Convalescent plasma or hyperimmune immunoglobulin for people with COVID-19: a living systematic review

Systematic reviews should be at the heart of continuing medical education

Today, keeping up with the fast evolving evidence is more challenging than ever for practising physicians. A huge number of studies are published every day, and it is no longer possible to read all the relevant individual studies. Many physicians prefer attending continuing medical education (CME) to reading international scientific publications. Consequently, it is critical that CME is based on the best available evidence and presented in an unbiased manner free of conflicts of interest. Systematic reviews and Cochrane reviews in particular can thus provide a valuable resource of up-to-date and high-quality information on health care questions for CME providers. Of note, systematic reviews might become outdated quickly. Furthermore, some systematic reviews are fraught with limitations such as poor methodology and conduct or incomplete and misleading reporting. This article provides a brief overview of systematic reviews and Cochrane reviews, outlines how systematic reviews can be “kept alive” using today’s digital opportunities and points to several common problems of systematic reviews with suggestions for solutions.

Highly Neutralizing COVID-19 Convalescent Plasmas Potently Block SARS-CoV-2 Replication and Pneumonia in Syrian Hamsters

Despite various attempts to treat severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected patients with COVID-19 convalescent plasmas, neither appropriate approach nor clinical utility has been established. We examined the efficacy of administration of highly neutralizing COVID-19 convalescent plasma (hn-plasmas) and such plasma-derived IgG administration using the Syrian hamster COVID-19 model. Two hn-plasmas, which were in the best 1% of 340 neutralizing activity-determined convalescent plasmas, were intraperitoneally administered to SARS-CoV-2-infected hamsters, resulting in a significant reduction of viral titers in lungs by up to 32-fold compared to the viral titers in hamsters receiving control nonneutralizing plasma, while with two moderately neutralizing plasmas (mn-plasmas) administered, viral titer reduction was by up to 6-fold. IgG fractions purified from the two hn-plasmas also reduced viral titers in lungs more than those from the two mn-plasmas. The severity of lung lesions seen in hamsters receiving hn-plasmas was minimal to moderate as assessed using microcomputerized tomography, which histological examination confirmed. Western blotting revealed that all four COVID-19 convalescent plasmas variably contained antibodies against SARS-CoV-2 components, including the receptor-binding domain and S1 domain. The present data strongly suggest that administering potent neutralizing activity-confirmed COVID-19 convalescent plasmas would be efficacious in treating patients with COVID-19.

IMPORTANCE Convalescent plasmas obtained from patients who recovered from a specific infection have been used as agents to treat other patients infected with the very pathogen. To treat using convalescent plasmas, despite that more than 10 randomized controlled clinical trials have been conducted and more than 100 studies are currently ongoing, the effects of convalescent plasma against COVID-19 remained uncertain. On the other hand, certain COVID-19 vaccines have been shown to reduce the clinical COVID-19 onset by 94 to 95%, for which the elicited SARS-CoV-2-neutralizing antibodies are apparently directly responsible. Here, we demonstrate that highly neutralizing effect-confirmed convalescent plasmas significantly reduce the viral titers in the lung of SARS-CoV-2-infected Syrian hamsters and block the development of virally induced lung lesions. The present data provide a proof of concept that the presence of highly neutralizing antibody in COVID-19 convalescent plasmas is directly responsible for the reduction of viral replication and support the use of highly neutralizing antibody-containing plasmas in COVID-19 therapy with convalescent plasmas.

Effect of Convalescent Plasma on Organ Support-Free Days in Critically Ill Patients With COVID-19: A Randomized Clinical Trial

IMPORTANCE

The evidence for benefit of convalescent plasma for critically ill patients with COVID-19 is inconclusive.

OBJECTIVE

To determine whether convalescent plasma would improve outcomes for critically ill adults with COVID-19.

DESIGN, SETTING, AND PARTICIPANTS

The ongoing Randomized, Embedded, Multifactorial, Adaptive Platform Trial for Community-Acquired Pneumonia (REMAP-CAP) enrolled and randomized 4763 adults with suspected or confirmed COVID-19 between March 9, 2020, and January 18, 2021, within at least 1 domain; 2011 critically ill adults were randomized to open-label interventions in the immunoglobulin domain at 129 sites in 4 countries. Follow-up ended on April 19, 2021.

INTERVENTIONS

The immunoglobulin domain randomized participants to receive 2 units of high-titer, ABO-compatible convalescent plasma (total volume of 550 mL ± 150 mL) within 48 hours of randomization (n = 1084) or no convalescent plasma (n = 916).

MAIN OUTCOMES AND MEASURES

The primary ordinal end point was organ support-free days (days alive and free of intensive care unit-based organ support) up to day 21 (range, -1 to 21 days; patients who died were assigned -1 day). The primary analysis was an adjusted bayesian cumulative logistic model. Superiority was defined as the posterior probability of an odds ratio (OR) greater than 1 (threshold for trial conclusion of superiority >99%). Futility was defined as the posterior probability of an OR less than 1.2 (threshold for trial conclusion of futility >95%). An OR greater than 1 represented improved survival, more organ support-free days, or both. The prespecified secondary outcomes included in-hospital survival; 28-day survival; 90-day survival; respiratory support-free days; cardiovascular support-free days; progression to invasive mechanical ventilation, extracorporeal mechanical oxygenation, or death; intensive care unit length of stay; hospital length of stay; World Health Organization ordinal scale score at day 14; venous thromboembolic events at 90 days; and serious adverse events.

RESULTS

Among the 2011 participants who were randomized (median age, 61 [IQR, 52 to 70] years and 645/1998 [32.3%] women), 1990 (99%) completed the trial. The convalescent plasma intervention was stopped after the prespecified criterion for futility was met. The median number of organ support-free days was 0 (IQR, -1 to 16) in the convalescent plasma group and 3 (IQR, -1 to 16) in the no convalescent plasma group. The in-hospital mortality rate was 37.3% (401/1075) for the convalescent plasma group and 38.4% (347/904) for the no convalescent plasma group and the median number of days alive and free of organ support was 14 (IQR, 3 to 18) and 14 (IQR, 7 to 18), respectively. The median-adjusted OR was 0.97 (95% credible interval, 0.83 to 1.15) and the posterior probability of futility (OR <1.2) was 99.4% for the convalescent plasma group compared with the no convalescent plasma group. The treatment effects were consistent across the primary outcome and the 11 secondary outcomes. Serious adverse events were reported in 3.0% (32/1075) of participants in the convalescent plasma group and in 1.3% (12/905) of participants in the no convalescent plasma group.

CONCLUSIONS AND RELEVANCE

Among critically ill adults with confirmed COVID-19, treatment with 2 units of high-titer, ABO-compatible convalescent plasma had a low likelihood of providing improvement in the number of organ support-free days.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02735707.

Colchicine for the treatment of COVID-19

BACKGROUND

The development of severe coronavirus disease 2019 (COVID-19) and poor clinical outcomes are associated with hyperinflammation and a complex dysregulation of the immune response. Colchicine is an anti-inflammatory medicine and is thought to improve disease outcomes in COVID-19 through a wide range of anti-inflammatory mechanisms. Patients and healthcare systems need more and better treatment options for COVID-19 and a thorough understanding of the current body of evidence.

OBJECTIVES

To assess the effectiveness and safety of Colchicine as a treatment option for COVID-19 in comparison to an active comparator, placebo, or standard care alone in any setting, and to maintain the currency of the evidence, using a living systematic review approach.

SEARCH METHODS

We searched the Cochrane COVID-19 Study Register (comprising CENTRAL, MEDLINE (PubMed), Embase, ClinicalTrials.gov, WHO International Clinical Trials Registry Platform, and medRxiv), Web of Science (Science Citation Index Expanded and Emerging Sources Citation Index), and WHO COVID-19 Global literature on coronavirus disease to identify completed and ongoing studies without language restrictions to 21 May 2021.

SELECTION CRITERIA

We included randomised controlled trials evaluating colchicine for the treatment of people with COVID-19, irrespective of disease severity, age, sex, or ethnicity. We excluded studies investigating the prophylactic effects of colchicine for people without severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection but at high risk of SARS-CoV-2 exposure.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methodology. We used the Cochrane risk of bias tool (ROB 2) to assess bias in included studies and GRADE to rate the certainty of evidence for the following prioritised outcome categories considering people with moderate or severe COVID-19: all-cause mortality, worsening and improvement of clinical status, quality of life, adverse events, and serious adverse events and for people with asymptomatic infection or mild disease: all-cause mortality, admission to hospital or death, symptom resolution, duration to symptom resolution, quality of life, adverse events, serious adverse events.

MAIN RESULTS

We included three RCTs with 11,525 hospitalised participants (8002 male) and one RCT with 4488 (2067 male) non-hospitalised participants. Mean age of people treated in hospital was about 64 years, and was 55 years in the study with non-hospitalised participants. Further, we identified 17 ongoing studies and 11 studies completed or terminated, but without published results. Colchicine plus standard care versus standard care (plus/minus placebo) Treatment of hospitalised people with moderate to severe COVID-19 All-cause mortality: colchicine plus standard care probably results in little to no difference in all-cause mortality up to 28 days compared to standard care alone (risk ratio (RR) 1.00, 95% confidence interval (CI) 0.93 to 1.08; 2 RCTs, 11,445 participants; moderate-certainty evidence). Worsening of clinical status: colchicine plus standard care probably results in little to no difference in worsening of clinical status assessed as new need for invasive mechanical ventilation or death compared to standard care alone (RR 1.02, 95% CI 0.96 to 1.09; 2 RCTs, 10,916 participants; moderate-certainty evidence). Improvement of clinical status: colchicine plus standard care probably results in little to no difference in improvement of clinical status, assessed as number of participants discharged alive up to day 28 without clinical deterioration or death compared to standard care alone (RR 0.99, 95% CI 0.96 to 1.01; 1 RCT, 11,340 participants; moderate-certainty evidence). Quality of life, including fatigue and neurological status: we identified no studies reporting this outcome. Adverse events: the evidence is very uncertain about the effect of colchicine on adverse events compared to placebo (RR 1.00, 95% CI 0.56 to 1.78; 1 RCT, 72 participants; very low-certainty evidence). Serious adverse events: the evidence is very uncertain about the effect of colchicine plus standard care on serious adverse events compared to standard care alone (0 events observed in 1 RCT of 105 participants; very low-certainty evidence). Treatment of non-hospitalised people with asymptomatic SARS-CoV-2 infection or mild COVID-19 All-cause mortality: the evidence is uncertain about the effect of colchicine on all-cause mortality at 28 days (Peto odds ratio (OR) 0.57, 95% CI 0.20 to 1.62; 1 RCT, 4488 participants; low-certainty evidence). Admission to hospital or death within 28 days: colchicine probably slightly reduces the need for hospitalisation or death within 28 days compared to placebo (RR 0.80, 95% CI 0.62 to 1.03; 1 RCT, 4488 participants; moderate-certainty evidence). Symptom resolution: we identified no studies reporting this outcome. Quality of life, including fatigue and neurological status: we identified no studies reporting this outcome. Adverse events: the evidence is uncertain about the effect of colchicine on adverse events compared to placebo . Results are from one RCT reporting treatment-related events only in 4412 participants (low-certainty evidence). Serious adverse events: colchicine probably slightly reduces serious adverse events (RR 0.78, 95% CI 0.61 to 1.00; 1 RCT, 4412 participants; moderate-certainty evidence). Colchicine versus another active treatment (e.g. corticosteroids, anti-viral drugs, monoclonal antibodies) No studies evaluated this comparison. Different formulations, doses, or schedules of colchicine No studies assessed this.

AUTHORS' CONCLUSIONS

Based on the current evidence, in people hospitalised with moderate to severe COVID-19 the use of colchicine probably has little to no influence on mortality or clinical progression in comparison to placebo or standard care alone. We do not know whether colchicine increases the risk of (serious) adverse events. We are uncertain about the evidence of the effect of colchicine on all-cause mortality for people with asymptomatic infection or mild disease. However, colchicine probably results in a slight reduction of hospital admissions or deaths within 28 days, and the rate of serious adverse events compared with placebo. None of the studies reported data on quality of life or compared the benefits and harms of colchicine versus other drugs, or different dosages of colchicine. We identified 17 ongoing and 11 completed but not published RCTs, which we expect to incorporate in future versions of this review as their results become available. Editorial note: due to the living approach of this work, we monitor newly published results of RCTs on colchicine on a weekly basis and will update the review when the evidence or our certainty in the evidence changes.

Results of the CAPSID randomized trial for high-dose convalescent plasma in patients with severe COVID-19

BACKGROUNDCOVID-19 convalescent plasma (CCP) has been considered a treatment option for COVID-19. This trial assessed the efficacy of a neutralizing antibody containing high-dose CCP in hospitalized adults with COVID-19 requiring respiratory support or intensive care treatment.METHODSPatients (n = 105) were randomized 1:1 to either receive standard treatment and 3 units of CCP or standard treatment alone. Control group patients with progress on day 14 could cross over to the CCP group. The primary outcome was a dichotomous composite outcome of survival and no longer fulfilling criteria for severe COVID-19 on day 21.ResultsThe primary outcome occurred in 43.4% of patients in the CCP group and 32.7% in the control group (P = 0.32). The median time to clinical improvement was 26 days in the CCP group and 66 days in the control group (P = 0.27). The median time to discharge from the hospital was 31 days in the CCP group and 51 days in the control group (P = 0.24). In the subgroup that received a higher cumulative amount of neutralizing antibodies, the primary outcome occurred in 56.0% of the patients (vs. 32.1%), with significantly shorter intervals to clinical improvement (20 vs. 66 days, P < 0.05) and to hospital discharge (21 vs. 51 days, P = 0.03) and better survival (day-60 probability of survival 91.6% vs. 68.1%, P = 0.02) in comparison with the control group.ConclusionCCP added to standard treatment was not associated with a significant improvement in the primary and secondary outcomes. A predefined subgroup analysis showed a significant benefit of CCP among patients who received a larger amount of neutralizing antibodies.Trial registrationClinicalTrials.gov NCT04433910.FundingBundesministerium für Gesundheit (German Federal Ministry of Health): ZMVI1-2520COR802.

Rapid and Successful Implementation of a COVID-19 Convalescent Plasma Programme-The South African Experience

BACKGROUND

COVID-19 convalescent plasma (CCP) has been considered internationally as a treatment option for COVID-19. CCP refers to plasma collected from donors who have recovered from and made antibodies to SARS-CoV-2. To date, convalescent plasma has not been collected in South Africa. As other investigational therapies and vaccination were not widely accessible, there was an urgent need to implement a CCP manufacture programme to service South Africans.

METHODS

The South African National Blood Service and the Western Cape Blood Service implemented a CCP programme that included CCP collection, processing, testing and storage. CCP units were tested for SARS-CoV-2 Spike ELISA and neutralising antibodies and routine blood transfusion parameters. CCP units from previously pregnant females were tested for anti-HLA and anti-HNA antibodies.

RESULTS

A total of 987 CCP units were collected from 243 donors, with a median of three donations per donor. Half of the CCP units had neutralising antibody titres of >1:160. One CCP unit was positive on the TPHA serology. All CCP units tested for anti-HLA antibodies were positive.

CONCLUSION

Within three months of the first COVID-19 diagnosis in South Africa, a fully operational CCP programme was set up across South Africa. The infrastructure and skills implemented will likely benefit South Africans in this and future pandemics.

Convalescent Plasma for Patients Hospitalized With Coronavirus Disease 2019: A Meta-Analysis With Trial Sequential Analysis of Randomized Controlled Trials

Current evidence from randomized controlled trials (RCTs) and systematic reviews on the utility of convalescent plasma (CP) in patients with coronavirus disease 2019 (COVID-19) suggests a lack of benefit. We conducted an updated meta-analysis of RCTs with trial sequential analysis to investigate whether convalescent plasma is futile in reducing mortality in patients hospitalized with COVID-19. We searched 6 databases from December 1, 2019 to August 1, 2021 for RCTs comparing the use of CP with standard of care or transfusion of non-CP standard plasma in patients with COVID-19. The risk of bias was assessed using the Cochrane Risk-of-Bias 2 Tool. Random effects (DerSimonian and Laird) meta-analyses were conducted. The primary outcome was the aggregate risk for in-hospital mortality between both arms. We conducted a trial sequential analysis (TSA) based on the pooled relative risks (RRs) for in-hospital mortality. Secondary outcomes included the pooled RR for receipt of mechanical ventilation and mean difference in hospital length of stay. We included 18 RCTs (8702 CP, 7906 control). CP was not associated with a significant mortality benefit (RR: 0.95, 95%-CI: 0.86-1.04, P = .27, high certainty). Subgroup analysis did not find any significant differences (p_interaction = 0.30) between patients who received CP within 8 days of symptom onset (RR: 0.97, 95%-CI: 0.79-1.19, P = .80), or after 8 days (RR: 0.79, 95%-CI: 0.57-1.10, P = .16). TSA based on a RR reduction of 10% from a baseline mortality of 20% found that CP was not effective, with the pooled effect within the boundary for futility. CP did not significantly reduce the requirement for mechanical ventilation (RR: 1.00, 95%-CI: 0.91-1.10, P = .99, moderate certainty) or hospital length of stay (+1.32, 95%-CI: -1.86 to +4.52, P = .42, low certainty). CP does not improve relevant clinical outcomes in patients with COVID-19, especially in severe disease. The pooled effect of mortality was within the boundary of futility, suggesting the lack of benefit of CP in patients hospitalized with COVID-19.

The Effectiveness of Convalescent Plasma for the Treatment of Novel Corona Virus Disease 2019: A Systematic Review and Meta-Analysis

Background: Coronavirus disease 2019 (COVID-19), sweeping across the world, has created a worldwide pandemic. Effective treatments of COVID-19 are extremely urgent. Objective: To analyze the efficacy and safety of convalescent plasma (CCP) on patients with COVID-19. Methods: All the relevant studies were searched from PubMed, EMBASE,Cochrane library, Scopus, Web of Science, CBM, CNKI, Wan fang, VIP, Medrxiv, Biorxiv, and SSRN on July 19, 2021. PICOS criteria were as follows: (P) the study interests were human subjects with the infection of COVID-19; (I) the intervention of interest was CCP; (C) comparator treatments contained placebo, sham therapy, and standard treatment; (O) the primary outcome was mortality rates by the novel coronavirus. The secondary outcomes included the incidence of serious adverse events, the rate of ICU admission and mechanical ventilation (MV); the length of hospital stay; the duration of MV and ICU stay; the antibody levels, inflammatory factor levels, and viral loads. (S) Only randomized controlled trials (RCTs) of CCP were included. Subanalysis, quality assessment, sensitive analysis, and publication bias were conducted by two reviewers independently. Results: Sixteen RCTs were included and enrolled a total of 16,296 participants in this meta-analysis. The pooled data showed that no significant difference was observed in reducing the rate of overall mortality between CCP treatment group and placebo group (OR 0.96; 95% CI 0.90 to 1.03; p = 0.30; I 2 = 6%). According to the results of subgroup analysis, severe or critical patients with CCP showed significant difference in reducing the 28-day mortality of compared with placebo (OR 0.58, 95% CI 0.36 to 0.93, p = 0.02, I 2 = 0%). CCP groups have a significantly shorter duration of MV compared with the control group (weighted MD -1.00, 95% CI -1.86 to -0.14 d p = 0.02, I 2 = 0%). No significant difference was observed in the length of hospital stay, the duration of ICU, and the rate of ICU and MV. There is no conclusive evidence about the safety of CCP. Conclusion: Convalescent plasma can significantly reduce the 28-day mortality of severe or critical COVID-19 patients and the duration of MV. However, more evidence was needed to prove the safety of convalescent plasma.

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

Convalescent plasma (CP) from patients recovered from COVID-19 is one of the most studied anti-viral therapies against SARS-COV-2 infection. The aim of this study is to summarize the evidence from the available systematic reviews on the efficacy and safety of CP in COVID-19 through an overview of the published systematic reviews (SRs). A systematic literature search was conducted up to August 2021 in Embase, PubMed, Web of Science, Cochrane and Medrxiv databases to identify systematic reviews focusing on CP use in COVID-19. Two review authors independently evaluated reviews for inclusion, extracted data and assessed quality of evidence using AMSTAR (A Measurement Tool to Assess Reviews) and GRADE tools. The following outcomes were analyzed: mortality, viral clearance, clinical improvement, length of hospital stay, adverse reactions. In addition, where possible, subgroup analyses were performed according to study design (e.g., RCTs vs. non-RCTs), CP neutralizing antibody titer and timing of administration, and disease severity. The methodological quality of included studies was assessed using the checklist for systematic reviews AMSTAR-2 and the GRADE assessment. Overall, 29 SRs met the inclusion criteria based on 53 unique primary studies (17 RCT and 36 non-RCT). Limitations to the methodological quality of reviews most commonly related to absence of a protocol (11/29) and funding sources of primary studies (27/29). Of the 89 analyses on which GRADE judgements were made, effect estimates were judged to be of high/moderate certainty in four analyses, moderate in 38, low in 38, very low in nine. Despite the variability in the certainty of the evidence, mostly related to the risk of bias and inconsistency, the results of this umbrella review highlight a mortality reduction in CP over standard therapy when administered early and at high titer, without increased adverse reactions.

Convalescent plasma for hospitalized patients with COVID-19: an open-label, randomized controlled trial

The efficacy of convalescent plasma for coronavirus disease 2019 (COVID-19) is unclear. Although most randomized controlled trials have shown negative results, uncontrolled studies have suggested that the antibody content could influence patient outcomes. We conducted an open-label, randomized controlled trial of convalescent plasma for adults with COVID-19 receiving oxygen within 12 d of respiratory symptom onset (NCT04348656). Patients were allocated 2:1 to 500 ml of convalescent plasma or standard of care. The composite primary outcome was intubation or death by 30 d. Exploratory analyses of the effect of convalescent plasma antibodies on the primary outcome was assessed by logistic regression. The trial was terminated at 78% of planned enrollment after meeting stopping criteria for futility. In total, 940 patients were randomized, and 921 patients were included in the intention-to-treat analysis. Intubation or death occurred in 199/614 (32.4%) patients in the convalescent plasma arm and 86/307 (28.0%) patients in the standard of care arm—relative risk (RR) = 1.16 (95% confidence interval (CI) 0.94–1.43, P = 0.18). Patients in the convalescent plasma arm had more serious adverse events (33.4% versus 26.4%; RR = 1.27, 95% CI 1.02–1.57, P = 0.034). The antibody content significantly modulated the therapeutic effect of convalescent plasma. In multivariate analysis, each standardized log increase in neutralization or antibody-dependent cellular cytotoxicity independently reduced the potential harmful effect of plasma (odds ratio (OR) = 0.74, 95% CI 0.57–0.95 and OR = 0.66, 95% CI 0.50–0.87, respectively), whereas IgG against the full transmembrane spike protein increased it (OR = 1.53, 95% CI 1.14–2.05). Convalescent plasma did not reduce the risk of intubation or death at 30 d in hospitalized patients with COVID-19. Transfusion of convalescent plasma with unfavorable antibody profiles could be associated with worse clinical outcomes compared to standard care.

A randomized trial in patients hospitalized with COVID-19 showed no benefit and potentially increased harm associated with the use of convalescent plasma, with subgroup analyses suggesting that the antibody profile in donor plasma is critical in determining clinical outcomes.

SARS-CoV-2-neutralising monoclonal antibodies for treatment of COVID-19

BACKGROUND

Monoclonal antibodies (mAbs) are laboratory-produced molecules derived from the B cells of an infected host. They are being investigated as a potential therapy for coronavirus disease 2019 (COVID-19).

OBJECTIVES

To assess the effectiveness and safety of SARS-CoV-2-neutralising mAbs for treating patients with COVID-19, compared to an active comparator, placebo, or no intervention. To maintain the currency of the evidence, we will use a living systematic review approach. A secondary objective is to track newly developed SARS-CoV-2-targeting mAbs from first tests in humans onwards.  SEARCH METHODS: We searched MEDLINE, Embase, the Cochrane COVID-19 Study Register, and three other databases on 17 June 2021. We also checked references, searched citations, and contacted study authors to identify additional studies. Between submission and publication, we conducted a shortened randomised controlled trial (RCT)-only search on 30 July 2021.

SELECTION CRITERIA

We included studies that evaluated SARS-CoV-2-neutralising mAbs, alone or combined, compared to an active comparator, placebo, or no intervention, to treat people with COVID-19. We excluded studies on prophylactic use of SARS-CoV-2-neutralising mAbs.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed search results, extracted data, and assessed risk of bias using the Cochrane risk of bias tool (RoB2). Prioritised outcomes were all-cause mortality by days 30 and 60, clinical progression, quality of life, admission to hospital, adverse events (AEs), and serious adverse events (SAEs). We rated the certainty of evidence using GRADE.

MAIN RESULTS

We identified six RCTs that provided results from 17,495 participants with planned completion dates between July 2021 and December 2031. Target sample sizes varied from 1020 to 10,000 participants. Average age was 42 to 53 years across four studies of non-hospitalised participants, and 61 years in two studies of hospitalised participants. Non-hospitalised individuals with COVID-19 Four studies evaluated single agents bamlanivimab (N = 465), sotrovimab (N = 868), regdanvimab (N = 307), and combinations of bamlanivimab/etesevimab (N = 1035), and casirivimab/imdevimab (N = 799). We did not identify data for mortality at 60 days or quality of life. Our certainty of the evidence is low for all outcomes due to too few events (very serious imprecision).  Bamlanivimab compared to placebo No deaths occurred in the study by day 29. There were nine people admitted to hospital by day 29 out of 156 in the placebo group compared with one out of 101 in the group treated with 0.7 g bamlanivimab (risk ratio (RR) 0.17, 95% confidence interval (CI) 0.02 to 1.33), 2 from 107 in the group treated with 2.8 g (RR 0.32, 95% CI 0.07 to 1.47) and 2 from 101 in the group treated with 7.0 g (RR 0.34, 95% CI 0.08 to 1.56). Treatment with 0.7 g, 2.8 g and 7.0 g bamlanivimab may have similar rates of AEs as placebo (RR 0.99, 95% CI 0.66 to 1.50; RR 0.90, 95% CI 0.59 to 1.38; RR 0.81, 95% CI 0.52 to 1.27). The effect on SAEs is uncertain. Clinical progression/improvement of symptoms or development of severe symptoms were not reported. Bamlanivimab/etesevimab compared to placebo There were 10 deaths in the placebo group and none in bamlanivimab/etesevimab group by day 30 (RR 0.05, 95% CI 0.00 to 0.81). Bamlanivimab/etesevimab may decrease hospital admission by day 29 (RR 0.30, 95% CI 0.16 to 0.59), may result in a slight increase in any grade AEs (RR 1.15, 95% CI 0.83 to 1.59) and may increase SAEs (RR 1.40, 95% CI 0.45 to 4.37). Clinical progression/improvement of symptoms or development of severe symptoms were not reported. Casirivimab/imdevimab compared to placebo Casirivimab/imdevimab may reduce hospital admissions or death (2.4 g: RR 0.43, 95% CI 0.08 to 2.19; 8.0 g: RR 0.21, 95% CI 0.02 to 1.79). We are uncertain of the effect on grades 3-4 AEs (2.4 g: RR 0.76, 95% CI 0.17 to 3.37; 8.0 g: RR 0.50, 95% CI 0.09 to 2.73) and SAEs (2.4 g: RR 0.68, 95% CI 0.19 to 2.37; 8.0 g: RR 0.34, 95% CI 0.07 to 1.65). Mortality by day 30 and clinical progression/improvement of symptoms or development of severe symptoms were not reported. Sotrovimab compared to placebo We are uncertain whether sotrovimab has an effect on mortality (RR 0.33, 95% CI 0.01 to 8.18) and invasive mechanical ventilation (IMV) requirement or death (RR 0.14, 95% CI 0.01 to 2.76). Treatment with sotrovimab may reduce the number of participants with oxygen requirement (RR 0.11, 95 % CI 0.02 to 0.45), hospital admission or death by day 30 (RR 0.14, 95% CI 0.04 to 0.48), grades 3-4 AEs (RR 0.26, 95% CI 0.12 to 0.60), SAEs (RR 0.27, 95% CI 0.12 to 0.63) and may have little or no effect on any grade AEs (RR 0.87, 95% CI 0.66 to 1.16).  Regdanvimab compared to placebo Treatment with either dose (40 or 80 mg/kg) compared with placebo may decrease hospital admissions or death (RR 0.45, 95% CI 0.14 to 1.42; RR 0.56, 95% CI 0.19 to 1.60, 206 participants), but may increase grades 3-4 AEs (RR 2.62, 95% CI 0.52 to 13.12; RR 2.00, 95% CI 0.37 to 10.70). 80 mg/kg may reduce any grade AEs (RR 0.79, 95% CI 0.52 to 1.22) but 40 mg/kg may have little to no effect (RR 0.96, 95% CI 0.64 to 1.43). There were too few events to allow meaningful judgment for the outcomes mortality by 30 days, IMV requirement, and SAEs.  Hospitalised individuals with COVID-19 Two studies evaluating bamlanivimab as a single agent (N = 314) and casirivimab/imdevimab as a combination therapy (N = 9785) were included.   Bamlanivimab compared to placebo  We are uncertain whether bamlanivimab has an effect on mortality by day 30 (RR 1.39, 95% CI 0.40 to 4.83) and SAEs by day 28 (RR 0.93, 95% CI 0.27 to 3.14). Bamlanivimab may have little to no effect on time to hospital discharge (HR 0.97, 95% CI 0.78 to 1.20) and mortality by day 90 (HR 1.09, 95% CI 0.49 to 2.43). The effect of bamlanivimab on the development of severe symptoms at day 5 (RR 1.17, 95% CI 0.75 to 1.85) is uncertain. Bamlanivimab may increase grades 3-4 AEs at day 28 (RR 1.27, 95% CI 0.81 to 1.98). We assessed the evidence as low certainty for all outcomes due to serious imprecision, and very low certainty for severe symptoms because of additional concerns about indirectness. Casirivimab/imdevimab with usual care compared to usual care alone Treatment with casirivimab/imdevimab compared to usual care probably has little or no effect on mortality by day 30 (RR 0.94, 95% CI 0.87 to 1.02), IMV requirement or death (RR 0.96, 95% CI 0.90 to 1.04), nor alive at hospital discharge by day 30 (RR 1.01, 95% CI 0.98 to 1.04). We assessed the evidence as moderate certainty due to study limitations (lack of blinding). AEs and SAEs were not reported.  AUTHORS' CONCLUSIONS: The evidence for each comparison is based on single studies. None of these measured quality of life. Our certainty in the evidence for all non-hospitalised individuals is low, and for hospitalised individuals is very low to moderate. We consider the current evidence insufficient to draw meaningful conclusions regarding treatment with SARS-CoV-2-neutralising mAbs. Further studies and long-term data from the existing studies are needed to confirm or refute these initial findings, and to understand how the emergence of SARS-CoV-2 variants may impact the effectiveness of SARS-CoV-2-neutralising mAbs. Publication of the 36 ongoing studies may resolve uncertainties about the effectiveness and safety of SARS-CoV-2-neutralising mAbs for the treatment of COVID-19 and possible subgroup differences.

[COVID-19: Critical appraisal of the evidence]

We present the summary of a critical appraisal document of the available evidence on COVID-19, developed with a clinical practice guide format following GRADE methodology. The document tries to provide answers to a series of structured clinical questions, with an explicit definition of the population, intervention/exposure, comparison and outcome, and a rating of the clinical relevance of the outcome measures. We conducted a systematic review of the literature to answer the questions, grouped into six chapters: epidemiology, clinical practice, diagnosis, treatment, prevention, and vaccination. We assessed the risk of bias of the selected studies with standard instruments (RoB-2, ROBINS-I, QUADAS and Newcastle-Ottawa). We constructed evidence tables and, when necessary and possible, meta-analysis of the of the most relevant outcome measures. We followed the GRADE system to synthesize the evidence, assessing its quality, and, when appropriate, giving recommendations, rated according to the quality of the evidence, the values and preferences, the balance between benefits, risks and costs, equity and feasibility.

Convalescent plasma is of limited clinical benefit in critically ill patients with coronavirus disease-2019: a cohort study

Background

Recently, convalescent plasma (CP) transfusion was employed for severe or critically ill patients with coronavirus disease-2019. However, the benefits of CP for patients with different conditions are still in debate. To contribute clinical evidence of CP on critically ill patients, we analyze the characteristics and outcomes of patients with or without CP transfusion.

Methods

In this cohort study, 14 patients received CP transfusion based on the standard treatments, whereas the other 10 patients received standard treatments as control. Clinical characteristics and outcomes were analyzed. The cumulative survival rate was calculated by Kaplan–Meier survival analysis.

Results

Data analysis was performed on 24 patients (male/female: 15/9) with a median age of 64.0 (44.5–74.5) years. Transient fever was reported in one patient. The cumulative mortality was 21% (3/14) in patients receiving CP transfusion during a 28-day observation, whereas one dead case (1/10) was reported in the control group. No significant difference was detected between groups in 28-day mortality (P = 0.615) and radiological alleviation of lung lesions (P = 0.085).

Conclusion

In our current study, CP transfusion was clinically safe based on the safety profile; however, the clinical benefit was not significant in critically ill patients with more comorbidities at the late stage of disease during a 28-day observation.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-03028-5.

Interventions for palliative symptom control in COVID-19 patients

BACKGROUND

Individuals dying of coronavirus disease 2019 (COVID-19) may experience distressing symptoms such as breathlessness or delirium. Palliative symptom management can alleviate symptoms and improve the quality of life of patients. Various treatment options such as opioids or breathing techniques have been discussed for use in COVID-19 patients. However, guidance on symptom management of COVID-19 patients in palliative care has often been derived from clinical experiences and guidelines for the treatment of patients with other illnesses. An understanding of the effectiveness of pharmacological and non-pharmacological palliative interventions to manage specific symptoms of COVID-19 patients is required.

OBJECTIVES

To assess the efficacy and safety of pharmacological and non-pharmacological interventions for palliative symptom control in individuals with COVID-19.

SEARCH METHODS

We searched the Cochrane COVID-19 Study Register (including Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (PubMed), Embase, ClinicalTrials.gov, World Health Organization International Clinical Trials Registry Platform (WHO ICTRP), medRxiv); Web of Science Core Collection (Science Citation Index Expanded, Emerging Sources); CINAHL; WHO COVID-19 Global literature on coronavirus disease; and COAP Living Evidence on COVID-19 to identify completed and ongoing studies without language restrictions until 23 March 2021. We screened the reference lists of relevant review articles and current treatment guidelines for further literature.

SELECTION CRITERIA

We followed standard Cochrane methodology as outlined in the Cochrane Handbook for Systematic Reviews of Interventions. We included studies evaluating palliative symptom management for individuals with a confirmed diagnosis of COVID-19 receiving interventions for palliative symptom control, with no restrictions regarding comorbidities, age, gender, or ethnicity. Interventions comprised pharmacological as well as non-pharmacological treatment (e.g. acupressure, physical therapy, relaxation, or breathing techniques). We searched for the following types of studies: randomized controlled trials (RCT), quasi-RCTs, controlled clinical trials, controlled before-after studies, interrupted time series (with comparison group), prospective cohort studies, retrospective cohort studies, (nested) case-control studies, and cross-sectional studies. We searched for studies comparing pharmacological and non-pharmacological interventions for palliative symptom control with standard care. We excluded studies evaluating palliative interventions for symptoms caused by other terminal illnesses. If studies enrolled populations with or exposed to multiple diseases, we would only include these if the authors provided subgroup data for individuals with COVID-19. We excluded studies investigating interventions for symptom control in a curative setting, for example patients receiving life-prolonging therapies such as invasive ventilation.  DATA COLLECTION AND ANALYSIS: We used a modified version of the Newcastle Ottawa Scale for non-randomized studies of interventions (NRSIs) to assess bias in the included studies. We included the following outcomes: symptom relief (primary outcome); quality of life; symptom burden; satisfaction of patients, caregivers, and relatives; serious adverse events; and grade 3 to 4 adverse events. We rated the certainty of evidence using the GRADE approach.  As meta-analysis was not possible, we used tabulation to synthesize the studies and histograms to display the outcomes.  MAIN RESULTS: Overall, we identified four uncontrolled retrospective cohort studies investigating pharmacological interventions for palliative symptom control in hospitalized patients and patients in nursing homes. None of the studies included a comparator. We rated the risk of bias high across all studies. We rated the certainty of the evidence as very low for the primary outcome symptom relief, downgrading mainly for high risk of bias due to confounding and unblinded outcome assessors. Pharmacological interventions for palliative symptom control We identified four uncontrolled retrospective cohort studies (five references) investigating pharmacological interventions for palliative symptom control. Two references used the same register to form their cohorts, and study investigators confirmed a partial overlap of participants. We therefore do not know the exact number of participants, but individual reports included 61 to 2105 participants. Participants received multimodal pharmacological interventions: opioids, neuroleptics, anticholinergics, and benzodiazepines for relieving dyspnea (breathlessness), delirium, anxiety, pain, audible upper airway secretions, respiratory secretions, nausea, cough, and unspecified symptoms.  Primary outcome: symptom relief All identified studies reported this outcome. For all symptoms (dyspnea, delirium, anxiety, pain, audible upper airway secretions, respiratory secretions, nausea, cough, and unspecified symptoms), a majority of interventions were rated as completely or partially effective by outcome assessors (treating clinicians or nursing staff). Interventions used in the studies were opioids, neuroleptics, anticholinergics, and benzodiazepines.  We are very uncertain about the effect of pharmacological interventions on symptom relief (very low-certainty evidence). The initial rating of the certainty of evidence was low since we only identified uncontrolled NRSIs. Our main reason for downgrading the certainty of evidence was high risk of bias due to confounding and unblinded outcome assessors. We therefore did not find evidence to confidently support or refute whether pharmacological interventions may be effective for palliative symptom relief in COVID-19 patients. Secondary outcomes We planned to include the following outcomes: quality of life; symptom burden; satisfaction of patients, caregivers, and relatives; serious adverse events; and grade 3 to 4 adverse events. We did not find any data for these outcomes, or any other information on the efficacy and safety of used interventions. Non-pharmacological interventions for palliative symptom control None of the identified studies used non-pharmacological interventions for palliative symptom control.

AUTHORS' CONCLUSIONS

We found very low certainty evidence for the efficacy of pharmacological interventions for palliative symptom relief in COVID-19 patients. We found no evidence on the safety of pharmacological interventions or efficacy and safety of non-pharmacological interventions for palliative symptom control in COVID-19 patients. The evidence presented here has no specific implications for palliative symptom control in COVID-19 patients because we cannot draw any conclusions about the effectiveness or safety based on the identified evidence. More evidence is needed to guide clinicians, nursing staff, and caregivers when treating symptoms of COVID-19 patients at the end of life. Specifically, future studies ought to investigate palliative symptom control in prospectively registered studies, using an active-controlled setting, assess patient-reported outcomes, and clearly define interventions. The publication of the results of ongoing studies will necessitate an update of this review. The conclusions of an updated review could differ from those of the present review and may allow for a better judgement regarding pharmacological and non-pharmacological interventions for palliative symptom control in COVID-19 patients.

Systemic corticosteroids for the treatment of COVID-19

BACKGROUND

Systemic corticosteroids are used to treat people with COVID-19 because they counter hyper-inflammation. Existing evidence syntheses suggest a slight benefit on mortality. So far, systemic corticosteroids are one of the few treatment options for COVID-19. Nonetheless, size of effect, certainty of the evidence, optimal therapy regimen, and selection of patients who are likely to benefit most are factors that remain to be evaluated.

OBJECTIVES

To assess whether systemic corticosteroids are effective and safe in the treatment of people with COVID-19, and to keep up to date with the evolving evidence base using a living systematic review approach.

SEARCH METHODS

We searched the Cochrane COVID-19 Study Register (which includes PubMed, Embase, CENTRAL, ClinicalTrials.gov, WHO ICTRP, and medRxiv), Web of Science (Science Citation Index, Emerging Citation Index), and the WHO COVID-19 Global literature on coronavirus disease to identify completed and ongoing studies to 16 April 2021.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that evaluated systemic corticosteroids for people with COVID-19, irrespective of disease severity, participant age, gender or ethnicity.  We included any type or dose of systemic corticosteroids. We included the following comparisons: systemic corticosteroids plus standard care versus standard care (plus/minus placebo), dose comparisons, timing comparisons (early versus late), different types of corticosteroids and systemic corticosteroids versus other active substances.  We excluded studies that included populations with other coronavirus diseases (severe acute respiratory syndrome or Middle East respiratory syndrome), corticosteroids in combination with other active substances versus standard care, topical or inhaled corticosteroids, and corticosteroids for long-COVID treatment.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methodology. To assess the risk of bias in included studies, we used the Cochrane 'Risk of bias' 2 tool for RCTs. We rated the certainty of evidence using the GRADE approach for the following outcomes: all-cause mortality, ventilator-free days, new need for invasive mechanical ventilation, quality of life, serious adverse events, adverse events, and hospital-acquired infections.

MAIN RESULTS

We included 11 RCTs in 8075 participants, of whom 7041 (87%) originated from high-income countries. A total of 3072 participants were randomised to corticosteroid arms and the majority received dexamethasone (n = 2322). We also identified 42 ongoing studies and 16 studies reported as being completed or terminated in a study registry, but without results yet.  Hospitalised individuals with a confirmed or suspected diagnosis of symptomatic COVID-19 Systemic corticosteroids plus standard care versus standard care plus/minus placebo  We included 10 RCTs (7989 participants), one of which did not report any of our pre-specified outcomes and thus our analysis included outcome data from nine studies.  All-cause mortality (at longest follow-up available): systemic corticosteroids plus standard care probably reduce all-cause mortality slightly in people with COVID-19 compared to standard care alone (median 28 days: risk difference of 30 in 1000 participants fewer than the control group rate of 275 in 1000 participants; risk ratio (RR) 0.89, 95% confidence interval (CI) 0.80 to 1.00; 9 RCTs, 7930 participants; moderate-certainty evidence).  Ventilator-free days: corticosteroids may increase ventilator-free days (MD 2.6 days more than control group rate of 4 days, 95% CI 0.67 to 4.53; 1 RCT, 299 participants; low-certainty evidence). Ventilator-free days have inherent limitations as a composite endpoint and should be interpreted with caution.  New need for invasive ventilation: the evidence is of very low certainty. Because of high risk of bias arising from deaths that occurred before ventilation we are uncertain about the size and direction of the effects. Consequently, we did not perform analysis beyond the presentation of descriptive statistics.  Quality of life/neurological outcome: no data were available. Serious adverse events: we included data on two RCTs (678 participants) that evaluated systemic corticosteroids compared to standard care (plus/minus placebo); for adverse events and hospital-acquired infections, we included data on five RCTs (660 participants). Because of high risk of bias, heterogeneous definitions, and underreporting we are uncertain about the size and direction of the effects. Consequently, we did not perform analysis beyond the presentation of descriptive statistics (very low-certainty evidence).    Different types, dosages or timing of systemic corticosteroids  We identified one study that compared methylprednisolone with dexamethasone. The evidence for mortality and new need for invasive mechanical ventilation is very low certainty due to the small number of participants (n = 86). No data were available for the other outcomes. We did not identify comparisons of different dosages or timing. Outpatients with asymptomatic or mild disease Currently, there are no studies published in populations with asymptomatic infection or mild disease.

AUTHORS' CONCLUSIONS

Moderate-certainty evidence shows that systemic corticosteroids probably slightly reduce all-cause mortality in people hospitalised because of symptomatic COVID-19. Low-certainty evidence suggests that there may also be a reduction in ventilator-free days. Since we are unable to  adjust for the impact of early death on subsequent endpoints, the findings for ventilation outcomes and harms have limited applicability to inform treatment decisions. Currently, there is no evidence for asymptomatic or mild disease (non-hospitalised participants).  There is an urgent need for good-quality evidence for specific subgroups of disease severity, for which we propose level of respiratory support at randomisation. This applies to the comparison or subgroups of different types and doses of corticosteroids, too. Outcomes apart from mortality should be measured and analysed appropriately taking into account confounding through death if applicable.  We identified 42 ongoing and 16 completed but not published RCTs in trials registries suggesting possible changes of effect estimates and certainty of the evidence in the future. Most ongoing studies target people who need respiratory support at baseline. With the living approach of this review, we will continue to update our search and include eligible trials and published data.

SARS-CoV-2 neutralising antibody testing in Europe: towards harmonisation of neutralising antibody titres for better use of convalescent plasma and comparability of trial data

We compared the performance of SARS-CoV-2 neutralising antibody testing between 12 European laboratories involved in convalescent plasma trials. Raw titres differed almost 100-fold differences between laboratories when blind-testing 15 plasma samples. Calibration of titres in relation to the reference reagent and standard curve obtained by testing a dilution series reduced the inter-laboratory variability ca 10-fold. The harmonisation of neutralising antibody quantification is a vital step towards determining the protective and therapeutic levels of neutralising antibodies.

Convalescent plasma or hyperimmune immunoglobulin for people with COVID-19: a living systematic review

BACKGROUND

Convalescent plasma and hyperimmune immunoglobulin may reduce mortality in patients with viral respiratory diseases, and are being investigated as potential therapies for coronavirus disease 2019 (COVID-19). A thorough understanding of the current body of evidence regarding benefits and risks of these interventions is required.  OBJECTIVES: Using a living systematic review approach, to assess whether convalescent plasma or hyperimmune immunoglobulin transfusion is effective and safe in the treatment of people with COVID-19; and to maintain the currency of the evidence.

SEARCH METHODS

To identify completed and ongoing studies, we searched the World Health Organization (WHO) COVID-19 Global literature on coronavirus disease Research Database, MEDLINE, Embase, the Cochrane COVID-19 Study Register, the Epistemonikos COVID-19 L*OVE Platform, and trial registries. Searches were done on 17 March 2021.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) evaluating convalescent plasma or hyperimmune immunoglobulin for COVID-19, irrespective of disease severity, age, gender or ethnicity. For safety assessments, we also included non-controlled non-randomised studies of interventions (NRSIs) if 500 or more participants were included. We excluded studies that included populations with other coronavirus diseases (severe acute respiratory syndrome (SARS) or Middle East respiratory syndrome (MERS)), as well as studies evaluating standard immunoglobulin.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methodology. To assess bias in included studies, we used the Cochrane 'Risk of Bias 2' tool for RCTs, and for NRSIs, the assessment criteria for observational studies, provided by Cochrane Childhood Cancer. We rated the certainty of evidence, using the GRADE approach, for the following outcomes: all-cause mortality, improvement and worsening of clinical status (for individuals with moderate to severe disease), development of severe clinical COVID-19 symptoms (for individuals with asymptomatic or mild disease), quality of life (including fatigue and functional independence), grade 3 or 4 adverse events, and serious adverse events.

MAIN RESULTS

We included 13 studies (12 RCTs, 1 NRSI) with 48,509 participants, of whom 41,880 received convalescent plasma. We did not identify any completed studies evaluating hyperimmune immunoglobulin. We identified a further 100 ongoing studies evaluating convalescent plasma or hyperimmune immunoglobulin, and 33 studies reporting as being completed or terminated. Individuals with a confirmed diagnosis of COVID-19 and moderate to severe disease Eleven RCTs and one NRSI investigated the use of convalescent plasma for 48,349 participants with moderate to severe disease. Nine RCTs compared convalescent plasma to placebo treatment or standard care alone, and two compared convalescent plasma to standard plasma (results not included in abstract). Effectiveness of convalescent plasma We included data on nine RCTs (12,875 participants) to assess the effectiveness of convalescent plasma compared to placebo or standard care alone.  Convalescent plasma does not reduce all-cause mortality at up to day 28 (risk ratio (RR) 0.98, 95% confidence interval (CI) 0.92 to 1.05; 7 RCTs, 12,646 participants; high-certainty evidence). It has little to no impact on clinical improvement for all participants when assessed by liberation from respiratory support (RR not estimable; 8 RCTs, 12,682 participants; high-certainty evidence). It has little to no impact on the chance of being weaned or liberated from invasive mechanical ventilation for the subgroup of participants requiring invasive mechanical ventilation at baseline (RR 1.04, 95% CI 0.57 to 1.93; 2 RCTs, 630 participants; low-certainty evidence). It does not reduce the need for invasive mechanical ventilation (RR 0.98, 95% CI 0.89 to 1.08; 4 RCTs, 11,765 participants; high-certainty evidence). We did not identify any subgroup differences.  We did not identify any studies reporting quality of life, and therefore, do not know whether convalescent plasma has any impact on quality of life. One RCT assessed resolution of fatigue on day 7, but we are very uncertain about the effect (RR 1.21, 95% CI 1.02 to 1.42; 309 participants; very low-certainty evidence).  Safety of convalescent plasma We included results from eight RCTs, and one NRSI, to assess the safety of convalescent plasma. Some of the RCTs reported on safety data only for the convalescent plasma group.  We are uncertain whether convalescent plasma increases or reduces the risk of grade 3 and 4 adverse events (RR 0.90, 95% CI 0.58 to 1.41; 4 RCTs, 905 participants; low-certainty evidence), and serious adverse events (RR 1.24, 95% CI 0.81 to 1.90; 2 RCTs, 414 participants; low-certainty evidence).  A summary of reported events of the NRSI (reporting safety data for 20,000 of 35,322 transfused participants), and four RCTs reporting safety data only for transfused participants (6125 participants) are included in the full text. Individuals with a confirmed diagnosis of SARS-CoV-2 infection and asymptomatic or mild disease We identified one RCT reporting on 160 participants, comparing convalescent plasma to placebo treatment (saline).  Effectiveness of convalescent plasma We are very uncertain about the effect of convalescent plasma on all-cause mortality (RR 0.50, 95% CI 0.09 to 2.65; very low-certainty evidence). We are uncertain about the effect of convalescent plasma on developing severe clinical COVID-19 symptoms (RR not estimable; low-certainty evidence).  We identified no study reporting quality of life.  Safety of convalescent plasma We do not know whether convalescent plasma is associated with a higher risk of grade 3 or 4 adverse events (very low-certainty evidence), or serious adverse events (very low-certainty evidence). This is a living systematic review. We search weekly for new evidence and update the review when we identify relevant new evidence. Please refer to the Cochrane Database of Systematic Reviews for the current status of this review.

AUTHORS' CONCLUSIONS

We have high certainty in the evidence that convalescent plasma for the treatment of individuals with moderate to severe disease does not reduce mortality and has little to no impact on measures of clinical improvement. We are uncertain about the adverse effects of convalescent plasma. While major efforts to conduct research on COVID-19 are being made, heterogeneous reporting of outcomes is still problematic. There are 100 ongoing studies and 33 studies reporting in a study registry as being completed or terminated. Publication of ongoing studies might resolve some of the uncertainties around hyperimmune immunoglobulin therapy for people with any disease severity, and convalescent plasma therapy for people with asymptomatic or mild disease.