Convalescent plasma, a soup of immune factors derived from the blood of recovered Covid-19 patients, had shown “an incredible rate of success” and would “save countless lives,” Trump said Aug 23. Yet more than four months later and with more than 330,000 U.S. coronavirus deaths reported since the pandemic began, the jury is still out how much the treatment benefits patients, if at all…

“It became evident in most people, even when it works, it’s not a Lazarus thing,” said Christopher Austin, director of the NIH’s National Center on Advancing Translational Sciences. “The effect was going to be smaller.”

The center is leading or involved in key clinical trials that will finally offer insight into convalescent plasma’s efficacy more than 100 years after it began being deployed during pandemics. The rationale behind the treatment is that the antibodies people develop after enduring a disease will help newly diagnosed patients recover.

“We do not know whether it works” against Covid-19, Austin said. “We all want to know the answer. I want to know the answer more than anybody. We have an obligation to future patients.”