Convalescent Plasma for COVID-19

Convalescent plasma is a new and promising treatment for the Novel Coronavirus Disease 2019 (COVID-19). There are 33,873,355 cases of COVID-19 around the world at the time of writing this article. In the United States there are 7,229,693 cases. 

The COVID-19 pandemic seems to be unrelentingly meddling in our everyday affairs. There have been many reports of potential treatments ever since this coronavirus, or severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), made its way around the globe. These treatment reports range from the now debunked hydroxychloroquine to the still interesting remdesivir and some corticosteroids. 

It seems like convalescent plasma is gaining popularity as scientists learn more about its benefits.

What is Convalescent Plasma?

Plasma is the watery part of your blood. It contains important proteins, mineral salts, sugars, fats, hormones, and vitamins. It accounts for about 55% of your blood. The other 45% are other blood components like your red blood cells, platelets, and white blood cells. 

So, what makes plasma “convalescent”?
When a person recovers from an infection, such as the flu or the common cold, their body makes proteins that are able to seek and help destroy viruses and bacteria that caused the illness. That means that if someone gets re-infected with the same virus, the body would be able to recognize that virus and get rid of it before it causes trouble again. These virus-seeking proteins, or antibodies, are found in an individual’s plasma. 

Convalescent plasma is plasma that is donated by a person who has had an infection and has subsequently recovered from it. Plasma is donated in a similar way as blood would be donated; in a blood donation center. The only difference is that plasma donation takes a bit longer and requires extra equipment. Donated plasma contains antibodies that can help treat a specific disease. For example, if a donor recovered from COVID-19, then they have antibodies against SARS-CoV-2. The recipient, who is sick from COVID-19, may receive that donor’s plasma through a transfusion and, in theory, recover faster from COVID-19. 

This idea may seem revolutionary but has been successfully used in the past. Convalescent plasma has been used to harvest antibodies and treat patients with viruses like hepatitis B and even Ebola. 

What does the Evidence say about Convalescent Plasma?

The Food and Drug Administration (FDA) recently issued an emergency use authorization (EUA) for convalescent plasma to be used in patients who have COVID-19.

The EUA is based on some evidence from an observational study showing that convalescent plasma can reduce COVID-19 mortality in critically ill patients. 

Evidence suggests that individuals who received convalescent plasma within 1-3 days of COVID-19 diagnosis were less likely to die than those who waited beyond 3 days for plasma transfusion. This means that earlier transfusion of convalescent plasma is more beneficial. Other evidence also shows that a higher dose of the plasma correlates with a more beneficial response.

However, some experts are skeptical about this evidence, including National Institute of Allergy and Infectious Diseases Director Dr. Anthony Fauci. 

The skepticism comes from the weak reliability of the data. Dr. Fauci argues that more robust studies should be undertaken before any decision can be reached about the effectiveness of convalescent plasma. So far, the data from this single study are promising, but not convincing. The study  also has not been peer-reviewed, which means it has not passed an important appraisal step in the scientific method. 

Convalescent plasma may cause some side effects. Some potential risks include transfusion-related events, like: 

• Chills
• Fever
• Anaphylaxis
• Lung injury
• Fluid overload
• Red blood cell damage

These side effects are mostly rare. However, because this particular therapy is very new and uncommon there are still possible risks that we have  not yet uncovered. 

The Need for Donors

The benefits and risks of treatments are continually being weighed as more data is available. At this time, convalescent plasma is an option for hospitalized patients with COVID-19. 

This means that plasma donors are needed.

Eligibility criteria to donate plasma are:

• Minimum age of 17 years and 110 lbs in weight 
• Good health status 
• History of a prior, verified diagnosis of COVID-19, 
  • Donor must be symptom free for at least 14 days at time of donation
  • Donor must also meet the requirements for blood donation 

One of the requirements to donate convalescent plasma for the purposes of treating COVID-19 is to have a confirmed diagnosis of COVID-19. This means donors would need to produce records of a positive test confirming infection. This automatically precludes many people from donating as not everyone had undergone COVID-19 screening.

Nonetheless, donating plasma is still a worthwhile endeavor and can potentially save lives as it can be used for many other purposes, like treating victims of trauma, burn, or shock.

Certain individuals are also labeled as “superdonors.” Their plasma contains very high levels of SARS-CoV-2 antibodies. The plasma from these superdonors is in high demand because it may help patients recover much faster from disease than convalescent plasma obtained from a “regular” donor. 

Bottom Line
Convalescent plasma is a potential treatment for COVID-19 because it uses the plasma of people who were previously infected with the novel coronavirus. Currently hospitalized patients who are suffering from COVID-19 are possible recipients of convalescent plasma. The therapy seems to offer benefit but has some risks as well. There is currently not enough evidence to say for certain what all these risks are.Despite this uncertainty, individuals who recovered from a confirmed case of COVID-19 are encouraged to donate their plasma. As the pandemic persists, new evidence of possible treatments continues to emerge, but convalescent plasma may be a step in the right direction. 

References

• Coronavirus Resource Center. Johns Hopkins University School of Medicine. Updated September 30, 2020. Accessed September 30, 2020. https://coronavirus.jhu.edu/map.html
• Coronavirus (COVID-19) Update: FDA Revokes Emergency Use Authorization for Chloroquine and Hydroxychloroquine. U.S. Food and drug Administration. June 15, 2020. Accessed September 29, 2020. https://www.fda.gov/news-events/press-announcements/coronavirus-covid-19-update-fda-revokes-emergency-use-authorization-chloroquine-and
• COVID-19 Update: FDA Broadens Emergency Use Authorization for Veklury (remdesivir) to Include All Hospitalized Patients for Treatment of COVID-19. U.S. Food and drug Administration. August 28, 2020. Accessed September 29, 2020. https://www.fda.gov/news-events/press-announcements/covid-19-update-fda-broadens-emergency-use-authorization-veklury-remdesivir-include-all-hospitalized
• WHO updates guidance on corticosteroids in Covid-19 patients. Pharmaceutical Technology. September 3, 2020. Accessed September 29, 2020. https://www.pharmaceutical-technology.com/news/who-corticosteroids-covid-advice
• The importance of plasma in blood. American Red Cross. Accessed September 29, 2020. https://www.redcrossblood.org/donate-blood/dlp/plasma-information.html
• Mayo Clinic Staff. Convalescent plasma therapy. Mayo Clinic. Accessed September 29, 2020. https://www.mayoclinic.org/tests-procedures/convalescent-plasma-therapy/about/pac-20486440
• van Griensven J, De Weiggheleire A, Delamou A, et al. The Use of Ebola Convalescent Plasma to Treat Ebola Virus Disease in Resource-Constrained Settings: A Perspective from the Field. Clin Infect Dis. 2016;62(1):69-74. doi:10.1093/cid/civ680
• Recommendations for Investigational COVID-19 Convalescent Plasma. U.S. Food and drug Administration. September 2, 2020. Accessed September 29, 2020 https://www.fda.gov/vaccines-blood-biologics/investigational-new-drug-ind-or-device-exemption-ide-process-cber/recommendations-investigational-covid-19-convalescent-plasma
• Joyner MJ, Senefeld JW, Klassen SA, et al. Effect of Convalescent Plasma on Mortality among Hospitalized Patients with COVID-19: Initial Three-Month Experience. Preprint. medRxiv. 2020;2020.08.12.20169359. Published 2020 Aug 12. doi:10.1101/2020.08.12.20169359
• Dearment A. Report: FDA halted move to authorize convalescent plasma for Covid-19 over evidence concerns. MedCity News. August 20, 2020. Accessed September 29, 2020. https://medcitynews.com/2020/08/report-fda-halted-move-to-authorize-convalescent-plasma-for-covid-19-over-evidence-concerns/
• Zhao Q, He Y. Challenges of Convalescent Plasma Therapy on COVID-19. J Clin Virol. 2020;127:104358. doi:10.1016/j.jcv.2020.104358
• Plasma Donations from Recovered COVID-19 Patients. American Red Cross. Accessed September 29, 2020. https://www.redcrossblood.org/donate-blood/dlp/plasma-donations-from-recovered-covid-19-patients.html
• Frequently Asked Questions. American Red Cross. Accessed September 29, 2020. https://www.redcrossblood.org/faq.html#eligibility
• What is Plasma? Donating Plasma.org. Accessed September 30, 2020. https://www.donatingplasma.org/donation/what-is-plasma
• Marcus AD. Wanted in Covid-19 Fight: ‘Superdonors’ of Convalescent Plasma. The Wall Street Journal. September 27, 2020. Accessed September 29, 2020. https://www.wsj.com/articles/wanted-in-covid-19-fight-super-donors-of-convalescent-plasma-11601211600