Current views on the potentials of convalescent plasma therapy (CPT) as Coronavirus disease 2019 (COVID‐19) treatment: A systematic review and meta‐analysis based on recent studies and previous respiratory pandemics

Abstract

Summary Convalescent plasma therapy (CPT) has been investigated as a treatment for COVID‐19. This review evaluates CPT in COVID‐19 and other viral respiratory diseases, including severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS) and influenza. PubMed and Google scholar databases were used to collect eligible publications until 8 December 2020. Meta‐analysis used Mantel–Haenszel risk ratio (RR) with 95% confidence interval (CI) and pooled analysis for individual patient data with inverse variance weighted average. The study is registered at PROSPERO with the number of CRD4200270579. Forty‐four studies with 36,716 participants were included in the pooled analysis and 20 studies in the meta‐analysis. Meta‐analysis showed reduction of mortality (RR 0.57, 95% CI [0.43, 0.76], z = 3.86 [ p < 0.001], I 2 = 44% [ p = 0.03]) and higher number of discharged patients (RR 2.53, 95% CI [1.72, 3.72], z = 4.70 [ p < 0.001], I 2 = 3% [ p = 0.39]) in patients receiving CPT compared to standard care alone. A possible mechanism of action is prompt reduction in viral titre. Serious transfusion‐related adverse events were reported to be less than 1% of cases, suggesting the overall safety of CPT; nevertheless, the number of patients participating in the studies was still limited. It is also important to notice that in all the studies, the majority of patients were also given other medications, such as antivirals, antibiotics and corticosteroid; furthermore, randomized controlled studies involving more patients and in combination with other treatment modalities are urgently needed.

Safety and Efficacy of Convalescent Plasma in COVID-19: An Overview of Systematic Reviews

“…The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flow diagram is reported in Figure 1 . After the full texts were scrutinized against the inclusion and exclusion criteria, 29 SRs were included in the umbrella review [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 ] and 23 SRs were excluded [ 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , …”

“…Of the 29 SRs included in the overview, 26 were focused exclusively on COVID-19 [ 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 ], while three were focused on respiratory pandemics and on beta coronaviruses infections [ 10 , 19 , 30 ]. Two SRs [ 17 , 22 ] were a subgroup analysis of other reviews [ 16 , 21 ].…”

“…Twenty-eight SRs were focused on CP treatment of COVID-19, while one study [ 25 ] was focused on both CP prophylaxis and treatment. The majority of the SRs analyzed COVID-19 at any stage of disease severity, while four studies [ 10 , 30 , 36 , 38 ] were focused on more advanced (severe and/or critical) stages. Most SRs analyzed COVID-19 patients with no limitation of age, gender or ethnicity, while four SRs were focused only on adult (>18 years) COVID-19 patients [ 11 , 20 , 31 , 33 ].…”

Contemporary narrative review of treatment options for COVID‐19

“…63 Convalescent plasma was used in previous outbreak of other emerging infectious diseases, such as influenza, Ebola, SARS and MERS. 64,65 Given the theoretical effects, rapid availability and previous experience in treatment of other infectious diseases, convalescent plasma has been used to treat COVID-19 since the beginning of the outbreak. There have been numerous observational studies as well as 10 RCTs [66][67][68][69][70][71][72][73][74][75] comparing the effects and safety of convalescent plasma and placebo/standard care.…”

“…Convalescent plasma from recovered COVID‐19 patients is postulated to have neutralizing antibodies and provide passive immunity 63 . Convalescent plasma was used in previous outbreak of other emerging infectious diseases, such as influenza, Ebola, SARS and MERS 64,65 . Given the theoretical effects, rapid availability and previous experience in treatment of other infectious diseases, convalescent plasma has been used to treat COVID‐19 since the beginning of the outbreak.…”