and conclusions.)
The gold standard for an effectiveness study is a randomized controlled clinical trial (patients are randomly assigned to receive either COVID-19 plasma or plasma from a non-infected donor). Currently, there are several of these trials active or in planning stages in the United States. Small studies in China suggest a positive effect of plasma therapy for COVID-19. Hopefully, the results of these larger rigorous U.S. trials will verify both the safety and effectiveness of COVID-19 plasma therapy.
What are the benefits and potential uses of COVID-19 plasma therapy?
Infusing plasma rich with antibodies to the COVID-19 virus could neutralize the virus in a sick person’s body. Ultimately, this could stop the devastating tissue damage the virus causes. In critically or seriously ill people, this has the potential to be lifesaving. But researchers are also looking at giving COVID plasma therapy to those at risk of progressing to severe disease. This could include people with underlying medical conditions that make them high-risk for a poor outcome. Giving it earlier in the disease before it becomes life threatening may prevent it from advancing to critical stages.
Another potential use for plasma therapy is disease prevention in exposed people. This prophylactic use would target healthcare providers who have known exposures to COVID-19. It could also benefit family members who are caring for someone with the disease. Giving antibodies to these people may prevent infection altogether.
What are the potential risks of COVID-19 plasma therapy?
Like any kind of medical treatment, convalescent plasma therapy carries potential risks. This includes the same risks present with any blood product, such as infection with another blood-borne disease and transfusion reactions. Other risks include:
- Antibody-dependent enhancement. This could occur when antibodies trigger a paradoxical worsening of the immune response. The result is an increase in immune-related tissue damage.
- Coagulation derangement. This could occur when the antibodies trigger a worsening of clotting problems that doctors have noted with advanced COVID-19.
So far, neither of these theoretical concerns have been a problem. U.S. doctors and researchers have used thousands of units of COVID-19 plasma without these problems occurring. Along with the early safety study results, this suggests COVID-19 convalescent plasma therapy is safe.
How do you donate or access COVID-19 plasma therapy?
If you are a patient or family member looking for COVID-19 plasma treatment, talk with your doctor. There are two avenues for getting COVID-19 plasma therapy outside of a clinical trial:
- Expanded access. This gives people access to treatment when they aren’t eligible for or able to participate in a clinical trial. Over 2,000 sites around the country can provide access. You can find more information at COVID-19 Expanded Access Program.
- Single patient emergency IND. This compassionate use program is for people who aren’t able to participate in a clinical trial or the expanded access protocol. Doctors must contact the FDA (Food and Drug Administration) directly for access.
If you have fully recovered from COVID-19 for at least two weeks, you may be able to donate your plasma. You must be free of symptoms for at least 14 days and test negative for the virus (which means you do not have an active infection). If you meet these criteria, you can find a list of places to donate plasma at Donate COVID-19 Plasma.
If you haven’t had COVID-19, you can still be part of the larger healthcare solution. The U.S. blood supply has taken a hit during this pandemic. Consider donating blood at your local donation center. Each donation has the potential to save up to three lives of people with a variety of diseases and conditions.