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1.
COVID-19 Convalescent Plasma Outpatient Therapy to Prevent Outpatient Hospitalization: A Meta-analysis of Individual Participant Data From Five Randomized Trials
Levine AC, Fukuta Y, Huaman MA, Ou J, Meisenberg BR, Patel B, Paxton JH, Hanley DF, Rijnders BJ, Gharbharan A, et al
Clinical infectious diseases : an official publication of the Infectious Diseases Society of America. 2023
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Editor's Choice
Abstract
BACKGROUND Outpatient monoclonal antibodies are no longer effective and antiviral treatments for COVID-19 disease remain largely unavailable in many countries worldwide. Although treatment with COVID-19 convalescent plasma is promising, clinical trials among outpatients have shown mixed results. METHODS We conducted an individual participant data meta-analysis from outpatient trials to assess the overall risk reduction for all-cause hospitalizations by day 28 in transfused participants. Relevant trials were identified by searching MEDLINE, Embase, MedRxiv, World Health Organization, Cochrane Library, and Web of Science from January 2020 to September 2022. RESULTS Five included studies from four countries enrolled and transfused 2,620 adult patients. Comorbidities were present in 1,795 (69%). The virus neutralizing antibody dilutional titer levels ranged from 8 to 14,580 in diverse assays. 160 (12.2%) of 1315 control patients were hospitalized, versus 111 (8.5%) of 1305 COVID-19 convalescent plasma treated patients, yielding a 3.7% (95%CI: 1.3%-6.0%; p=.001) absolute risk reduction and 30.1% relative risk reduction for all-cause hospitalization. The hospitalization reduction was greatest in those with both early transfusion and high titer with a 7.6% absolute risk reduction (95%CI: 4.0%-11.1%; p=.0001) accompanied by at 51.4% relative risk reduction. No significant reduction in hospitalization was seen with treatment > 5 days after symptom onset or in those receiving COVID-19 convalescent plasma with antibody titers below the median titer. CONCLUSIONS Among outpatients with COVID-19, treatment with COVID-19 convalescent plasma reduced the rate of all-cause hospitalization and may be most effective when given within 5 days of symptom onset and when antibody titer is higher.
PICO Summary
Population
Adult COVID-19 outpatients (5 studies, n= 2,620).
Intervention
Intravenous COVID-19 convalescent plasma (CCP) transfusion (n= 1,305).
Comparison
Non-convalescent plasma or normal saline (n= 1,315).
Outcome
The virus neutralizing antibody dilutional titre levels ranged from 8 to 14,580 in diverse assays. 160 (12.2%) of 1,315 control patients were hospitalized, versus 111 (8.5%) of 1,305 COVID-19 convalescent plasma treated patients, yielding a 3.7% (95% CI: 1.3% - 6.0%) absolute risk reduction and 30.1% relative risk reduction for all-cause hospitalization. The hospitalization reduction was greatest in those with both early transfusion and high titre with a 7.6% absolute risk reduction (95% CI: 4.0% - 11.1%) accompanied by at 51.4% relative risk reduction. No significant reduction in hospitalization was seen with treatment > 5 days after symptom onset or in those receiving COVID-19 convalescent plasma with antibody titres below the median titre.
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Plasmapheresis to remove amyloid fibrin(ogen) particles for treating the post-COVID-19 condition
Fox, T., Hunt, B. J., Ariens, R. A., Towers, G. J., Lever, R., Garner, P., Kuehn, R.
The Cochrane database of systematic reviews. 2023;7(7):Cd015775
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Editor's Choice
Abstract
BACKGROUND The post-COVID-19 condition (PCC) consists of a wide array of symptoms including fatigue and impaired daily living. People seek a wide variety of approaches to help them recover. A new belief, arising from a few laboratory studies, is that 'microclots' cause the symptoms of PCC. This belief has been extended outside these studies, suggesting that to recover people need plasmapheresis (an expensive process where blood is filtered outside the body). We appraised the laboratory studies, and it was clear that the term 'microclots' is incorrect to describe the phenomenon being described. The particles are amyloid and include fibrin(ogen); amyloid is not a part of a thrombus which is a mix of fibrin mesh and platelets. Initial acute COVID-19 infection is associated with clotting abnormalities; this review concerns amyloid fibrin(ogen) particles in PCC only. We have reported here our appraisal of laboratory studies investigating the presence of amyloid fibrin(ogen) particles in PCC, and of evidence that plasmapheresis may be an effective therapy to remove amyloid fibrin(ogen) particles for treating PCC. OBJECTIVES Laboratory studies review To summarize and appraise the research reports on amyloid fibrin(ogen) particles related to PCC. Randomized controlled trials review To assess the evidence of the safety and efficacy of plasmapheresis to remove amyloid fibrin(ogen) particles in individuals with PCC from randomized controlled trials. SEARCH METHODS Laboratory studies review We searched for all relevant laboratory studies up to 27 October 2022 using a comprehensive search strategy which included the search terms 'COVID', 'amyloid', 'fibrin', 'fibrinogen'. Randomized controlled trials review We searched the following databases on 21 October 2022: Cochrane COVID-19 Study Register; MEDLINE (Ovid); Embase (Ovid); and BIOSIS Previews (Web of Science). We also searched the WHO International Clinical Trials Registry Platform and ClinicalTrials.gov for trials in progress. SELECTION CRITERIA Laboratory studies review Laboratory studies that investigate the presence of amyloid fibrin(ogen) particles in plasma samples from patients with PCC were eligible. This included studies with or without controls. Randomized controlled trials review Studies were eligible if they were of randomized controlled design and investigated the effectiveness or safety of plasmapheresis for removing amyloid fibrin(ogen) particles for treating PCC. DATA COLLECTION AND ANALYSIS Two review authors applied study inclusion criteria to identify eligible studies and extracted data. Laboratory studies review We assessed the risk of bias of included studies using pre-developed methods for laboratory studies. We planned to perform synthesis without meta-analysis (SWiM) as described in our protocol. Randomized controlled trials review We planned that if we identified any eligible studies, we would assess risk of bias and report results with 95% confidence intervals. The primary outcome was recovery, measured using the Post-COVID-19 Functional Status Scale (absence of symptoms related to the illness, ability to do usual daily activities, and a return to a previous state of health and mind). MAIN RESULTS Laboratory studies review We identified five laboratory studies. Amyloid fibrin(ogen) particles were identified in participants across all studies, including those with PCC, healthy individuals, and those with diabetes. The results of three studies were based on visual images of amyloid fibrin(ogen) particles, which did not quantify the amount or size of the particles identified. Formal risk of bias assessment showed concerns in how the studies were conducted and reported. This means the results were insufficient to support the belief that amyloid fibrin(ogen) particles are associated with PCC, or to determine whether there is a difference in the amount or size of amyloid fibrin(ogen) particles in the plasma of people with PCC compared to healthy controls. Randomized controlled trials review We identified no trials meeting our inclusion criteria. AUTHORS' CONCLUSIONS In the absence of reliable research showing that amyloid fibrin(ogen) particles contribute to the pathophysiology of PCC, there is no rationale for plasmapheresis to remove amyloid fibrin(ogen) particles in PCC. Plasmapheresis for this indication should not be used outside the context of a well-conducted randomized controlled trial.
PICO Summary
Population
Any person diagnosed with post‐COVID‐19 condition (PCC), (5 laboratory studies).
Intervention
Plasmapheresis performed with the intention of removing amyloid fibrin(ogen) particles.
Comparison
Placebo or standard of care.
Outcome
No randomised controlled trials or ongoing trials where patients with PCC had undergone plasmapheresis with the intention of removing amyloid fibrin(ogen) particles were found. Five laboratory studies that assessed whether amyloid fibrin(ogen) particles were present in the blood of patients with post‐COVID‐19 condition were included. Amyloid fibrin(ogen) particles were identified in participants across the included studies, including those with PCC, healthy individuals, and those with diabetes. The results of three studies were based on visual images of amyloid fibrin(ogen) particles, which did not quantify the amount or size of the particles identified. Formal risk of bias assessment showed concerns in how the studies were conducted and reported. This means the results were insufficient to support the belief that amyloid fibrin(ogen) particles are associated with PCC, or to determine whether there is a difference in the amount or size of amyloid fibrin(ogen) particles in the plasma of people with PCC compared to healthy controls.
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3.
Convalescent plasma for people with COVID-19: a living systematic review
Iannizzi C, Chai KL, Piechotta V, Valk SJ, Kimber C, Monsef I, Wood EM, Lamikanra AA, Roberts DJ, McQuilten Z, et al
The Cochrane database of systematic reviews. 2023;5(5):Cd013600
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Editor's Choice
Abstract
BACKGROUND Convalescent plasma may reduce mortality in patients with viral respiratory diseases, and is being investigated as a potential therapy for coronavirus disease 2019 (COVID-19). A thorough understanding of the current body of evidence regarding benefits and risks of this intervention is required. OBJECTIVES To assess the effectiveness and safety of convalescent plasma transfusion in the treatment of people with COVID-19; and to maintain the currency of the evidence using a living systematic review approach. 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, Cochrane COVID-19 Study Register, and the Epistemonikos COVID-19 L*OVE Platform. We searched monthly until 03 March 2022. SELECTION CRITERIA We included randomised controlled trials (RCTs) evaluating convalescent plasma for COVID-19, irrespective of disease severity, age, gender or ethnicity. 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 RoB 2. We used the GRADE approach to rate the certainty of evidence for the following outcomes: all-cause mortality at up to day 28, worsening and improvement of clinical status (for individuals with moderate to severe disease), hospital admission or death, COVID-19 symptoms resolution (for individuals with mild disease), quality of life, grade 3 or 4 adverse events, and serious adverse events. MAIN RESULTS In this fourth review update version, we included 33 RCTs with 24,861 participants, of whom 11,432 received convalescent plasma. Of these, nine studies are single-centre studies and 24 are multi-centre studies. Fourteen studies took place in America, eight in Europe, three in South-East Asia, two in Africa, two in western Pacific and three in eastern Mediterranean regions and one in multiple regions. We identified a further 49 ongoing studies evaluating convalescent plasma, and 33 studies reporting as being completed. Individuals with a confirmed diagnosis of COVID-19 and moderate to severe disease 29 RCTs investigated the use of convalescent plasma for 22,728 participants with moderate to severe disease. 23 RCTs with 22,020 participants compared convalescent plasma to placebo or standard care alone, five compared to standard plasma and one compared to human immunoglobulin. We evaluate subgroups on detection of antibodies detection, symptom onset, country income groups and several co-morbidities in the full text. Convalescent plasma versus 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 1.03; 220 per 1000; 21 RCTs, 19,021 participants; high-certainty evidence). It has little to no impact on need for invasive mechanical ventilation, or death (RR 1.03, 95% CI 0.97 to 1.11; 296 per 1000; 6 RCTs, 14,477 participants; high-certainty evidence) and has no impact on whether participants are discharged from hospital (RR 1.00, 95% CI 0.97 to 1.02; 665 per 1000; 6 RCTs, 12,721 participants; high-certainty evidence). Convalescent plasma may have little to no impact on quality of life (MD 1.00, 95% CI -2.14 to 4.14; 1 RCT, 483 participants; low-certainty evidence). Convalescent plasma may have little to no impact on the risk of grades 3 and 4 adverse events (RR 1.17, 95% CI 0.96 to 1.42; 212 per 1000; 6 RCTs, 2392 participants; low-certainty evidence). It has probably little to no effect on the risk of serious adverse events (RR 1.14, 95% CI 0.91 to 1.44; 135 per 1000; 6 RCTs, 3901 participants; moderate-certainty evidence). Convalescent plasma versus standard plasma We are uncertain whether convalescent plasma reduces or increases all-cause mortality at up to day 28 (RR 0.73, 95% CI 0.45 to 1.19; 129 per 1000; 4 RCTs, 484 participants; very low-certainty evidence). We are uncertain whether convalescent plasma reduces or increases the need for invasive mechanical ventilation, or death (RR 5.59, 95% CI 0.29 to 108.38; 311 per 1000; 1 study, 34 participants; very low-certainty evidence) and whether it reduces or increases the risk of serious adverse events (RR 0.80, 95% CI 0.55 to 1.15; 236 per 1000; 3 RCTs, 327 participants; very low-certainty evidence). We did not identify any study reporting other key outcomes. Convalescent plasma versus human immunoglobulin Convalescent plasma may have little to no effect on all-cause mortality at up to day 28 (RR 1.07, 95% CI 0.76 to 1.50; 464 per 1000; 1 study, 190 participants; low-certainty evidence). We did not identify any study reporting other key outcomes. Individuals with a confirmed diagnosis of SARS-CoV-2 infection and mild disease We identified two RCTs reporting on 536 participants, comparing convalescent plasma to placebo or standard care alone, and two RCTs reporting on 1597 participants with mild disease, comparing convalescent plasma to standard plasma. Convalescent plasma versus placebo or standard care alone We are uncertain whether convalescent plasma reduces all-cause mortality at up to day 28 (odds ratio (OR) 0.36, 95% CI 0.09 to 1.46; 8 per 1000; 2 RCTs, 536 participants; very low-certainty evidence). It may have little to no effect on admission to hospital or death within 28 days (RR 1.05, 95% CI 0.60 to 1.84; 117 per 1000; 1 RCT, 376 participants; low-certainty evidence), on time to COVID-19 symptom resolution (hazard ratio (HR) 1.05, 95% CI 0.85 to 1.30; 483 per 1000; 1 RCT, 376 participants; low-certainty evidence), on the risk of grades 3 and 4 adverse events (RR 1.29, 95% CI 0.75 to 2.19; 144 per 1000; 1 RCT, 376 participants; low-certainty evidence) and the risk of serious adverse events (RR 1.14, 95% CI 0.66 to 1.94; 133 per 1000; 1 RCT, 376 participants; low-certainty evidence). We did not identify any study reporting other key outcomes. Convalescent plasma versus standard plasma We are uncertain whether convalescent plasma reduces all-cause mortality at up to day 28 (OR 0.30, 95% CI 0.05 to 1.75; 2 per 1000; 2 RCTs, 1597 participants; very low-certainty evidence). It probably reduces admission to hospital or death within 28 days (RR 0.49, 95% CI 0.31 to 0.75; 36 per 1000; 2 RCTs, 1595 participants; moderate-certainty evidence). Convalescent plasma may have little to no effect on initial symptom resolution at up to day 28 (RR 1.12, 95% CI 0.98 to 1.27; 1 RCT, 416 participants; low-certainty evidence). We did not identify any study reporting other key outcomes. This is a living systematic review. We search monthly for new evidence and update the review when we identify relevant new evidence. AUTHORS' CONCLUSIONS For the comparison of convalescent plasma versus placebo or standard care alone, our certainty in the evidence that convalescent plasma for individuals with moderate to severe disease does not reduce mortality and has little to no impact on clinical improvement or worsening is high. It probably has little to no effect on SAEs. For individuals with mild disease, we have very-low to low certainty evidence for most primary outcomes and moderate certainty for hospital admission or death. There are 49 ongoing studies, and 33 studies reported as complete in a trials registry. Publication of ongoing studies might resolve some of the uncertainties around convalescent plasma therapy for people with asymptomatic or mild disease.
PICO Summary
Population
People of any age with COVID-19 (33 randomised controlled trials (RCTs) n= 24,861).
Intervention
Convalescent plasma (n= 11,432).
Comparison
Standard plasma, human immunoglobulin, placebo or standard care alone.
Outcome
This living systematic review fourth review update version included 33 RCTs, of these 9 were single‐centre studies and 24 were multi‐centre studies. The authors identified 49 ongoing studies. Individuals with a confirmed diagnosis of COVID‐19 and moderate to severe disease: 23 RCTs compared convalescent plasma to placebo or standard care alone; 5 RCTs compared convalescent plasma to standard plasma, and 1 RCT compared convalescent plasma to human immunoglobulin. Individuals with a confirmed diagnosis of SARS‐CoV‐2 infection and mild disease: 2 RCTs compared convalescent plasma to placebo or standard care alone, and 2 RCTs compared convalescent plasma to standard plasma. When comparing convalescent plasma vs. placebo or standard care alone, authors’ certainty in the evidence that convalescent plasma for individuals with moderate to severe disease does not reduce mortality and has little to no impact on clinical improvement or worsening is high. For individuals with mild disease, the authors have very-low to low certainty evidence for most primary outcomes and moderate certainty for hospital admission or death.
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4.
Convalescent plasma for people with COVID-19: a living systematic review
Iannizzi C, Chai KL, Piechotta V, Valk SJ, Kimber C, Monsef I, Wood EM, Lamikanra AA, Roberts DJ, McQuilten Z, et al
The Cochrane database of systematic reviews. 2023;2(2):Cd013600
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Editor's Choice
Abstract
BACKGROUND Convalescent plasma may reduce mortality in patients with viral respiratory diseases, and is being investigated as a potential therapy for coronavirus disease 2019 (COVID-19). A thorough understanding of the current body of evidence regarding benefits and risks of this intervention is required. OBJECTIVES To assess the effectiveness and safety of convalescent plasma transfusion in the treatment of people with COVID-19; and to maintain the currency of the evidence using a living systematic review approach. 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, Cochrane COVID-19 Study Register, and the Epistemonikos COVID-19 L*OVE Platform. We searched monthly until 03 March 2022. SELECTION CRITERIA We included randomised controlled trials (RCTs) evaluating convalescent plasma for COVID-19, irrespective of disease severity, age, gender or ethnicity. 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 RoB 2. We used the GRADE approach to rate the certainty of evidence for the following outcomes: all-cause mortality at up to day 28, worsening and improvement of clinical status (for individuals with moderate to severe disease), hospital admission or death, COVID-19 symptoms resolution (for individuals with mild disease), quality of life, grade 3 or 4 adverse events, and serious adverse events. MAIN RESULTS In this fourth review update version, we included 33 RCTs with 24,861 participants, of whom 11,432 received convalescent plasma. Of these, nine studies are single-centre studies and 24 are multi-centre studies. Fourteen studies took place in America, eight in Europe, three in South-East Asia, two in Africa, two in western Pacific and three in eastern Mediterranean regions and one in multiple regions. We identified a further 49 ongoing studies evaluating convalescent plasma, and 33 studies reporting as being completed. Individuals with a confirmed diagnosis of COVID-19 and moderate to severe disease 29 RCTs investigated the use of convalescent plasma for 22,728 participants with moderate to severe disease. 23 RCTs with 22,020 participants compared convalescent plasma to placebo or standard care alone, five compared to standard plasma and one compared to human immunoglobulin. We evaluate subgroups on detection of antibodies detection, symptom onset, country income groups and several co-morbidities in the full text. Convalescent plasma versus 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 1.03; 220 per 1000; 21 RCTs, 19,021 participants; high-certainty evidence). It has little to no impact on need for invasive mechanical ventilation, or death (RR 1.03, 95% CI 0.97 to 1.11; 296 per 1000; 6 RCTs, 14,477 participants; high-certainty evidence) and has no impact on whether participants are discharged from hospital (RR 1.00, 95% CI 0.97 to 1.02; 665 per 1000; 6 RCTs, 12,721 participants; high-certainty evidence). Convalescent plasma may have little to no impact on quality of life (MD 1.00, 95% CI -2.14 to 4.14; 1 RCT, 483 participants; low-certainty evidence). Convalescent plasma may have little to no impact on the risk of grades 3 and 4 adverse events (RR 1.17, 95% CI 0.96 to 1.42; 212 per 1000; 6 RCTs, 2392 participants; low-certainty evidence). It has probably little to no effect on the risk of serious adverse events (RR 1.14, 95% CI 0.91 to 1.44; 135 per 1000; 6 RCTs, 3901 participants; moderate-certainty evidence). Convalescent plasma versus standard plasma We are uncertain whether convalescent plasma reduces or increases all-cause mortality at up to day 28 (RR 0.73, 95% CI 0.45 to 1.19; 129 per 1000; 4 RCTs, 484 participants; very low-certainty evidence). We are uncertain whether convalescent plasma reduces or increases the need for invasive mechanical ventilation, or death (RR 5.59, 95% CI 0.29 to 108.38; 311 per 1000; 1 study, 34 participants; very low-certainty evidence) and whether it reduces or increases the risk of serious adverse events (RR 0.80, 95% CI 0.55 to 1.15; 236 per 1000; 3 RCTs, 327 participants; very low-certainty evidence). We did not identify any study reporting other key outcomes. Convalescent plasma versus human immunoglobulin Convalescent plasma may have little to no effect on all-cause mortality at up to day 28 (RR 1.07, 95% CI 0.76 to 1.50; 464 per 1000; 1 study, 190 participants; low-certainty evidence). We did not identify any study reporting other key outcomes. Individuals with a confirmed diagnosis of SARS-CoV-2 infection and mild disease We identified two RCTs reporting on 536 participants, comparing convalescent plasma to placebo or standard care alone, and two RCTs reporting on 1597 participants with mild disease, comparing convalescent plasma to standard plasma. Convalescent plasma versus placebo or standard care alone We are uncertain whether convalescent plasma reduces all-cause mortality at up to day 28 (odds ratio (OR) 0.36, 95% CI 0.09 to 1.46; 8 per 1000; 2 RCTs, 536 participants; very low-certainty evidence). It may have little to no effect on admission to hospital or death within 28 days (RR 1.05, 95% CI 0.60 to 1.84; 117 per 1000; 1 RCT, 376 participants; low-certainty evidence), on time to COVID-19 symptom resolution (hazard ratio (HR) 1.05, 95% CI 0.85 to 1.30; 483 per 1000; 1 RCT, 376 participants; low-certainty evidence), on the risk of grades 3 and 4 adverse events (RR 1.29, 95% CI 0.75 to 2.19; 144 per 1000; 1 RCT, 376 participants; low-certainty evidence) and the risk of serious adverse events (RR 1.14, 95% CI 0.66 to 1.94; 133 per 1000; 1 RCT, 376 participants; low-certainty evidence). We did not identify any study reporting other key outcomes. Convalescent plasma versus standard plasma We are uncertain whether convalescent plasma reduces all-cause mortality at up to day 28 (OR 0.30, 95% CI 0.05 to 1.75; 2 per 1000; 2 RCTs, 1597 participants; very low-certainty evidence). It probably reduces admission to hospital or death within 28 days (RR 0.49, 95% CI 0.31 to 0.75; 36 per 1000; 2 RCTs, 1595 participants; moderate-certainty evidence). Convalescent plasma may have little to no effect on initial symptom resolution at up to day 28 (RR 1.12, 95% CI 0.98 to 1.27; 1 RCT, 416 participants; low-certainty evidence). We did not identify any study reporting other key outcomes. This is a living systematic review. We search monthly for new evidence and update the review when we identify relevant new evidence. AUTHORS' CONCLUSIONS For the comparison of convalescent plasma versus placebo or standard care alone, our certainty in the evidence that convalescent plasma for individuals with moderate to severe disease does not reduce mortality and has little to no impact on clinical improvement or worsening is high. It probably has little to no effect on SAEs. For individuals with mild disease, we have low certainty evidence for our primary outcomes. There are 49 ongoing studies, and 33 studies reported as complete in a trials registry. Publication of ongoing studies might resolve some of the uncertainties around convalescent plasma therapy for people with asymptomatic or mild disease.
PICO Summary
Population
People of any age with mild, moderate or severe COVID-19 (33 randomised controlled trials, n= 24,861).
Intervention
Convalescent plasma (n= 11,432).
Comparison
Standard plasma, human immunoglobulin, placebo or standard care alone.
Outcome
This living systematic review was a fourth review update version and included 33 studies. The authors identified 49 ongoing studies. For the comparison of convalescent plasma versus placebo or standard care alone, the authors’ certainty in the evidence that convalescent plasma for individuals with moderate to severe disease does not reduce mortality and has little to no impact on clinical improvement or worsening is high. For individuals with mild disease, the authors have low certainty evidence for the primary outcomes.
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5.
Pathophysiology and mechanism of long COVID: a comprehensive review
Castanares-Zapatero D, Chalon P, Kohn L, Dauvrin M, Detollenaere J, Maertens de Noordhout C, Primus-de Jong C, Cleemput I, Van den Heede K
Annals of medicine. 2022;54(1):1473-1487
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Editor's Choice
Abstract
BACKGROUND After almost 2 years of fighting against SARS-CoV-2 pandemic, the number of patients enduring persistent symptoms long after acute infection is a matter of concern. This set of symptoms was referred to as "long COVID", and it was defined more recently as "Post COVID-19 condition" by the World health Organization (WHO). Although studies have revealed that long COVID can manifest whatever the severity of inaugural illness, the underlying pathophysiology is still enigmatic. AIM: To conduct a comprehensive review to address the putative pathophysiology underlying the persisting symptoms of long COVID. METHOD We searched 11 bibliographic databases (Cochrane Library, JBI EBP Database, Medline, Embase, PsycInfo, CINHAL, Ovid Nursing Database, Journals@Ovid, SciLit, EuropePMC, and CoronaCentral). We selected studies that put forward hypotheses on the pathophysiology, as well as those that encompassed long COVID patients in their research investigation. RESULTS A total of 98 articles were included in the systematic review, 54 of which exclusively addressed hypotheses on pathophysiology, while 44 involved COVID patients. Studies that included patients displayed heterogeneity with respect to the severity of initial illness, timing of analysis, or presence of a control group. Although long COVID likely results from long-term organ damage due to acute-phase infection, specific mechanisms following the initial illness could contribute to the later symptoms possibly affecting many organs. As such, autonomic nervous system damage could account for many symptoms without clear evidence of organ damage. Immune dysregulation, auto-immunity, endothelial dysfunction, occult viral persistence, as well as coagulation activation are the main underlying pathophysiological mechanisms so far. CONCLUSION Evidence on why persistent symptoms occur is still limited, and available studies are heterogeneous. Apart from long-term organ damage, many hints suggest that specific mechanisms following acute illness could be involved in long COVID symptoms. KEY MESSAGESLong-COVID is a multisystem disease that develops regardless of the initial disease severity. Its clinical spectrum comprises a wide range of symptoms.The mechanisms underlying its pathophysiology are still unclear. Although organ damage from the acute infection phase likely accounts for symptoms, specific long-lasting inflammatory mechanisms have been proposed, as well.Existing studies involving Long-COVID patients are highly heterogeneous, as they include patients with various COVID-19 severity levels and different time frame analysis, as well.
PICO Summary
Population
Patients with long COVID-19 (98 studies).
Intervention
Systematic review to address the putative pathophysiology underlying the persisting symptoms of long COVID-19.
Comparison
Outcome
Of all the included studies, 54 addressed hypotheses concerning potential underlying mechanisms of long COVID-19 symptoms, while 44 studies comprised patient data. Evidence about the persistence of long COVID-19 symptoms was limited, and the underlying mechanisms remained ambiguous. Many hypotheses were put forth by articles reviewing the potential pathophysiology. Included articles reporting patient data were highly heterogeneous, as their patients had various COVID-19 severity levels and different time frame analysis.
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6.
Efficacy of therapeutic plasma exchange in severe COVID-19 disease: A meta-analysis
Prakash S, Sahu A, Routray SS, Maiti R, Mitra JK, Mukherjee S
Vox sanguinis. 2022
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Editor's Choice
Abstract
BACKGROUND AND OBJECTIVES Therapeutic plasma exchange (TPE) has been used in severe COVID-19 disease to eliminate the cytokine storm. This meta-analysis aims to assess the effectiveness of TPE in reducing mortality in severe COVID-19 disease compared to standard treatment. MATERIALS AND METHODS A comprehensive literature search was performed in PubMed, the Cochrane database and the International Clinical Trial Registry Platform (ICTRP). The random-effect model was used to calculate the risk ratio and standardized mean difference (SMD) as pooled effect size for the difference in mortality and length of the intensive care unit (ICU) stay. The risk of bias and publication bias were assessed in R version 4.1.0. The certainty of the evidence was calculated using the GradePro tool. RESULTS The database identified 382 participants from six studies, including one randomized control trial. Egger's test did not detect any publication bias (p = 0.178). The random model analysis for mortality evaluated a risk ratio of 0.38 (95% CI: 0.28-0.52) with a significant reduction in the TPE group. The certainty of the evidence was moderate, with a risk ratio of 0.34 (95% CI: 0.24-0.49). Length of ICU stays between TPE versus standard care showed an SMD of 0.08 (95% CI: -0.38, 0.55) and was not significant. CONCLUSION The length of ICU stay in the TPE group was not different from standard care. However, this meta-analysis revealed a significant benefit of TPE in reducing mortality in severe COVID-19 disease compared to standard treatment.
PICO Summary
Population
Patients with severe COVID-19 disease (6 studies, n= 382).
Intervention
Therapeutic plasma exchange (TPE).
Comparison
Standard treatment.
Outcome
The random model analysis for mortality evaluated a risk ratio of 0.38 (95% CI: 0.28-0.52) with a significant reduction in the TPE group. The certainty of the evidence was moderate, with a risk ratio of 0.34 (95% CI: 0.24-0.49). Length of intensive care unit stays between TPE versus standard care showed a standardized mean difference of 0.08 (95% CI: -0.38-0.55) and was not significant.
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7.
Correlation between ABO blood type, susceptibility to SARS-CoV-2 infection and COVID-19 disease severity: A systematic review
Soares DMB, Araújo Dabs, de Souza JLB, Maurício RB, Soares EMB, Neto FCA, Pinheiro MSN, Gama VCV, Braga-Neto P, Nóbrega PR, et al
Hematology, transfusion and cell therapy. 2022
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Editor's Choice
Abstract
OBJECTIVES To verify the association between the ABO blood type and the risk of SARS-CoV-2 infection and COVID-19 disease severity. METHODS This review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), using the 2020 PRISMA Checklist and flow diagram, and articles selected for review were analyzed using the Newcastle-Ottawa Quality Rating Scale. The research question was: "Would the ABO blood group influence the risk of infection and clinical course of patients infected with SARS-CoV-2?", The following databases were used: Embase, PubMed, Virtual Health Library (VHL), Web of Science, ScienceDirect and Scopus. The protocol for this review was registered in the Prospective Register of Systematic Reviews (PROSPERO), number CRD42021245945. RESULTS We found 798 articles across PubMed, Embase, Scopus, Web of Science, Science Direct and Virtual Health Library and 54 articles were included in the final analysis. Among 30 studies evaluating the risk of COVID-19 infection, 21 found significant correlations with ABO blood groups, 14 of them revealing an increased risk in blood group A and 15 studies showing a decreased risk in blood group O. Most studies found no significant correlation with disease severity or mortality. CONCLUSION The qualitative assessment of available information suggests that blood group A may be a risk factor for COVID-19 infection and that blood group O may have a protective effect. We were unable to determine a clear association between the ABO blood group and mortality. These conclusions are based on highly heterogenous evidence.
PICO Summary
Population
Population at risk for SARS-CoV-2 infection (entire population), (54 studies).
Intervention
ABO blood group.
Comparison
Different blood groups by ABO classification system.
Outcome
Among 30 studies evaluating the risk of COVID-19 infection, 21 found significant correlations with ABO blood groups, 14 of them revealing an increased risk in blood group A and 15 studies showing a decreased risk in blood group O. Most studies found no significant correlation with disease severity or mortality.
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Effective antiviral regimens to reduce COVID-19 hospitalizations: a systematic comparison of randomized controlled trials
Sullivan DJ, Focosi D, Hanley D, Franchini M, Ou J, Casadevall A, Paneth N
medRxiv : the preprint server for health sciences. 2022
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Editor's Choice
Abstract
BACKGROUND Antiviral therapy has a greater impact when provided early in the disease to outpatients, potentially preventing hospitalization and subsequent deaths, while reducing healthcare system pressure. Controversies persist about the best treatment option for COVID-19 outpatients at risk of disease progression to hospital. No head-to-head RCT has been conducted to compare the three major modalities in current use-oral/intravenous antivirals, monoclonal antibodies and COVID-19 convalescent plasma (CCP). METHODS We assembled data from March 2020 to April 2022 from published outpatient RCTs examining authorized COVID-19 therapies with hospitalization as the major endpoint, and that also assessed mortality, symptom resolution, underlying risk factors for progression, timing and dose of the intervention in relationship to evolving variants of concern (VOC). FINDINGS CCP, monoclonal antibodies and oral antivirals each had comparable efficacy converging to 80% hospital risk reduction dependent on the dose and the timing of the intervention. Most RCTs targeted populations with at least one risk factor for severe COVID-19. Control group hospitalizations were less than 10% in 16 of 20 RCTs. Amongst the effective two CCP trials, monoclonals and three antiviral small molecules, deaths were reduced by 90% from 44 total in combined control arm to 4 in intervention arms. The overall risk of bias was deemed low for nine studies and some concerns for eight. The I (2) statistic heterogeneity amongst the outpatient trials with endpoint hospitalization is 72% (p-< 0.01). INTERPRETATION The emerging resistance of Omicron BA.2 and related sublineages (XE, BA.2.12.1, BA.4, and BA.5) to monoclonal antibodies suggests a pressing need to reevaluate CCP (nowadays largely available from vaccinees with high neutralizing antibody levels) for COVID19 outpatients at risk of disease progression, especially in settings with constrained medical resources. FUNDING This study was funded by the US Department of Defense, in collaboration with the Defense Health Agency and NIH. RESEARCH IN CONTEXT Evidence before this study: To date no head-to-head randomized controlled trial (RCT) has ever compared treatment options for COVID-19 outpatients, making comparisons and treatment choices difficult. We assembled RCTs with hospitalization as the primary endpoint. A literature search of MEDLINE (through PubMed), medRxiv and bioRxiv databases was carried out inclusive of RCTs published from March 2020 to April 2022 inclusive, using the search terms ("COVID-19" OR "SARS-CoV-2" OR "coronavirus disease 2019") AND ("treatment" OR "therapy") AND ("outpatient" OR "hospitalization"). The risk of bias obtained at COVID-19-Network Meta-Analysis (NMA), was low in half of the studies with some concerns for the remaining.Added value of this study: This systematic review compared outcomes among RCTs of outpatient therapy for COVID-19, taking into account time between onset of symptoms and treatment administration. We found that small-chemical antivirals, convalescent plasma and anti-Spike monoclonal antibodies had comparable efficacy. Trials of monoclonals were performed prior to the recognition that they had become ineffective against the Omicron sublineages.Implications of all the available evidence: Monoclonal antibodies and small chemical antivirals each have drawbacks. Both take time to be developed and are expensive. Monoclonals can lose efficacy with viral mutation, and chemical antivirals have contraindications and adverse events. Convalescent plasma retains its potency and is likely to be the only accessible therapeutic option for low-and-middle income countries.
PICO Summary
Population
COVID-19 outpatients at risk of disease progression (20 studies).
Intervention
Convalescent plasma (CCP).
Comparison
Antiviral agents; monoclonal antibodies.
Outcome
CCP, monoclonal antibodies and oral antivirals each had comparable efficacy converging to 80% hospital risk reduction dependent on the dose and the timing of the intervention. Most randomised controlled trials (RCTs) targeted populations with at least one risk factor for severe COVID-19. Control group hospitalizations were less than 10% in 16 of 20 RCTs. Amongst the effective two CCP trials, monoclonals and three antiviral small molecules, deaths were reduced by 90% from 44 total in combined control arm to 4 in intervention arms. The overall risk of bias was deemed low for nine studies.
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The effect of intravenous immunoglobulins on the outcomes of patients with COVID-19: a systematic review and meta-analysis of randomized controlled trials
Lai CC, Chen WC, Chen CY, Wei YF
Expert review of anti-infective therapy. 2022;:1-8
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Editor's Choice
Abstract
OBJECTIVES Severe-to-critical COVID-19 has been associated with exaggerated immune responses, and anti-inflammatory agents including corticosteroid and interleukin-6 antagonist have been repurposed as the treatment modality against severe SARS-CoV-2 infections. However, the clinical efficacy and safety of intravenous immunoglobulin (IVIG) in the treatment of patients with COVID-19 was controversial. METHODS This meta-analysis of randomized controlled trials (RCTs) investigated the effectiveness of IVIG in patients with COVID-19. Electronic databases were searched for RCTs that compared the clinical efficacy of IVIG with standard of care or placebo in the hospitalized patients with COVID-19 were included. RESULTS Six RCTs involving 472 patients were included. Patients who received IVIG had a similar mortality rate to the controls (25.3% vs 27.0%, odds ratio [OR], 0.60; 95% confidence interval [CI], 0.27-1.31). Compared with the control group, the study group demonstrated a similar incidence of receiving mechanical ventilation (OR, 0.70; 95% CI, 0.45-1.11), intensive care unit (ICU) admission (OR, 0.58; 95% CI, 0.22-1.53), length of hospital stay (mean difference [MD], -1.81 days; 95% CI, -8.42 to 4.81) and ICU stay (MD, -0.61 days; 95% CI, -2.80 to 1.58). CONCLUSIONS The administration of IVIG in hospitalized patients with COVID-19 does not improve clinical outcomes.
PICO Summary
Population
Hospitalised patients with COVID-19 (6 studies, n= 472).
Intervention
Intravenous immunoglobulin IVIG (Study group).
Comparison
Standard care or placebo (Control group).
Outcome
Patients who received IVIG had a similar mortality rate compared to patients receiving standard care or placebo (25.3% vs. 27.0%). Compared with the Control group, the Study group demonstrated a similar incidence of receiving mechanical ventilation, intensive care unit (ICU) admission, length of hospital stay (mean difference (MD) -1.81 days) and ICU stay (MD -0.61 days).
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A systematic review of the safety and efficacy of convalescent plasma or immunoglobulin treatment for people with severe respiratory viral infections due to coronaviruses or influenza
Kimber C, Lamikanra AA, Geneen LJ, Sandercock J, Dorée C, Valk SJ, Estcourt LJ
Transfusion medicine (Oxford, England). 2022
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Editor's Choice
Abstract
OBJECTIVE Evaluate the safety and effectiveness of convalescent plasma (CP) or hyperimmune immunoglobulin (hIVIG) in severe respiratory disease caused by coronaviruses or influenza, in patients of all ages requiring hospital admission. METHODS We searched multiple electronic databases for all publications to 12th October 2020, and RCTs only to 28th June 2021. Two reviewers screened, extracted, and analysed data. We used Cochrane ROB (Risk of Bias)1 for RCTs, ROBINS-I for non-RCTs, and GRADE to assess the certainty of the evidence. RESULTS Data from 30 RCTs and 2 non-RCTs showed no overall difference between groups for all-cause mortality and adverse events in four comparisons. Certainty of the evidence was downgraded for high ROB and imprecision. (1) CP versus standard care (SoC) (20 RCTS, 2 non-RCTs, very-low to moderate-high certainty); (2) CP versus biologically active control (6 RCTs, very-low certainty); (3) hIVIG versus SoC (3 RCTs, very-low certainty); (4) early CP versus deferred CP (1 RCT, very-low certainty). Subgrouping by titre improved precision in one outcome (30-day mortality) for the 'COVID high-titre' category in Comparison 1 (no difference, high certainty) and Comparison 2 (favours CP, very-low certainty). Post hoc analysis suggests a possible benefit of CP in patients testing negative for antibodies at baseline, compared with those testing positive. CONCLUSION A minimum titre should be established and ensured for a positive biological response to the therapy. Further research on the impact of CP/hIVIG in patients who have not yet produced antibodies to the virus would be useful to target therapies at groups who will potentially benefit the most.
PICO Summary
Population
Patients of all ages with severe respiratory viral infections due to coronaviruses or influenza (32 studies).
Intervention
Convalescent plasma (CP). Early CP. Hyperimmune immunoglobulin (hIVIG).
Comparison
Various comparators including: standard care (SoC), biologically active control, and deferred CP.
Outcome
Data from 30 randomised controlled trials (RCTs) and 2 non-RCTs showed no overall difference between groups for all-cause mortality and adverse events in four comparisons. Certainty of the evidence was downgraded for high risk of bias and imprecision. 1) CP vs. SoC, (20 RCTS, 2 non-RCTs, very-low to moderate-high certainty). 2) CP vs. biologically active control (6 RCTs, very-low certainty). 3) hIVIG vs. SoC (3 RCTs, very-low certainty). 4) Early CP vs. deferred CP (1 RCT, very-low certainty). Subgrouping by titre improved precision in one outcome (30-day mortality) for the 'COVID high-titre' category in Comparison 1 (no difference, high certainty) and Comparison 2 (favoured CP, very-low certainty). Post hoc analysis suggested a possible benefit of CP in patients testing negative for antibodies at baseline, compared with those testing positive.