Critiques of Trials 

In this section we provide critiques of some of the published randomized trials of COVID-19 convalescent plasma. Some of these have appeared in the journals that published the trial commented on, but not all.  This section will be continuously updated. 

Letter to the Editor: Knowlson et al.

This letter contests the claim in a paper in Health Science Reports that claimed that the Emergency Use Authorization for convalescent plasma discouraged the conduct of randomized trials. The paper has been accepted for publication in the journal.

High-titre convalescent plasma is easier than ever to procure

This paper documents the high levels of anti-spike protein antibodies to the Covid-19 virus among Italian blood donors, the result of nearly three years of COVID disease and vaccination.  It is likely that the same would be found in US blood donors, indicating that it should be relatively easy to find suitably potent convalescent plasma simply by testing routinely contributed plasma units.

Convalescent plasma therapy in COVID-19: Unravelling the data using the principles of antibody therapy

This paper provides an overview of the effectiveness of convalescent plasma but differs from many previous meta-analyses and systematic reviews by critically examining studies in light of key biological principles of antibody therapy.  The authors (the CCPP19 leadership team led by Arturo Casadevall joined by colleagues David Sullivan and Danielle Focosi) show that studies that adhered most closely to these principles – treatment early in the disease, of patients not yet severely ill, and with specific antibody of sufficiently high dose – tended to show the effectiveness of convalescent plasma.  By contrast, the several randomized trials that treated patients already oxygen or ventilator dependent, or late in the course of illness, or using plasma with insufficient antibody, generally failed to show effectiveness.  The ancient medical principle that we must treat the right patient with the right dose of the right medicine at the right time is once again reaffirmed.

Ordering High Titer Convalescent Plasma for an Immunocompromised Patient With Active COVID-19

Resources for the administration and ordering of vax-plasma. 

Misinterpretation of Clinical Research Findings and COVID-19 Mortality 

The first 3 years of the COVID-19 pandemic witnessed an unprecedented pace of research that delivered vaccines, antiviral agents, and anti-inflammatory therapies that dramatically lessened the morbidity and mortality of COVID-19. However, some research findings led to clinical practice recommendations that were later associated with excessmortality.

Convalescent Plasma Evidence Update 

Slide deck: Efficacy of high titer CCP in the treatment of COVID-19, including its utility in IC patients.

Once-favored Covid drugs ineffective on Omicron may be putting millions at risk

January 1, 2023

"The FDA has authorized the emergency use of convalescent plasma containing high Covid antibody levels for immunocompromised patients. But NIH has remained neutral on the treatment in that population, which Janet Handal, president of the Transplant Recipients and Immunocompromised Patient Advocacy Group, says has led to some hospitals balking at administering it."

As COVID Treatments Dwindle, Are New Ones Waiting in the Wings?

December 12, 2022

"Others suggest it's time to resurrect interest in convalescent plasma, a treatment used early in the pandemic before drugs or vaccines were here and still authorized for use in those who are immunosuppressed or receiving immunosuppressive treatment."

CCPP Leadership Group additional thoughts on Sullivan et al., 2022, and commenting editorial

June 24, 2022

The Sullivan et al trial was published by the New England Journal of Medicine (NEJM) in April 2022. The editorial found here prompted the CCPP19 Leadership Group to write to NEJM. The unpublished letter written by Dr. Henderson can be found here.  

COVID Convalescent Plasma Finds a Therapeutic Role

June 20, 2022

"Growing evidence shows benefits in the immunocompromised."


Arturo Casadevall, a member of the CCPP19 leadership team has been elected to the National Academy of Science

May 23, 2022

"Arturo Casadevall, MD, PhD, Bloomberg Distinguished Professor, and Alfred and Jill Sommer Professor and Chair of the Department of Molecular Microbiology and Immunology at the Bloomberg School, has been elected to the National Academy of Sciences in recognition of his furthering the understanding of fungal pathogenesis. Congratulations, Arturo!"

How the Food and Drug Administration saved thousands of lives

May 23, 2022

Drs. Arturo Casadevall and Nigel Paneth speak on the FDA's decision to make convalescent plasma accessible during the COVID-19 pandemic. 

Convalescent plasmas donors show enhanced cross-reactive neutralizing antibody response to antigenic variants of SARS-CoV-2 following immunization

May 20, 2022

The above paper shows that hybrid “VaxPlasma” from donors who have been vaccinated & recovered from infection can be very high titer and neutralize a wide variety of variants. It also links commercial assay values to in vitro neutralization data.

Letter to WHO asking for revisions to CCP recommendation

April 29, 2022

A link to sign the letter online can be found here.

Early Outpatient Treatment for Covid-19 with Convalescent Plasma

April 19, 2022

David Sullivan and Johns Hopkins colleagues (NEJM March 30, 2022) conducted a randomized trial of over 1,000 adults of all ages and risk levels and showed that outpatient treatment within 9 days of symptom onset with high antibody titer convalescent plasma reduced hospitalizations by more than 50%. If treatment was provided within 5 days of symptom onset, progression to more severe disease was reduced by 80%. This research highlights the value of early high-dose outpatient treatment with convalescent plasma as the place to start therapies in a new pandemic.

Latest update of convalescent plasma efficacy from Drs. Joyner and Casadevall prepared for Rita Reik, MD, Chief Medical Officer for One Blood. 

April 15, 2022


Recommendation for Convalescent Plasma from the IDSA

February 9, 2022

“The Infectious Disease Society of America (IDSA) has revised its recommendation on convalescent plasma to recommend outpatient use of high-titer convalescent early in the illness for high-risk patients with no other therapeutic options.”

Critique of World Health Organization Statement on Convalescent Plasma 

February 9, 2022

On December 13, 2021, The World Health Organization (WHO) released new advice on convalescent plasma treatment. Dr. Arturo Casadevall's critique of the WHO advice can be found here. The CCPP19 Leadership group has responded to the WHO recommendation on convalescent plasma in COVID-19. The critique is posted here

The European Blood Alliance has issued two critiques of the WHO advice, which can be found here and here.


COVID treatment warrants fresh look

February 6, 2022

"Klobuchar, other state leaders should heed the call for help on convalescent plasma."


Tool Pinpoints Who May Benefit From COVID Convalescent Plasma

January 26, 2022

"While a large meta-analysis of studies on convalescent plasma use early in the pandemic turned up no survival advantage for the typical patient hospitalized for COVID-19, researchers have mined the dataset to predict who may benefit."

Early Use of Convalescent Plasma May Help Outpatients with COVID-19 Avoid Hospitalization

January 5, 2022

"Eventually, we hope that our data will guide clinicians in how to effectively use high-titer convalescent plasma as an early outpatient treatment, especially regarding timing and dosage."

America's Blood Centers (ABC) Statement on Convalescent Plasma in COVID-19

January 5, 2022

ABC issues a statment supporting use of convalescent plasma in COVID-19, but acknowledges operational difficulties. 

FDA Authorizes Use of Outpatient COVID-19 Convalescent Plasma in Immunosuppressed Patients

December 28, 2021

On December 28th , the FDA authorized, for the first time, outpatient use of COVID-19 convalescent plasma, a key goal of CCPP19. 

While the authorization is only for “patients with immunosuppressive disease or receiving immunosuppressive treatment”, it allows physicians to treat their patients with COVID who have difficulty forming antibodies to the SARS CoV-2 virus to receive convalescent plasma at a time when it will be most likely to help them, and not have to wait for hospitalization, by which time the window of convalescent plasma effectiveness might have closed.

The announcement letter can be found here with the key paragraphs on pages 2 and 3 highlighted.

Johns Hopkins Trial in Out-Patients Shows that Convalescent Plasma can Lower Hospitalizations by 54%

December 21, 2021

Johns Hopkins Trial in Out-Patients Shows that Convalescent Plasma can Lower Hospitalizations by 54%


Please Reevaluate the Data on Convalescent Plasma for COVID-19 

August 28, 2021
"Early administration with high antibodies may offer hope to some patients."
Letters from others to NEJM about the SIREN-C3PO Trial (Korley et al) can be found here

UBI Cofounder Aviva Klein Receives Diana Award for CCP Donor Recruitment Leadership

July 23, 2021
"Aviva Klein was recently named a 2021 recipient of the Diana Award, which honors young people for social action and humanitarian efforts. Klein received the award for her advocacy to increase and improve the supply of COVID-19 convalescent plasma (CCP) throughout the COVID-19 pandemic."

Top Ten Projects in Health

June 2021
"What started with an academic paper quickly transformed into a virtual effort to collaborate, explore and accelerate the development of a possible treatment for those afflicted by the coronavirus."

A Victory for Scientific Pragmatism

March 25, 2021
"In an emergency, the “gold” standard of evidence may not be the wise one."

For early testing of convalescent plasma, we were ‘building the plane while we were flying it’

March 4, 2021
“During the Covid-19 pandemic, clinicians have seen many remarkable things. Among them is how a 19th-century therapy called convalescent plasma came to be used in more than 500,000 hospitalized Covid-19 patients the United States and elsewhere. Because we’ve had front-row seats on this journey, we’d like to offer answers to two key questions: How did this happen? Is it safe and does it work? ”

Convalescent plasma: a quality COVID treatment unnecessarily mired in controversy | COMMENTARY

January 24, 2021
Fortunately, we have convalescent plasma available, which could take a bite out of COVID-19 by saving lives and protecting our health care system from collapse.

A Little Debate on Plasma Is Healthy for Science - Opinion

September 22, 2020
“The FDA says it's likely effective, while NIH urges caution. The answer: get more data from trials. ”

FDA Made the Right Call on Covid Plasma Treatment - Opinion

August 28, 2020

How Politics Muddied the Waters on a Promising COVID-19 Treatment

July 25, 2020
“On the eve of the Republic National Convention, Trump pressured the FDA to allow emergency use of convalescent plasma- before the agency was ready to do so.

Medical Experts Say We Need a Second Shutdown to Control COVID-19

July 30, 2020
“In an open letter, also sent to the Trump administration, over 150 medical experts and other professionals are pleading for a second lockdown to address the steep rise in COVID-19 cases.

Researchers ask if survivor plasma could prevent coronavirus

June 12, 2020
“Survivors of COVID-19 are donating their blood plasma in droves in hopes it helps other patients recover from the coronavirus. And while the jury’s still out, now scientists are testing if the donations might also prevent infection in the first place.”

Convalescent plasma: ‘Flavor of the month’ or valid COVID-19 treatment?

May 26, 2020
“On March 31, soon after the Food and Drug Administration authorized emergency use of antibody-packed plasma from recovered patients with COVID-19, Marisa Leuzzi became the first donor at an American Red Cross center. She hoped it could help her aunt, Renee Bannister, who was failing after 3 weeks on a ventilator at Virtua Hospital in Voorhees, N.J.”

Using convalescent blood to treat COVID-19: The whys and hows

May 22, 2020
“Some researchers and doctors have started using plasma from people recovering from COVID-19 to treat others who have developed the disease. Medical News Today spoke to Dr. Arturo Casadevall, from Johns Hopkins University, to learn more about this approach.”

Convalescent Plasma Is Safe to Treat Covid-19, National Study Shows

May 14, 2020
“First large-scale analysis of patients receiving experimental treatment for coronavirus is expected to lead to more trials to test effectiveness of therapy.”

Covid-19 Raises Questions About the Value of Personalized Medicine

May 8, 2020
“A group of medical dissenters argues that tailoring treatment to the genetic profiles of individuals, a longstanding goal for researchers, is less important than the old-fashioned public health measures being used against the pandemic.”

Convalescent serum lines up as first-choice treatment for coronavirus

May 7, 2020
“Antibodies from blood donated by people who recovered from the illness and hyper-immunoglobulins are becoming treatments of choice for COVID-19, with recombinant polyclonal antibody approaches to follow.”

What Is Convalescent Plasma, and Why Do We Care About It?

April 24, 2020
“A medical procedure doctors have used to treat novel diseases for a century has emerged as a focal point in the fight against Covid-19: convalescent plasma.”

The FDA just approved Columbia's COVID-19 plasma therapy study, backed by Amazon

April 23, 2020
“FDA just greenlight a study to determine whether plasma collected from recently recovered Covid-19 patients help protect health care workers and alleviate symptoms in those who are severely ill from the virus.”

Hundreds Receive Plasma From Recovered Coronavirus Patients in National Study (PDF)

April 21, 2020
“Six hundred severely ill Covid-19 patients have received blood plasma from recovered patientsin a study researchers hope sheds light on whether the experimental therapy improves healthoutcomes and yields other useful data outside the scientific rigor of a traditional clinical trial.”

Coronavirus (COVID-19) Update: FDA Encourages Recovered Patients to Donate Plasma for Development of Blood-Related Therapies

April 16, 2020
“During this challenging time, many people are asking what they can do to contribute to the COVID-19 response. Those individuals who have recovered from COVID-19 could have an immediate impact in helping others who are severely ill. In fact, one donation has the potential to help up to four patients. Convalescent plasma can also be used to manufacture a biological product called hyperimmune globulin, which can similarly be used to treat patients with COVID-19.”

Why Blood From Coronavirus Survivors Could Be a Lifeline for the Sick

April 10, 2020
“In theory, doctors can transfer these antibodies to a person who is still sick, so these proteins can help them recover.”

Plasma treatment showing promise in Houston coronavirus patients

April 9, 2020
Houston is leading the way in research to help patients recover for coronavirus. One treatment is showing promise in Houston patients battling the virus.

29-year-old COVID-19 patient treated with Israel's new ‘passive vaccine’

April 12, 2020
“A 29-year-old haredi (ultra-Orthodox) coronavirus patient who is being treated at Samson Assuta Ashdod University Hospital has improved from serious to serious but stable condition, after receiving multiple doses of plasma over the weekend from a donor who recovered from coronavirus, a spokesperson for the hospital told The Jerusalem Post.”

Searching for a coronavirus cure in the blood

April 7, 2020
“Scientists look to convalescent plasma, hyperimmune therapy, and monoclonal antibodies to treat COVID-19”

Mayo Clinic named national site for Convalescent Plasma Expanded Access Program

April 3, 2020
“We are pleased to work with our colleagues and the nation to fight this pandemic every way we can as part of Mayo's patient-focused mission," Dr. Joyner says. "We believe this program, in extending access to this investigational treatment, is a hopeful therapeutic option.”

Johns Hopkins Gets FDA OK to Test Blood Therapies for COVID-19 Patients

April 3, 2020
“The U.S. Food and Drug Administration approved a clinical trial Friday that will allow Johns Hopkins University researchers to test a therapy for COVID-19 that uses plasma from recovering patients.”

NYCB Plasma Collection Release

April 3, 2020
“NYBC is one of the largest independent blood centers in the world. Its network serves local communities in New York, New Jersey, Connecticut, Pennsylvania, Delaware, Maryland, Virginia, Missouri, Kansas, Minnesota, Nebraska and Rhode Island. NYBC anticipates collecting convalescent plasma collections across these locations and the pandemic intensifies in locations across the US.”

Investigational COVID-19 Convalescent Plasma - Emergency INDs

April 2, 2020

“FDA has worked with multiple federal partners and academia to open an expanded access protocol to facilitate access to COVID-19 convalescent plasma. For patients with, or at risk of, severe or life-threatening COVID-19 disease who are not eligible or who are unable to participate in randomized clinical trials, access may be available through participation of acute care facilities in an investigational expanded access protocol under an IND already in place”

Could plasma from recovered COVID-19 patients help others?

April 2, 2020

“As new cases of COVID-19 mount daily, treatment revolves around supportive therapy to reduce symptoms, meaning there are no treatments shown to slow down or kill the SARS-CoV-2 virus. One new idea actually isn’t so new: transfusing blood plasma from recovered COVID-19 patients into patients currently sick with the disease.”

FDA authorizes first antibody-based test for COVID-19

April 2, 2020

“When someone is infected with a virus for the first time, their immune system begins producing antibodies specific to that virus. Checking to see if someone has coronavirus-specific antibodies is good evidence that they’ve been infected.”

FDA Approves First Coronavirus Antibody Test in U.S.

April 2, 2020

“Such a test may help scientists learn how widespread the infection is, and how long people remain immune after recovering.”

Ten Weeks to Crush the Curve

April 1, 2020

“The President says we are at war with the coronavirus. It’s a war we should fight to win. The aim is not to flatten the curve, the goal is to crush the curve.”

Mayo Clinic, Amazon join project to fight COVID-19 with harvested plasma from recovered patients

March 24, 2020

"A team of Mayo Clinic researchers are part of a national effort to develop a potential weapon against COVID-19 — one that could be ready in weeks, not months — by collecting blood plasma from patients who have recovered from the disease."