Efficacy and Safety of Convalescent Plasma Therapy for Severe COVID-19: A Multicenter, Randomized Controlled Trial

• • Clinical improvement at day 28 occurred in 51.9% of CP recipients versus 43.1% of controls (risk difference 8.8 percentage points; 95% CI -10.4 to 28.0; p=0.32), indicating no statistically significant benefit, yet a trend toward harm reduction. • • All-cause mortality at day 28 was 15.4% in the CP group versus 23.5% in the control group (hazard ratio 0.65; 95% CI 0.29 to 1.46; p=0.30), suggesting a potential mortality benefit that did not reach significance. • • Neutralizing antibody titers ≥1:80 at day 3 were achieved in 82.7% of CP recipients versus 21.6% of controls (p<0.001), confirming robust passive immunization. • • No significant differences in adverse events were observed between groups, supporting the safety profile of CP therapy in this critically ill population.