Association between convalescent plasma and the risk of mortality among patients with COVID-19: a meta-analysis.

Background: Convalescent plasma (CCP) has been used for treating some infectious diseases; however, the efficacy of CCP in coronavirus disease 2019 (COVID-19) remains controversial. The aim of this research was to assess the efficacy of CCP as an adjunctive treatment in COVID-19 patients. Methods: Four bibliographic databases and a preprint database were searched for potentially relevant articles. Mortality rates between patients treated with standard treatment and standard treatment with CCP were compared using a Z test. Results: A total of 1,937 patients treated with CCP and 3,405 patients without CCP retrieved from 12 studies were included. The risk of mortality was 1.92-fold higher in patients without CCP compared to patients treated with CCP (OR: 1.92; 95%CI: 1.33, 2.77; p=0.0005). In severe COVID-19 sub-group analysis, we found that patients without the CCP had a 1.32 times higher risk of mortality than those treated with the CCP (OR: 1.32; 95%CI: 1.09, 1.60; p=0.0040). Conclusions: CCP, as adjunctive therapy, reduces the mortality rate among COVID-19 patients.