Effect of convalescent blood products for patients with severe acute respiratory infections of viral etiology: A systematic review and meta-analysis

OBJECTIVES: The aim of this study was to determine whether convalescent blood products (CBPs) offer a survival advantage for patients with severe acute respiratory infections of viral etiology. METHODS: Up-to-date trials were identified by the authors through searches of the MEDLINE, Embase, Cochrane Library, Web of Science, ClinicalTrials.gov, and medRxiv databases from inception up to September 14, 2020. Meta-analyses were performed using a random-effects model. RESULTS: According to the observational studies, patients who received CBPs showed a decline in all-cause mortality compared with patients who did not receive CBPs (odds ratio (OR) 0.36, 95% confidence interval (CI) 0.23–0.56; p < 0.00001). However, the randomized controlled trials (RCTs) showed no difference between the intervention group and the control group regarding all-cause mortality (OR 0.82, 95% CI 0.57–1.19; p = 0.30). The use of CBPs did not increase the risk of adverse events (OR 0.88, 95% CI 0.60–1.29; p = 0.51). Using CBPs earlier compared with using CBPs later was associated with a significant reduction in all-cause mortality (OR 0.18, 95% CI 0.08–0.40; p < 0.0001). CONCLUSIONS: Based on the outcomes of RCTs, CBPs may not decrease all-cause mortality. Furthermore, compared with later initiation of CBP therapy, earlier initiation of this therapy may decrease the rate of mortality.