The medical concept—known as “convalescent plasma” or “convalescent sera”—dates back to the early 20th century, and was used successfully in the past to counter epidemics including mumps and the measles. In a recent Wall Street Journal op-ed, Casadevall points to a notable case preventing a measles outbreak at a U.S. prep school in 1934.

Experts say a challenge of the technique is that precise timing is important in order to maximize the boost to a patient’s immunity. The treatment is not envisioned as a panacea to treating coronavirus, but a temporary measure that could help until stronger options such as vaccines are available.

“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,” Casadevall says. He adds that many people have stepped up to the plate at Hopkins and are already working to put this system in place.

Casadevall says he believes the solution “could do a lot locally” in the Baltimore region. He also noted that Johns Hopkins could become the Investigational New Drug (IND) center in the U.S. for this treatment, helping to administer it across states.

Learning more about how to use the sera most effectively will require further clinical studies. “We will learn new science from this calamity,” Casadevall says.