Plasma Therapy to Prevent Severe Covid-19 in Older Adults

To the Editor: Convalescent plasma therapy has shown a weak benefit in patients with severe or life-threatening Covid-19. However, when considering safety, 1 some have advocated its use beyond this limited scope. Libster and colleagues (Feb. 18 issue) 2 report positive results with the early administration of high-titer convalescent plasma against SARS-CoV-2 to mildly ill infected older adults. Although this randomized, controlled trial was limited in size (160 patients), it showed a 48% reduction in the relative risk of progression to severe respiratory disease. Given the extraordinary humoral responses to SARS-CoV-2 vaccines 3 and the paucity of donors with high-titer convalescent plasma (in . . .