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  • Writer's pictureJoan Rothchild Hardin

Covid-19 Convalescent Plasma Antibodies



The US Federal Drug Administration (FDA) is issuing a call for donations of blood plasma from people who have fully recovered from COVID-19. The idea is to use the antibodies in this plasma to help people currently fighting the infection.

“If you have fully recovered from COVID-19, you may be able to help patients currently fighting the infection by donating your plasma. Because you fought the infection, your plasma now contains COVID-19 antibodies. These antibodies provided one way for your immune system to fight the virus when you were sick, so your plasma may be able to be used to help others fight off the disease.

“Convalescent plasma is the liquid part of blood that is collected from patients who have recovered from the novel coronavirus disease, COVID-19, caused by the virus SARS-CoV-2. COVID-19 patients develop antibodies in the blood against the virus. Antibodies are proteins that might help fight the infection. Convalescent plasma is being investigated for the treatment of COVID-19 because there is no approved treatment for this disease and there is some information that suggests it might help some patients recover from COVID-19.”

People eligible to donate “have fully recovered from COVID-19 for at least two weeks…. COVID-19 convalescent plasma must only be collected from recovered individuals if they are eligible to donate blood. Individuals must have had a prior diagnosis of COVID-19 documented by a laboratory test and meet other donor criteria. Individuals must have complete resolution of symptoms for at least 28 days before they donate, or alternatively have no symptoms for at least 14 days prior to donation and have a negative lab test for active COVID-19 disease.” (US FDA, 2020)

If you qualify, you can donate convalescent plasma by contacting the American National Red Cross or the Plasma Protein Therapeutics Association to see the full list of eligibility requirements and find a donation site near you:


From a sampling of four recent articles:

  • A new study of recovered coronavirus patients found that patients develop different levels of antibodies to the virus. 

  • Ten patients of the 175 studied — 6% — didn’t have any detectable coronavirus antibodies in their systems. 

  • The study found that elderly and middle-aged people developed higher levels of antibodies.

“In the 10 patients in the study who did not develop detectable antibodies, ‘other immune responses, including T cells or cytokines, may contribute to the recovery,’ the researchers wrote.

“T cells are a type of white blood cells that aid in immune response, and cytokines are a type of molecule that cells release to fight infections. However, when too many cytokines are released, they cause inflammation — which has reportedly contributed to fatal outcomes in some COVID-19 patients.

“Even in patients who do develop coronavirus antibodies, scientists still aren’t sure how long they’ll last; the virus has not been around long enough to study long-term effects.

“Generally, once your body has antibodies to fight off a particular disease, you can’t get it again, though some types of antibodies weaken over time. Plus, with viruses that mutate — such as the common cold or seasonal flu — antibodies people build up against one strain aren’t effective against others.”

– Secon, 4/11/2020


A Journal of the American Medical Association (JAMA) article titled The Promise and Peril of Antibody Testing for COVID-19 raises questions about the current state of antibody testing.

“Unlike polymerase chain reaction (PCR) tests—also referred to as molecular or nucleic acid–based tests—antibody tests aren’t intended to identify active SARS-CoV-2 infections. Instead of detecting viral genetic material in throat or nasal swabs, antibody tests reveal markers of immune response—the IgM and IgG antibodies that for most people show up in blood more than a week after they start to feel sick, when symptoms may already be waning.

“Serologic antibody tests not only can confirm suspected cases after the fact, they can also reveal who was infected and didn’t know it. Up to a quarter of people with SARS-CoV-2 infection may unwittingly spread the virus because they have mild or no symptoms….

“In their first therapeutic application, serology tests are being used to screen donor blood for antibodies to SARS-CoV-2. Plasma containing the antibodies from recovered patients is then transfused to gravely ill patients in an experimental treatment known as convalescent plasma. Early results from a small number of Chinese patients, published in JAMA in late March, were promising…. “However, a substantial number of the new commercial COVID-19 antibody tests aren’t ELISA-based* (see note below). They’re lateral flow assays, which provide a simple positive or negative result, with no quantitative information. These kits are cheap and easy to use and, depending on how they’re employed, may be helpful for disease surveillance, Elitza Theel, PhD, director of the Mayo Clinic Infectious Diseases Serology Laboratory in Rochester, Minnesota, said in an interview…. “Although commercial manufacturers claim their tests have high sensitivity and specificity, they haven’t published their data yet. This lack of transparency is worrisome, Theel said: “The question is, when following symptom onset were these samples collected to show that sensitivity and specificity?”

“Her laboratory has found that most people with SARS-CoV-2 don’t start producing antibodies—or seroconvert—until at least 11 to 12 days after symptom onset. “So, if we were using these rapid lateral flow assays at the point of care to test recently symptomatic patients,…they are more likely than not going to be negative,” she said.”

* Note: ELISA = an “enzyme-linked immunosorbent assay”, a common laboratory platform that can measure antibody titers.

– (Abbasi, 4/17/2020)

Source: Gulf News

An April 17 2020 article (updated today, 4/19/2020) titled WHO warning: No evidence that antibody tests can show coronavirus immunity states The World Health Organization “said there’s no evidence serological tests can show whether a person has immunity or is no longer at risk of becoming reinfected.” (Lovelace & Feuer, 4/17/2020, updated 4/19/2020) See this 4/17/2020 video from WHO :

A fourth source of information, a New York Times article published today (4/19/2020) titled Antibody Test, Seen as Key to Reopening Country, Does Not Yet Deliver, describes the many problems with COVID-19 antibody tests as they exist at the moment.

“The tests, many made in China without F.D.A. approval, are often inaccurate. Some doctors are misusing them. The rollout is nowhere close to the demand.” (Eder, Twohey & Mandavilli, 4/19/2020)



Let’s fervently hope the US government, which so far has seriously bungled the entire Coronavirus-19 situation, can grow up, act responsibly and somehow get it together now.

Our country was egregiously unprepared for this or any other pandemic:

  • Comprehensive testing was delayed and still remains inadequate

  • Health officials have been ill prepared to gauge the spread of the virus and identify carriers

  • Adequate essential supplies and equipment have been dangerously unavailable to health care workers

  • Information provided about the virus has been both inconsistent and inaccurate

  • Federal and state agencies have failed to coordinate their efforts

The magnitude of this dangerous public health failure is mind boggling.

See 5 Ways the U.S. Botched the Response to COVID-19, from the Bloomberg School of Public Health at Johns Hopkins, for the gory details of these immense failures.

The article concludes with the question: So how can future public health crises be prevented? – and suggests these answers:

Sandra C. Quinn, chair of the Department of Family Health at the University of Maryland’s School of Public Health, stresses the importance of maintaining consistent funding for public health preparedness planning. She points out the sad fact that, “When the problem goes away, the funding goes away”.

Thomas A. Burke, PhD, MPH, professor and associate chair of Health Policy and Management at Johns Hopkins’ Bloomberg School of Public Health, points out that, for decades, public health leaders have sounded the alarm that the Strategic National Stockpile had an inadequate number of masks, personal protective gear and ventilators to face a pandemic. Recent reports indicate that this stockpile is nearly depleted. “I hope this is a big wake up call,” says Burke. “We’re all in this together, and we need to reinvest in our health care system and our public health system.”

And this should also now be abundantly clear: “U.S. public health policy must be guided by science, including recommendations offered in the Global Health Security Index.”

– Scharper, J. (4/3/2020)

Source: Stanford University Graduate School of Business


Abbasi, J. (4/17/2020). The Promise and Peril of Antibody Testing for COVID-19. Journal of the American Medical Association. See:

American National Red Cross. (2020). Plasma Donations from Recovered COVID-19 Patients. See:

Eder, S., Twohey, M. & Mandavilli, A. (4/19/2020). Antibody Test, Seen as Key to Reopening Country, Does Not Yet Deliver. The New York Times. See:

Lovelace, B. & Feuer, W. (4/17/2020). WHO warning: No evidence that antibody tests can show coronavirus immunity. CNBC. See:

Plasma Protein Therapeutics Association. (2020). Novel Coronavirus Disease (COVID-19) Resources. Donating See:

Scharper, J. (4/3/2020). 5 Ways the U.S. Botched the Response to COVID-19. Johns Hopkins Bloomberg School of Public Health. See:

Secon, H. (4/11/2020). New research raises questions about coronavirus immunity: 6% of recovered patients in one study didn’t develop antibodies at all. Business Insider. See:

© Copyright 2020. Joan Rothchild Hardin. All Rights Reserved.

DISCLAIMER:  Nothing on this site or blog is intended to provide medical advice, diagnosis or treatment.


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