Read on Twitter
As we think about convalescent plasma (CP), I thought it was worth looking at the actual data in other diseases. As best I can tell, the only actual trial showing efficacy for CP is in Argentine hemorrhagic fever, published in Lancet in 1979. It& #39;s an elegant study from 1974–1978
https://pubmed.ncbi.nlm.nih.gov/92624/ ">https://pubmed.ncbi.nlm.nih.gov/92624/&qu...
They blinded (using FFP as the control) and enrolled based on high clinical suspicion. Among the 217 enrolled, 188 had confirmed AHF. The money shot is this one: (p=0.0002 by Fisher& #39;s exact).
Nice. Turns out you really can do RCTs of convalescent plasma. But that& #39;s not the whole story--it turns out that there& #39;s a relapsing neurological syndrome that is dramatically more common in patients treated with CP. The one death in the CP arm actually happened as a result of
the neurological syndrome.
My take home--do the RCTs, and carefully watch for late safety signals. The more I read the more convinced I am that CP belongs in trials, not in ubiquitous clinical use.
