Convalescent plasma therapy didn't help 52 seriously ill COVID-19 patients recover in the first known randomized study of its kind, although it was stopped early because of low enrollment.The study, published yesterday in JAMA, involved coronavirus patients with severe illness (respiratory distress and/or low oxygen levels) or life-threatening disease (shock, organ failure, or the need for mechanical ventilation) in seven medical centers in Wuhan, China, from Feb 14 to Apr 1, with final follow-up on Apr 28.The trial was stopped early because, owing to containment of the Wuhan outbreak, researchers were able to recruit only 103 of 200 patients needed to generate a clinically meaningful result.