Blood From Covid-19 Survivors May Point the Way to a Cure

A 100-year-old way to beat disease could help researchers figure out how to harness the antibodies from earlier patients to help the newly infected.

Hospitals are gearing up to test if a century-old treatment used to fight off flu and measles outbreaks in the days before vaccines, and tried more recently against SARS and Ebola, just might work for COVID-19, too: using blood donated from patients who’ve recovered.

Doctors in China attempted the first COVID-19 treatments using what the history books call “convalescent serum” — today, known as donated plasma — from survivors of the new virus.

Now a network of U.S. hospitals is waiting on permission from the Food and Drug Administration begin large studies of the infusions both as a possible treatment for the sick and as vaccine-like temporary protection for people at high risk of infection.

There’s no guarantee it will work.

When a person gets infected by a particular germ, the body starts making specially designed proteins called antibodies to fight the infection. After the person recovers, those antibodies float in survivors’ blood — specifically plasma, the liquid part of blood — for months, even years.

One of the planned studies would test if giving infusions of survivors’ antibody-rich plasma to newly ill COVID-19 patients would boost their own body’s attempts to fight off the virus. To see if it works, researchers would measure if the treatment gave patients a better chance of living or reduced the need for breathing machines.

One caution: While regular plasma transfusions are a mainstay of medicine, very rarely they can cause a lung-damaging side effect.

What’s the history?

These plasma infusions were used most famously during the 1918 flu pandemic, and against numerous other infections, such as measles and bacterial pneumonia, before vaccines and modern medicines came along. Long-ago research is sketchy. But in the Journal of Clinical Investigation earlier this month, Casadevall and Pirofski cited evidence that 1918 flu patients given the infusions were less likely to die. And a 1935 medical report detailed how doctors stopped a measles outbreak from sweeping through a boarding school using “serum” from prior patients.

The old-fashioned approach still is dusted off every so often to tackle surprise outbreaks such as SARS in 2002, and in 2014 when Ebola survivors’ plasma was used to treat other patients during the West Africa epidemic. Even during those recent outbreaks, strict studies of the technique were not done, but Casadevall said there were clues that the plasma helped.