Researchers say that a decades-old approach could help fight SARS-CoV-2 infections. It involves collecting antibodies from the blood of people who have recovered from COVID-19.

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To fight COVID-19, researchers and doctors are trying an old technique: treating patients with antibodies from people who have recovered.

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The technique is called “passive antibody therapy.” It was used as early as the 1930s, and its premise is simple.

Medical practitioners collect blood from a person who has recovered from an infection and process it to separate the serum — the part of the blood that contains antibodies.

These are molecules that “learn” to fight specific pathogens — such as viruses — once they have been confronted with them.

Ultimately, the purpose is to inject a person with a current infection — or who is more susceptible to a SARS-CoV-2 infection — with the antibodies from someone who has just surpassed a similar infection, in order to help their immune system fight or prevent the disease.

In a new study paper featured in The Journal of Clinical Investigation, researchers from Johns Hopkins School of Public Health, in Baltimore, MD, and from the Albert Einstein College of Medicine, in New York, NY, argue that this technique could successfully be used to treat COVID-19.

“Deployment of this option requires no research or development,” says co-author Dr. Arturo Casadevall, an immunologist.

“It could be deployed within a couple of weeks, since it relies on standard blood-banking practices,” he suggests.

In their paper, Dr. Casadevall and Dr. Liise-anne Pirofski argue that passive antibody therapy could help prevent SARS-CoV-2 infections in those most at risk and help treat existing infections.

The researchers explain that with the collaboration of individuals who have recovered from COVID-19, this approach could be feasible.

Doctors could collect blood samples from convalescent volunteers, screen them for virus-neutralizing antibodies, isolate the sera from those samples, then clear them of any toxic particles and pathogens.

This would ultimately allow healthcare practitioners to provide injections of antibodies from people who have cleared the infection.

These antibodies, the study authors explain, could work in different ways, such as:

  • viral neutralization, in which the antibody attaches to the virus, killing it
  • antibody-dependent cellular cytotoxicity, in which the antibody stimulates a specialized immune cell to target the virus and attack its membrane, ultimately causing the virus to disintegrate
  • antibody-dependent cellular phagocytosis, in which the antibody stimulates a specialized immune cell to target the virus and “eat” it

While the researchers explain that using passive antibody therapy is within doctors’ current means — since it would only require readily available tools and technology — some challenges remain.

The foremost challenge is offering this treatment to people when it would be most effective.

Drs Casadevall and Pirofski note that “passive antibody therapy […] is more effective when used for prophylaxis [prevention] than for treatment of disease.”

And when healthcare providers do use this method to treat existing infection, it “is most effective when administered shortly after the onset of symptoms.” In other words, doctors would have to be very efficient in diagnosing the infection and providing the treatment.

Dr. Casadevall emphasizes:

“It’s all doable — but to get it done it requires effort organization, resources… and people who have recovered from the disease who can donate the blood.”

Still, he also notes that medical professionals are already stepping up to the challenge, with experts from Johns Hopkins already working on a viable strategy for implementing this approach.

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