Safety and efficacy of convalescent plasma as a therapy for SARS-CoV-2: A systematic review and meta-analysis

The safety and efficacy of convalescent plasma therapy (CPT) in SARS-CoV-2 is promising but intriguing due to heterogeneity of published studies. We conducted this systematic review and meta-analysis of convalescent plasma use in COVID-19 to identify its safety and efficacy.

We comprehensively searched the databases - PubMed, Web of Science, Embase, and the Cochrane Library for journal papers published between December 2019 and January 2021 about the use of CPT in SARS-CoV-2, and performed a meta-analysis using random effects models and assessed the quality of evidence using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach.

Of 1529 records, 11 studies were eligible (five RCTs, two nonrandomized intervention trials, three prospective observational, and one retrospective), and all were conducted in confirmed patients of SARS-CoV-2. Out of the 11 studies, four investigated the effect of CPT on mortality, three on symptom alleviation, five on duration of hospital stay, four on time to discharge, three on the effect on viral clearance, three on the improvement in antibody titers, two on oxygen requirement, and two on adverse events. The pooled estimate for relative risk of death from SARS-CoV-2 was no different after CPT than control (RR: 0.87, 95% CI: 0.69, 1.10), (p = 0.426) but the relative risk of clinical improvement of symptoms was better after CPT (RR: 1.61, 95% CI: 0.97. 2.70). There was earlier hospital discharge after CPT over control (RR: 1.49, 95% CI: 0.79, 2.80), improved viral clearance (RR: 1.95; 95% CI: 1.07, 3.53), and quicker detection of antibody titer (RR: 1.95; 95% CI: 1.07, 3.53). No difference was observed for adverse effects between CPT and control (RR: 0.92.; 95% CI: 0.63 1.35).

CPT appears to be a safe and promising treatment in moderate to severe SARS-CoV-2 leading to faster clinical improvement, reduced oxygen requirement, early hospital discharge, and quicker emergence of protective antibodies despite having no mortality benefit.