Objective  To evaluate the effectiveness and safety of convalescent plasma in treatment of patients with severe coronavirus disease 2019(COVID-19) by meta-analysis.

Methods  Databases such as EMBASE, PubMed, Web of Science, Cochrane Library, China National Knowledge Infrastructure(CNKI) and Chinese Biomedical Literature Database were searched to collect randomized controlled trials (RCTs) about convalescent plasma therapy for severe COVID-19, and the search deadline was December 1, 2021. The efficacy evaluation indexes included 28 d or 30 d mortality and discharge rate, and the safety evaluation index was the incidence of adverse events. A meta-analysis was performed by using RevMan 5.3 software.

Results  A total of 9 RCTs including 3 461 patients were enrolled in this meta-analysis, and the results showed that there were no significant differences in the 28 d or 30 d all-cause mortality (RR=0.94, 95%CI, 0.84 to 1.05, P=0.27), 28 d or 30 d discharge rate (RR=1.06, 95%CI, 0.95 to 1.19, P=0.28) and incidence of adverse events (RR=1.16, 95%CI, 0.71 to 1.88, P=0.55)between routine regimen and convalescent plasma.

Conclusion  meta-analysis of this study suggests that the convalescent plasma is safe in the treatment of patients with severe COVID-19, but it has no significant improvement in short-term mortality and discharge rate.