Current View on Convalescent Plasma Therapy for COVID-19 Treatment: A Systematic Review and Prospective Meta-Analysis Based on Previous Respiratory Pandemics

Introduction: In addition to antiviral medication, Convalescent plasma therapy (CPT) has also been investigated for COVID-19 treatment. This study aimed to evaluate CPT potentials in COVID-19 treatment, by performing systematic review and meta-analysis of studies in COVID-19 and other similar viral respiratory diseases, including Severe Acute Respiratory Syndrome (SARS), Middle East Respiratory Syndrome (MERS) and Influenza. Method: PubMed and Google scholars database were used to collect publications up to June 6, 2020. We included all studies reported clinical outcomes of severe to critically ill viral respiratory diseases patients. Review/systematic review/meta-analysis and articles not written in English, ineligible for full-access were excluded. Meta-analysis used Mantel-Haezel Risk Ratio (RR) with 95% confidence interval for dichotomous data, while mean difference was calculated for continuous data with random effect model. Pooled analysis for individual patients data were performed with Inverse Variance Weighted Average using random effect model. The study is registered with PROSPERO, number CRD42020190579. Result: Our search identified 3,786 studies. Nineteen studies with 436 participants were included in the meta-analysis. Pooled analysis showed reduction of mortality [RR 0.46 (0.24, 0.86), z=2.41(p=0.02), I 2 =68% (p=0.003)] and higher number of discharged patients [RR 1.28 (1.12, 1.46), z=3.61 (p=0.0003), I 2 =73% (p=0.002)] in CPT groups. The mean time to discharge in COVID-19 patients after receiving CPT is 18.35 days. Possible CPT mechanism of action is due to its ability to immediately reduce viral titer [Mean diff -0.68(-0.94, -0.41), z=5.03 (p<0.00001), I 2 =0% (p=0.87)]. Adverse effect during transfusion was reported in 2 (2.2%) COVID-19 patients, and TRALI was identified in 2 (1.9%) SARS and MERS patients. Interpretation: CPT offers an easier and safer application during this pandemic, particularly when specific vaccines and medications are not yet available. Further investigation involving more patients and in combination with other treatment modalities are urgently needed. Funding: None Declaration of Interests: All authors have nothing to declare.