Feature

Can convalescent plasma treat COVID-19 patients?


 

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.

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 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.

Next Article: