An old idea for fighting infections — an approach most physicians know about only from medical lore — is being revived as people wait for drugs and vaccines to thwart the novel coronavirus. If it works, the blood plasma of people who have recovered from covid-19 would be used to protect health-care workers and help sick people get well.
The possible therapy is based on a medical concept called “passive immunity.” People who recover from an infection develop antibodies that circulate in the blood and can neutralize the pathogen. Infusions of plasma — the clear liquid that remains when blood cells are removed — may increase people’s disease-fighting response to the virus, giving their immune systems an important boost.
…[However, clinicians] face regulatory, logistical and scientific challenges to set up a process that will ultimately be limited in how many people it can treat. Researchers must collect blood plasma from people after they’ve recovered, then test it to determine if it is likely to be potent against the disease and deliver it to patients.
The Food and Drug Administration announced [March 21] it was helping facilitate access to the experimental treatment, while underscoring the need to establish safety and effectiveness.