Convalescent Plasma for the Treatment of COVID-19 Patients?

Kathleen Doheny

April 16, 2020

Editor's note: Find the latest COVID-19 news and guidance in Medscape's Coronavirus Resource Center.

As an Episcopal priest, Father Robert Pace of Fort Worth, TX, is used to putting others first and reaching out to help. So when the pulmonologist who helped him through his ordeal with COVID-19 asked if he would like to donate blood to help other patients, he did not hesitate.

"I said, 'Absolutely,'" Pace, 53, recalls. He says the idea was ''very appealing." During his ordeal with COVID-19 in March, he had spent 3 days in the hospital, isolated and on IV fluids and oxygen. He was short of breath, with a heartbeat more rapid than usual.

Father Robert Pace

Now, fully recovered, his blood was a precious commodity, antibody-rich and potentially life-saving.

As researchers scramble to test drugs to fight COVID-19, others are turning to an age-old treatment. They're collecting the blood of survivors and giving it to patients in the throes of a severe infection, a treatment known as convalescent plasma therapy.

Doctors say the treatment will probably serve as a bridge until other drugs and a vaccine become available.

Although the FDA considers the treatment investigational, in late March, it eased access to it. Patients can get it as part of a clinical trial or through an expanded access program overseen by hospitals or universities. A doctor can also request permission to use the treatment for a single patient.

"It is considered an emergent, compassionate need," says John Burk, MD, a pulmonologist at Texas Health Harris Methodist Hospital, Fort Worth, who treated Pace. "It is a way to bring it to the bedside." And the approval can happen quickly. Burk says he got one from the FDA just 20 minutes after requesting it for a severely ill patient.

How It Works

The premise of how it works is ''quite straightforward," says Michael Joyner, MD, a professor of anesthesiology at the Mayo Clinic, Rochester, MN. "When someone is recovered and no longer symptomatic, you can harvest those antibodies from their blood and give them to someone else, and hopefully alter the course of their disease." Joyner is the principal investigator for the FDA's national Expanded Access to Convalescent Plasma for the Treatment of Patients with COVID-19, with 1,000 sites already signed on.

Convalescent therapy has been used to fight many other viruses, including including Ebola, severe acute respiratory syndrome (SARS), the "bird" flu, H1N1 flu, and during the 1918 flu pandemic. Joyner says the strongest evidence for it comes from the 1950s, when it was used to treat a rodent-borne illness called Argentine hemorrhagic fever. Using convalescent plasma therapy for this infection reduced the death rate from nearly 43% before the treatment became common in the late 1950s to about 3% after it was widely used, one report found.

Data about convalescent therapy specifically for COVID-19 is limited. Chinese researchers reported on five critically ill patients, all on mechanical ventilation, treated with convalescent plasma after they had received antiviral and anti-inflammatory medicines. Three could leave the hospital after 51-55 days, and two were in stable condition in the hospital 37 days after the transfusion.

In another study of 10 severely ill patients, symptoms went away or improved in all 10 within 1 to 3 days after the transfusion. Two of the three on ventilators were weaned off and put on oxygen instead. None died.

Chinese researchers also reported three cases of patients with COVID-19 given the convalescent therapy who had a satisfactory recovery.

Researchers who reviewed the track record of convalescent therapy for other conditions recently concluded that the treatment doesn't appear to cause severe side effects and it should be studied for COVID-19.

Although information on side effects specific to this treatment is evolving, Joyner says they are "very, very low."

According to the FDA, allergic reactions can occur with plasma therapies. Because the treatment for COVID-19 is new, it is not known if patients might have other types of reactions.

Who Can Donate?

Blood bank officials and researchers running the convalescent plasma programs say the desire to help is widespread, and they've been deluged with offers to donate. But requirements are strict.

Donors must have evidence of COVID-19 infection, documented in a variety of ways, such as a diagnostic test by nasal swab or a blood test showing antibodies. And they must be symptom-free for 14 days, with test results, or 28 days without.

The treatment involves collecting plasma, not whole blood. Plasma, the liquid part of the blood, helps with clotting and supports immunity. During the collection, a donor's blood is put through a machine that collects the plasma only and sends the red blood cells and platelets back to the donor.

Clinical Trials

Requirements may be more stringent for donors joining a formal clinical trial rather than an expanded access program. For instance, potential donors in a randomized clinical trial underway at Stony Brook University must have higher antibody levels than required by the FDA, says study leader Elliott Bennett-Guerrero, MD, medical director of perioperative quality and patient safety and professor at the Renaissance School of Medicine.

Julia Sabia Motley and Sean Motley both recovered from COVID-19 and hope to donate their blood to help other patients.

He hopes to enroll up to 500 patients from the Long Island, NY, area. While clinical trials typically have a 50-50 split, with half of subjects getting a treatment and half a placebo, Bennett-Guerrero's study will give 80% of patients the convalescent plasma and 20% standard plasma.

Julia Sabia Motley, 57, of Merrick, NY, is hoping to become a donor for the Stony Brook study. She and her husband, Sean Motley, 59, tested positive in late March. She has to pass one more test to join the trial. Her husband is also planning to try to donate. "I can finally do something," Sabia Motley says. Her son is in the MD-PhD program at Stony Brook and told her about the study.

Many Questions Remain

The treatment for COVID-19 is in its infancy. Burk has given the convalescent plasma to two patients. One is now recovering at home, and the other is on a ventilator but improving, he says.

About 200 nationwide have received the therapy, Joyner says. He expects blood supplies to increase as more people are eligible to donate.

Questions remain about how effective the convalescent therapy will be. While experts know that the COVID-19 antibodies "can be helpful in fighting the virus, we don't know how long the antibodies in the plasma would stay in place," Bennett-Guerrero says.

Nor do doctors know who the therapy might work best for, beyond people with a severe or life-threatening illness. When it's been used for other infections, it's generally given in early stages once someone has symptoms, Joyner says.

Joyner says he sees the treatment as a stopgap ''until concentrated antibodies are available." Several drug companies are working to retrieve antibodies from donors and make concentrated antibody drugs.

"Typically we would think convalescent plasma might be a helpful bridge until therapies that are safe and effective and can be mass-produced are available, such as a vaccine or a drug," Bennett-Guerrero says.

Even so, he says that he doesn't think he will have a problem attracting donors, and that he will have repeat donors eager to help.

More Information for Potential Donors

Blood banks, the American Red Cross, and others involved in convalescent plasma therapy have posted information online for potential donors. People who don't meet the qualifications for COVID-19 plasma donations are welcomed as regular blood donors if they meet those criteria.

According to the FDA, a donation could potentially help save the lives of up to four COVID-19 patients.

Father Pace is already planning another visit to the blood bank. To pass the time last time, he says, he prayed for the person who would eventually get his blood.


Father Robert Pace, Fort Worth, TX.

John Burk, MD, pulmonologist, Texas Health Harris Methodist Hospital, Fort Worth.

Michael Joyner, MD, professor of anesthesiology, principal investigator, Convalescent Plasma Expanded Access Program, Mayo Clinic, Rochester, MN.

Elliott Bennett-Guerrero, MD, medical director of perioperative quality and patient safety; professor, Renaissance School of Medicine, Stony Brook University, NY.

Julia Sabia Motley, 57, Merrick, NY.

Mayo Clinic: "Mayo Clinic named national site for Convalescent Plasma Expanded Access Program."

FDA: "Recommendations for Investigational COVID-19 Convalescent Plasma."

The Journal of the American Medical Association: "Treatment of 5 Critically Ill Patients With COVID-19 With Convalescent Plasma."

Press Medicine: "Treatment of Argentine hemorrhagic fever with convalescent's plasma. 4433 cases."

Proceedings of the National Academy of Sciences of the United States of America: "Effectiveness of convalescent plasma therapy in severe COVID-19 patients."

News release, FDA: "Coronavirus (COVID-19) Update: Daily Roundup, March 24, 2020."

News release, Stony Brook Medicine: "Volunteers Needed to Donate Blood Plasma to Help Hospitalized Patients with COVID-19," April 9, 2020.

News release, FDA: "Coronavirus (COVID-19) Update: FDA Coordinates National Effort to develop Blood-Related Therapies for COVID-19," April 3, 2020.

News release, Takeda: ''Global Plasma Leaders Collaborate to Accelerate Development of Potential COVID-19 Hyperimmune Therapy," April 6, 2020.

Open Forum Infectious Diseases: "High-Dose Intravenous Immuoglobulin as a Therapeutic Option for Deteriorating Patients With Coronavirus Disease 2019."


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