In a paper published Friday in the Journal of Clinical Investigation, Casadevall and a colleague, Dr. Liise-anne Pirofski, argued that collecting blood serum or plasma from previously infected people might be the best hope for treating severe cases of COVID-19, the disease caused by the virus, at least until a better treatment can be developed.

There’s some evidence from recent history that suggests the approach could work.

In 2003, doctors in China used plasma from recovered patients to treat 80 people suffering from the viral disease known as severe acute respiratory syndrome, or SARS — an earlier coronavirus — and found that the treatments were associated with improved outcomes and shorter hospital stays. In 2014, the World Health Organization published guidelines for using donated plasma to treat people infected with Ebola after the treatments showed promise.