Safety and efficacy of convalescent plasma therapy in severely and critically ill patients with COVID-19: a systematic review with meta-analysis

Background: The rapidly evolving coronavirus disease 2019 (COVID-19) has resulted in more than 24 million infections and 821 thousand deaths. However, a vaccine or specific drug is absent up to this date and more attention has been focused on the use of convalescent plasma (CP). Several articles have described the CP treatment for patients with SARS-CoV-2 infection. But a comprehensive systematic review with meta-analysis about the safety and efficacy of CP transfusion in SARS-CoV-2-infected patients has not been published. We conducted this study for a better understanding of the therapeutic significance of CP for patients with COVID-19. Results: A fixed-effect model (I(2)=0.0%) was used on the 9 articles for quantitative analysis showing that the mortality of patients with COVID-19 treated with or without CP was statistically significant (RR=0.57 [0.44-0.74]). Subgroup analysis showed that the severely ill patients benefited more from CP than the critically ill patients. Our study concluded that clinical improvement in severe COVID-19 cases were obvious. Adverse events were few and the effect of convalescent plasma on reducing viral load was apparent. Conclusions: Convalescent plasma therapy appears safe for COVID-19, and plasma treated patients have marked reductions in their serum viral loads and most are virus negative after transfusion. Patients with severe COVID-19 benefit more from the convalescent plasma transfusion than critical patients, and patients treated in early stage are more likely to survive. Methods: We reviewed the scientific literature from four databases published from December 8, 2019 to August 20, 2020. Statistical analyses were performed with STATA (version 15.1; Stata Corporation, College Station, TX, USA). The frequency with 95% confidence intervals (CI) was assessed using fixed effect model in analyzing the overall mortality and p <0.05 was considered statistically significant.