Background: Convalescent plasma (CP) has been used successfully to treat many types of infectious diseases, and it has shown initial effects in the treatment of the emerging 2019 coronavirus disease (COVID-19). However, its curative effect and feasibility have yet to be confirmed by formal evaluation and well-designed clinical trials. To explore the effectiveness of treatment and predict the potential effect of CP for COVID-19, studies of different types of infectious diseases treated with CP were included in this systematic review and meta-analysis.
Methods: Related studies were obtained from databases and screened based on the inclusion criteria. The data quality was assessed, and the data were extracted and pooled for analysis.
Results: We included 40 studies on CP treatment for infectious diseases We found that CP treatment could reduce the risk of mortality with a low incidence of adverse events, promote the production of antibodies, show the decline in viral load, and shorten the disease course. A meta-analysis of 15 controlled studies showed that there was a significantly lower mortality rate in the group treated with CP (pooled OR = 0.32, 95% CI: 0.19-0.52, P < 0.001, I2 = 54%) than in the control groups. Studies were mostly of low or very low quality with a moderate or high risk of bias. The sources of clinical and methodological heterogeneity were identified. The exclusion of heterogeneity indicated that the results were stable. Conclusions: CP therapy has some curative effect and is well tolerated to treat infectious diseases. It is a potentially effective treatment for COVID-19.