It will be difficult “to find and diagnose them within that vanishingly small window,” said Dr. Ilan Schwartz, an infectious disease physician at the University of Alberta who wasn’t involved in the study. “The study looks solid, but not necessarily practical in the real world.”
Plasma has additional logistical hurdles, Dr. Titanji, of Emory University, said. The treatment is given as an intravenous infusion — a process that requires skilled hands — and patients need to be monitored afterward. That might be easier in long-term care facilities, but far tougher to accomplish for the general population, she said.
And plasma may not work as well as monoclonal antibody therapy — a synthetic concoction that’s manufactured en masse in the lab, rather than drawn from people’s blood, and focuses on just one or two types of antibodies at a time, instead of the entire slew produced naturally by the immune system. Two types of monoclonal antibody treatments have been authorized for emergency use in Covid patients.
But plasma does have some advantages over monoclonal antibody treatments, Dr. Polack pointed out.
Because monoclonal antibodies are synthetic and laborious to make, they carry a hefty price tag, sometimes costing thousands of dollars (although the U.S. government has paid for some doses upfront). The treatment’s limited supply chain, as well as unexpectedly low demand, has kept it out of the reach of many patients in need in the United States and abroad.
In countries like Argentina, plasma might be one of the best treatment options available, Dr. Polack said. Plasma infusions in Buenos Aires, he said, cost less than $200 a patient. “It’s more accessible, more inexpensive, more universal,” he said.
Even in the United States, plasma “is really the only game in town that’s broadly available in terms of antibody therapies,” Dr. Wang, of Stanford, said.
Rather than viewing monoclonal antibodies as an upgrade to convalescent plasma, “they each have a different place in the armamentarium,” Dr. Pirofski said. “Anything that has the capacity to control this virus is really an unbelievable advantage at this point.”