In the search for an effective treatment for COVID-19, an old method of fighting infectious diseases has recently resurfaced: transfusions with convalescent plasma. Plasma is a component of blood.
This method has a simple premise. The blood of people who have recovered from an infection contains antibodies. Antibodies are molecules that have learned to recognize and fight the pathogens, such as viruses, that have caused disease.
Doctors can separate plasma, one of the blood components that contain such antibodies, and administer it to people whose bodies are currently fighting an infectious disease. This can help their immune systems reject the pathogen more efficiently.
Recently, researchers and healthcare professionals have been looking into the possibility of using this method to treat people with COVID-19, the respiratory disease caused by the SARS-CoV-2 virus.
In the United States, a group of researchers and doctors from 57 institutions, including Johns Hopkins University, the Albert Einstein College of Medicine, and the Icahn School of Medicine at Mount Sinai, are investigating and applying convalescent plasma therapy for COVID-19.
This is a concerted initiative — called the “National COVID-19 Convalescent Plasma Project” — born after the publication of a viewpoint paper in The Journal of Clinical Investigation in March, 2020.
The paper argued for the potential merits of passive antibody therapy in the treatment of COVID-19. It was authored by immunologists Dr. Arturo Casadevall, chair of the Molecular Microbiology & Immunology Department at Johns Hopkins Bloomberg School of Public Health, and Dr. Liise-anne Pirofski, professor of Infectious Diseases in the Department of Medicine at the Albert Einstein College of Medicine.
To understand more about convalescent plasma therapy, its merits, its risks, and its current use in COVID-19 treatments, Medical News Today recently spoke to Dr. Casadevall.
Here is what he told us, alongside more information on the current state of convalescent plasma therapy.
A therapy ‘used for over 100 years’
So, where did the idea of using convalescent plasma, or passive antibody therapy, come from?
This notion was first introduced in the late 19th century when physiologist Emil von Behring and bacteriologist Kitasato Shibasaburou discovered that they could use antibodies present in serum — another blood component — to fight the bacterial infection diptheria.
Since then, doctors have used passive antibody therapy, on and off, at least since the 1930s to treat or prevent both bacterial and viral infections, including forms of pneumonia, meningitis, and measles.
When we asked him how the idea of using convalescent plasma therapy to treat COVID-19 came about, Dr. Casadevall told us: “I have worked on antibodies my entire life professional life […], and I knew that convalescent plasma — or sera […] — was being used for over 100 years.”
“In fact, the first Nobel Prize was given [to Behring] for the use of serum to treat diphtheria, so I knew the history.” This long history of successfully using this method against different infectious diseases suggested that it might also be effective against the disease caused by SARS-CoV-2.
“I knew that in epidemics when you don’t have a lot of things, […] the blood of those who recover can have antibodies that can be used [as treatment],” Dr. Casadevall explained.
“So it’s an old idea, it’s been around for a long time, and I think that my contribution was, in fact, to alert my friends, authorities, that this [therapy] could be used in this epidemic.”
Recent research has already shown that people who have contracted SARS-CoV-2 have developed antibodies that can react to the coronavirus.
“There [are] now multiple studies that have shown that when people recover from the virus, they have in their blood neutralizing antibodies that are able to kill the virus,” Dr. Casadevall also told MNT.
Although “[p]eople differ greatly in the amount of antibodies that they make — some make large amounts, some make small amounts — […] the good news is that most have [them],” he added.
Given the willingness of people who have recovered from COVID-19 to donate blood, the method seems feasible right now. In fact, some doctors are already using convalescent plasma therapy in some cases.