Convalescent Plasma Therapy in Coronavirus Disease 2019: a Case Report and Suggestions to Overcome Obstacles

A Narrative Overview of Coronavirus Infection: Clinical Signs and Symptoms, Viral Entry and Replication, Treatment Modalities, and Management

The global pandemic known as coronavirus disease (COVID-19) is causing morbidity and mortality on a daily basis. The severe acute respiratory syndrome coronavirus-2 (SARS-CoV- -2) virus has been around since December 2019 and has infected a high number of patients due to its idiopathic pathophysiology and rapid transmission. COVID-19 is now deemed a newly identified "syndrome" condition since it causes a variety of unpleasant symptoms and systemic side effects following the pandemic. Simultaneously, it always becomes potentially hazardous when new variants develop during evolution. Its random viral etiology prevents accurate and suitable therapy. Despite the fact that multiple preclinical and research studies have been conducted to combat this lethal virus, and various therapeutic targets have been identified, the precise course of therapy remains uncertain. However, just a few drugs have shown efficacy in treating this viral infection in its early stages. Currently, several medicines and vaccinations have been licensed following clinical trial research, and many countries are competing to find the most potent and effective immunizations against this highly transmissible illness. For this narrative review, we used PubMed, Google Scholar, and Scopus to obtain epidemiological data, pre-clinical and clinical trial outcomes, and recent therapeutic alternatives for treating COVID-19 viral infection. In this study, we discussed the disease's origin, etiology, transmission, current advances in clinical diagnostic technologies, different new therapeutic targets, pathophysiology, and future therapy options for this devastating virus. Finally, this review delves further into the hype surrounding the SARS-CoV-2 illness, as well as present and potential COVID-19 therapies.

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

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.

Potential treatments of COVID-19: Drug repurposing and therapeutic interventions

The coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The infection is caused when Spike-protein (S-protein) present on the surface of SARS-CoV-2 interacts with human cell surface receptor, Angiotensin-converting enzyme 2 (ACE2). This binding facilitates SARS-CoV-2 genome entry into the human cells, which in turn causes infection. Since the beginning of the pandemic, many different therapies have been developed to combat COVID-19, including treatment and prevention. This review is focused on the currently adapted and certain other potential therapies for COVID-19 treatment, which include drug repurposing, vaccines and drug-free therapies. The efficacy of various treatment options is constantly being tested through clinical trials and in vivo studies before they are made medically available to the public.

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

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.

How We Have Treated Severe to Critically Ill Patients With Coronavirus Disease 2019 in Korea

Since 2019, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread worldwide, and the coronavirus disease 2019 (COVID-19) pandemic currently continues. In response to this unprecedented pandemic, several researchers and medical staff have struggled to find appropriate treatments for COVID-19. Patients with mild symptoms can recuperate with symptomatic care, however establishing treatment for severe to critically ill patients who can have a high mortality has been essential. Accordingly, the guidelines for COVID-19 treatment have evolved through numerous trials and errors and have been relatively well established to date. In the Republic of Korea, several evidence-based guidelines for COVID-19 treatment were released and revised, reflecting various research and regional medical conditions. To date, approximately 3 years after the beginning of the COVID-19 pandemic, we are reflecting on the changes in the guidelines thus far and have summarized the treatment experience of severe to critically ill patients with COVID-19. The Korean guidelines for COVID-19 treatment have been updated continuously as the National Institutes of Health (NIH) guidelines have changed. Dexamethasone is currently used as the backbone for the treatment of severe to critically ill patients with COVID-19, and remdesivir, baricitinib, and tocilizumab can be added depending on a patient's situation. In addition, venous thromboembolism prophylaxis is one of the important adjunctive therapies for patients with severe COVID-19. In the clinical field, treatment of severely ill patients with COVID-19 based on guidelines is widely practiced by medical staff and established currently.

Perplexing issues for convalescent immune plasma therapy in COVID-19

Convalescent immune plasma (CIP) therapy in coronavirus disease 2019 (COVID-19) is presently a trendy choice of treatment. On March 24, 2020, the United States Food and Drug Administration approved of CIP treatment for seriously ill COVID-19 patients as an emergency investigational new drug. The precise mechanisms of action for CIP in COVID-19 have not yet been undoubtedly recognized. However, earlier research demonstrated that the main mechanism of CIP such as in other viral infections is viral neutralization. Systematic reviews and meta-analyses of the CIP transfusion in severe infectious diseases have shown that CIP has some beneficial effects and it is a harmless process to cure infectious diseases early after symptom beginning. It is suggested that SARS-CoV-2 neutralizing antibody titers in CIP should be ideally higher than 1:320, but lower thresholds could also be useful. The suggested minimum dose for one individual is one unit (200 mL) of CIP. The second unit can be given 48 h succeeding the end of the transfusion of the first unit of CIP. Moreover, CIP can be applied up to a maximum of three units (600 mL). CIP could be administered in other systemic diseases, viral infections coincidentally associated with SARS-CoV-2 infection, as well as other therapeutic approaches for COVID-19. There are generally no serious adverse events described from CIP transfusion in these recipients. CIP may have a significant role as one of the therapeutic modalities for various viral infections when enough vaccines or other specific therapeutic agents are not on hand.

A Transient Effect of Convalescent Plasma Therapy in a Patient with Severe Covonavirus Disease 2019: A Case Report

A 65-year-old male patient with an end-stage renal disease was diagnosed with coronavirus disease 2019 (COVID-19) by reverse transcription polymerase chain reaction. The patient complained of cough, sputum, and respiratory distress that worsened three days ago. The patient required mechanical ventilation and extracorporeal mentrane oxygenation. On day 9, convalescent plasma collected from a 34-year old man who recovered from COVID-19 45 days ago was administered. The patient showed immediate clinical improvement. However, on day 14, the patient’s clinical course worsened again. On day 19 and day 24, vancomycin-resistant Enterococcus faecium bacteremia and methicillin-resistant Staphylococcus aureus pneumonia were found. After long-term supportive care, he slowly recovered. He was discharged on day 91 without any oxygen requirement. This case report suggests that convalescent plasma therapy might just provide a short-term relief and that persistent effort for critical care is necessary to save patients from severe COVID-19.

Convalescent plasma bank facility location-allocation problem for COVID-19

With convalescent plasma being recognized as an eminent treatment option for COVID-19, this paper addresses the location-allocation problem for convalescent plasma bank facilities. This is a critical topic, since limited supply and overtly increasing cases demand a well-established supply chain. We present a novel plasma supply chain model considering stochastic parameters affecting plasma demand and the unique features of the plasma supply chain. The primary objective is to first determine the optimal location of the plasma banks and to then allocate the plasma collection facilities so as to maintain proper plasma flow within the network. In addition, recognizing the perishable nature of plasma, we integrate a deteriorating rate with the objective that as little plasma as possible is lost. We formulate a robust mixed-integer linear programming (MILP) model by considering two conflicting objective functions, namely the minimization of overall plasma transportation time and total plasma supply chain network cost, with the latter also capturing inventory costs to reduce wastage. We then propose a CPLEX-based optimization approach for solving the MILP functions. The feasibility of our results is validated by a comparison study using the Non-Dominated Sorting Genetic Algorithm-II (NSGA-II) and a proposed modified NSGA-III. The application of the proposed model is evaluated by implementing it in a real-world case study within the context of India. The optimized numerical results, together with their sensitivity analysis, provide valuable decision support for policymakers.

Compassionate Use of GC5131 (Hyperimmunoglobulin) Therapy in Critically Ill Patients Diagnosed with COVID-19: A Case Series and Review of Literature

Presently, the use of convalescent plasma and hyperimmunoglobulin obtained from individuals who have recovered from coronavirus disease 2019 (COVID-19) has proved to potentially provide passive antibody-based immunity, thereby leading to several clinical trials to develop an immune-based COVID-19 treatment. However, the therapeutic efficacy of hyperimmunoglobulin in critically ill patients with COVID-19 remains unknown. On 23 October 2020, we first administered GC5131 in a compassionate-use program to critically ill patients at the Kyungpook National University, Chilgok Hospital, Korea. Since then, five more critically ill patients were treated with GC5131 in this compassionate-use program in our hospital up until 17 December 2020. We retrospectively reviewed the clinical responses of six critically ill patients diagnosed with COVID-19 who received the hyperimmunoglobulin concentrate, GC5131, which was produced by the Green Cross Corporation. After the administration of GC5131, five patients died due to an exacerbation of COVID-19 pneumonia. GC5131 was ineffective when administered to critically ill patients with COVID-19. Nevertheless, we propose that to expect a therapeutic effect from GC5131, it should be administered as early as possible to avoid the excessive inflammatory response phase in patients with severe and advanced COVID-19 infection. This step was difficult to achieve in the real world due to the time required for decision making and the process of the compassionate-use program.

Clinical Management of COVID-19: A Review of Pharmacological Treatment Options

Since the outbreak and subsequent declaration of COVID-19 as a global pandemic in March 2020, concerted efforts have been applied by the scientific community to curtail the spread of the disease and find a cure. While vaccines constitute a vital part of the public health strategy to reduce the burden of COVID-19, the management of this disease will continue to rely heavily on pharmacotherapy. This study aims to provide an updated review of pharmacological agents that have been developed and/or repurposed for the treatment of COVID-19. To this end, a comprehensive literature search was conducted using the PubMed, Google Scholar, and LitCovid databases. Relevant clinical studies on drugs used in the management of COVID-19 were identified and evaluated in terms of evidence of efficacy and safety. To date, the FDA has approved three therapies for the treatment of COVID-19 Emergency Use Authorization: convalescent plasma, remdesivir, and casirivimab/imdevimab (REGN-COV2). Drugs such as lopinavir/ritonavir, umifenovir, favipiravir, anakinra, chloroquine, hydroxychloroquine, tocilizumab, interferons, tissue plasminogen activator, intravenous immunoglobulins, and nafamosat have been used off-label with mixed therapeutic results. Adjunctive administration of corticosteroids is also very common. The clinical experience with these approved and repurposed drugs is limited, and data on efficacy for the new indication are not strong. Overall, the response of the global scientific community to the COVID-19 pandemic has been impressive, as evident from the volume of scientific literature elucidating the molecular biology and pathophysiology of SARS-CoV-2 and the approval of three new drugs for clinical management. Reviewed studies have shown mixed data on efficacy and safety of the currently utilized drugs. The lack of standard treatment for COVID-19 has made it difficult to interpret results from most of the published studies due to the risk of attribution error. The long-term effects of drugs can only be assessed after several years of clinical experience; therefore, the efficacy and safety of current COVID-19 therapeutics should continue to be rigorously monitored as part of post-marketing studies.

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.

Convalescent Plasma Transfusion for the Treatment of COVID-19 in Adults: A Global Perspective

More than one year into the novel coronavirus disease 2019 (COVID-19) pandemic, healthcare systems across the world continue to be overwhelmed with soaring daily cases. The treatment spectrum primarily includes ventilation support augmented with repurposed drugs and/or convalescent plasma transfusion (CPT) from recovered COVID-19 patients. Despite vaccine variants being recently developed and administered in several countries, challenges in global supply chain logistics limit their timely availability to the wider world population, particularly in developing countries. Given the measured success of conventional CPT in treating several infections over the past decade, recent studies have reported its effectiveness in decreasing the duration and severity of COVID-19 symptoms. In this review, we conduct a literature search of published studies investigating the use of CPT to treat COVID-19 patients from January 2020 to January 2021. The literature search identified 181 records of which 39 were included in this review. A random-effects model was used to aggregate data across studies, and mortality rates of 17 vs. 32% were estimated for the CPT and control patient groups, respectively, with an odds ratio (OR) of 0.49. The findings indicate that CPT shows potential in reducing the severity and duration of COVID-19 symptoms. However, early intervention (preferably within 3 days), recruitment of donors, and plasma potency introduce major challenges for its scaled-up implementation. Given the low number of existing randomized clinical trials (RCTs, four with a total of 319 patients), unanticipated risks to CPT recipients are highlighted and discussed. Nevertheless, CPT remains a promising COVID-19 therapeutic option that merits internationally coordinated RCTs to achieve a scientific risk-benefit consensus.

The Effect of Convalescent Plasma Therapy on Mortality Among Patients With COVID-19: Systematic Review and Meta-analysis

To determine the effect of COVID-19 convalescent plasma on mortality, we aggregated patient outcome data from 10 randomized clinical trials, 20 matched control studies, 2 dose-response studies, and 96 case reports or case series. Studies published between January 1, 2020, and January 16, 2021, were identified through a systematic search of online PubMed and MEDLINE databases. Random effects analyses of randomized clinical trials and matched control data demonstrated that patients with COVID-19 transfused with convalescent plasma exhibited a lower mortality rate compared with patients receiving standard treatments. Additional analyses showed that early transfusion (within 3 days of hospital admission) of higher titer plasma is associated with lower patient mortality. These data provide evidence favoring the efficacy of human convalescent plasma as a therapeutic agent in hospitalized patients with COVID-19.

Antibody Responses in COVID-19: A Review

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to spread worldwide as a severe pandemic. Although its seroprevalence is highly variable among territories, it has been reported at around 10%, but higher in health workers. Evidence regarding cross-neutralizing response between SARS-CoV and SARS-CoV-2 is still controversial. However, other previous coronaviruses may interfere with SARS-CoV-2 infection, since they are phylogenetically related and share the same target receptor. Further, the seroconversion of IgM and IgG occurs at around 12 days post onset of symptoms and most patients have neutralizing titers on days 14-20, with great titer variability. Neutralizing antibodies correlate positively with age, male sex, and severity of the disease. Moreover, the use of convalescent plasma has shown controversial results in terms of safety and efficacy, and due to the variable immune response among individuals, measuring antibody titers before transfusion is mostly required. Similarly, cellular immunity seems to be crucial in the resolution of the infection, as SARS-CoV-2-specific CD4+ and CD8+ T cells circulate to some extent in recovered patients. Of note, the duration of the antibody response has not been well established yet.

Convalescent Plasma for the Prevention and Treatment of COVID-19: A Systematic Review and Quantitative Analysis

BACKGROUND

The COVID-19 pandemic, caused by a novel coronavirus termed SARS-CoV-2, has spread quickly worldwide. Convalescent plasma (CP) obtained from patients following recovery from COVID-19 infection and development of antibodies against the virus is an attractive option for either prophylactic or therapeutic treatment, since antibodies may have direct or indirect antiviral activities and immunotherapy has proven effective in principle and in many clinical reports.

OBJECTIVE

We seek to characterize the latest advances and evidence in the use of CP for COVID-19 through a systematic review and quantitative analysis, identify knowledge gaps in this setting, and offer recommendations and directives for future research.

METHODS

PubMed, Web of Science, and Embase were continuously searched for studies assessing the use of CP for COVID-19, including clinical studies, commentaries, reviews, guidelines or protocols, and in vitro testing of CP antibodies. The screening process and data extraction were performed according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Quality appraisal of all clinical studies was conducted using a universal tool independent of study designs. A meta-analysis of case-control and randomized controlled trials (RCTs) was conducted using a random-effects model.

RESULTS

Substantial literature has been published covering various aspects of CP therapy for COVID-19. Of the references included in this review, a total of 243 eligible studies including 64 clinical studies, 79 commentary articles, 46 reviews, 19 guidance and protocols, and 35 in vitro testing of CP antibodies matched the criteria. Positive results have been mostly observed so far when using CP for the treatment of COVID-19. There were remarkable heterogeneities in the CP therapy with respect to patient demographics, donor antibody titers, and time and dose of CP administration. The studies assessing the safety of CP treatment reported low incidence of adverse events. Most clinical studies, in particular case reports and case series, had poor quality. Only 1 RCT was of high quality. Randomized and nonrandomized data were found in 2 and 11 studies, respectively, and were included for meta-analysis, suggesting that CP could reduce mortality and increase viral clearance. Despite promising pilot studies, the benefits of CP treatment can only be clearly established through carefully designed RCTs.

CONCLUSIONS

There is developing support for CP therapy, particularly for patients who are critically ill or mechanically ventilated and resistant to antivirals and supportive care. These studies provide important lessons that should inform the planning of well-designed RCTs to generate more robust knowledge for the efficacy of CP in patients with COVID-19. Future research is necessary to fill the knowledge gap regarding prevention and treatment for patients with COVID-19 with CP while other therapeutics are being developed.

Clinical and Virologic Effectiveness of Remdesivir Treatment for Severe Coronavirus Disease 2019 (COVID-19) in Korea: a Nationwide Multicenter Retrospective Cohort Study

BACKGROUND

Remdesivir is widely used for the treatment of coronavirus disease 2019 (COVID-19), but controversies regarding its efficacy still remain.

METHODS

A retrospective cohort study was conducted to evaluate the effect of remdesivir on clinical and virologic outcomes of severe COVID-19 patients from June to July 2020. Primary clinical endpoints included clinical recovery, additional mechanical ventilator (MV) support, and duration of oxygen or MV support. Viral load reduction by hospital day (HD) 15 was evaluated by calculating changes in cycle threshold (Ct) values.

RESULTS

A total of 86 severe COVID-19 patients were evaluated including 48 remdesivir-treated patients. Baseline characteristics were not significantly different between the two groups. Remdesivir was administered an average of 7.42 days from symptom onset. The proportions of clinical recovery of the remdesivir and supportive care group at HD 14 (56.3% and 39.5%) and HD 28 (87.5% and 78.9%) were not statistically different. The proportion of patients requiring MV support by HD 28 was significantly lower in the remdesivir group than in the supportive care group (22.9% vs. 44.7%, P = 0.032), and MV duration was significantly shorter in the remdesivir group (average, 1.97 vs. 5.37 days; P = 0.017). Analysis of upper respiratory tract specimens demonstrated that increases of Ct value from HD 1-5 to 11-15 were significantly greater in the remdesivir group than the supportive care group (average, 10.19 vs. 5.36; P = 0.007), and the slope of the Ct value increase was also significantly steeper in the remdesivir group (average, 5.10 vs. 2.68; P = 0.007).

CONCLUSION

The remdesivir group showed clinical and virologic benefit in terms of MV requirement and viral load reduction, supporting remdesivir treatment for severe COVID-19.

The Effect of Convalescent Plasma Therapy on COVID-19 Patient Mortality: Systematic Review and Meta-analysis

To determine the effect of COVID-19 convalescent plasma on mortality, we aggregated patient outcome data from 10 randomized clinical trials (RCT), 20 matched-control studies, two dose-response studies, and 96 case-reports or case series. Studies published between January 1, 2020 to January 16, 2021 were identified through a systematic search of online PubMed and MEDLINE databases. Random effects analyses of RCT and matched-control data demonstrated that COVID-19 patients transfused with convalescent plasma exhibited a lower mortality rate compared to patients receiving standard treatments. Additional analyses showed that early transfusion (within 3 days of hospital admission) of higher titer plasma is associated with lower patient mortality. These data provide evidence favoring the efficacy of human convalescent plasma as a therapeutic agent in hospitalized COVID-19 patients.

Convalescent plasma may be a possible treatment for COVID-19: A systematic review

INTRODUCTION

The coronavirus disease 2019 (COVID-19) pandemic has spread globally. Therapeutic options including antivirals, anti-inflammatory compounds, and vaccines are still under study. Convalescent plasma(CP) immunotherapy was an effective method for fighting against similar viral infections such as SARS-CoV, and MERS-CoV. In the epidemic of COVID-19, a large number of literatures reported the application of CP. However, there is controversy over the efficacy of CP therapy for COVID-19. This systematic review was designed to evaluate the existing evidence and experience related to CP immunotherapy for COVID-19.

METHODS

A literature search was conducted on Pubmed, Cochrane Library, Clinical Key, Wanfang Database; China National Knowledge Infrastructure(CNKI) were used to search for the proper keywords such as SARS-CoV-2, COVID-19, plasma, serum, immunoglobulins, blood transfusion, convalescent, novel coronavirus, immune and the related words for publications published until 15.10.2020. Other available resources were also used to identify relevant articles. The present systematic review was performed based on PRISMA protocol. Data extraction and risk of bias assessments were performed by two reviewers.

RESULTS

Based on the inclusions and exclusions criteria, 45 articles were included in the final review. First, meta-analysis results of RCTs showed that, there were no statistically significant differences between CP transfusion and the control group in terms of reducing mortality(OR 0.79, 95% CI 0.52-1.19, I2 = 28%) and improving clinical symptoms(OR 1.21, 95%CI 0.68-2.16; I2 = 0%). The results of controlled NRSIs showed that CP therapy may reduce mortality in COVID-19 patients(RR 0.59, 95% CI 0.53-0.66, I2 = 0%). Second, limited safety data suggested that CP is a well-tolerated therapy with a low incidence of adverse events. But, due to lack of safety data for the control group, it is really not easy to determine whether CP transfusion has an impact on moderate to serious AEs. Thirdly, for children, pregnant, elderly, tumor and immunocompromised patients, CP may be a well-tolerated therapy, if the disease cannot be controlled and continues to progress. Studies were commonly of low or very low quality.

CONCLUSIONS

Although the results of limited RCTs showed that CP cannot significantly reduce mortality, some non-RCTs and case report(series) have found that CP may help patients improve clinical symptoms, clear the virus, and reduce mortality, especially for patients with COVID-19 within ten days of illness. We speculate that CP may be a possible treatment option. High-quality studies are needed for establishing stronger quality of evidence and pharmacists should also be actively involved in the CP treatment process and provide close pharmaceutical care.

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 currently being investigated in trials as potential therapy for coronavirus disease 2019 (COVID-19). A thorough understanding of the current body of evidence regarding the benefits and risks is required.  OBJECTIVES: To continually assess, as more evidence becomes available, whether convalescent plasma or hyperimmune immunoglobulin transfusion is effective and safe in treatment of people with COVID-19.

SEARCH METHODS

We searched the World Health Organization (WHO) COVID-19 Global Research Database, MEDLINE, Embase, Cochrane COVID-19 Study Register, Centers for Disease Control and Prevention COVID-19 Research Article Database and trial registries to identify completed and ongoing studies on 19 August 2020.

SELECTION CRITERIA

We followed standard Cochrane methodology. We included studies evaluating convalescent plasma or hyperimmune immunoglobulin for people with COVID-19, irrespective of study design, disease severity, age, gender or ethnicity. We excluded studies including populations with other coronavirus diseases (severe acute respiratory syndrome (SARS) or Middle East respiratory syndrome (MERS)) and 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' 2.0 tool for randomised controlled trials (RCTs), the Risk of Bias in Non-randomised Studies - of Interventions (ROBINS-I) tool for controlled non-randomised studies of interventions (NRSIs), and the assessment criteria for observational studies, provided by Cochrane Childhood Cancer for non-controlled NRSIs. We rated the certainty of evidence using the GRADE approach for the following outcomes: all-cause mortality at hospital discharge, mortality (time to event), improvement of clinical symptoms (7, 15, and 30 days after transfusion), grade 3 and 4 adverse events (AEs), and serious adverse events (SAEs).

MAIN RESULTS

This is the second living update of our review. We included 19 studies (2 RCTs, 8 controlled NRSIs, 9 non-controlled NRSIs) with 38,160 participants, of whom 36,081 received convalescent plasma. Two completed RCTs are awaiting assessment (published after 19 August 2020). We identified a further 138 ongoing studies evaluating convalescent plasma or hyperimmune immunoglobulin, of which 73 are randomised (3 reported in a study registry as already being completed, but without results). We did not identify any completed studies evaluating hyperimmune immunoglobulin. We did not include data from controlled NRSIs in data synthesis because of critical risk of bias. The overall certainty of evidence was low to very low, due to study limitations and results including both potential benefits and harms.  Effectiveness of convalescent plasma for people with COVID-19  We included results from two RCTs (both stopped early) with 189 participants, of whom 95 received convalescent plasma. Control groups received standard care at time of treatment without convalescent plasma. We are uncertain whether convalescent plasma decreases all-cause mortality at hospital discharge (risk ratio (RR) 0.55, 95% confidence interval (CI) 0.22 to 1.34; 1 RCT, 86 participants; low-certainty evidence).  We are uncertain whether convalescent plasma decreases mortality (time to event) (hazard ratio (HR) 0.64, 95% CI 0.33 to 1.25; 2 RCTs, 189 participants; low-certainty evidence). Convalescent plasma may result in little to no difference in improvement of clinical symptoms (i.e. need for respiratory support) at seven days (RR 0.98, 95% CI 0.30 to 3.19; 1 RCT, 103 participants; low-certainty evidence). Convalescent plasma may increase improvement of clinical symptoms at up to 15 days (RR 1.34, 95% CI 0.85 to 2.11; 2 RCTs, 189 participants; low-certainty evidence), and at up to 30 days (RR 1.13, 95% CI 0.88 to 1.43; 2 studies, 188 participants; low-certainty evidence).  No studies reported on quality of life.  Safety of convalescent plasma for people with COVID-19 We included results from two RCTs, eight controlled NRSIs and nine non-controlled NRSIs assessing safety of convalescent plasma. Reporting of safety data and duration of follow-up was variable. The controlled studies reported on AEs and SAEs only in participants receiving convalescent plasma. Some, but not all, studies included death as a SAE.  The studies did not report the grade of AEs. Fourteen studies (566 participants) reported on AEs of possible grade 3 or 4 severity. The majority of these AEs were allergic or respiratory events. We are very uncertain whether convalescent plasma therapy affects the risk of moderate to severe AEs (very low-certainty evidence).  17 studies (35,944 participants) assessed SAEs for 20,622 of its participants. The majority of participants were from one non-controlled NRSI (20,000 participants), which reported on SAEs within the first four hours and within an additional seven days after transfusion. There were 63 deaths, 12 were possibly and one was probably related to transfusion. There were 146 SAEs within four hours and 1136 SAEs within seven days post-transfusion. These were predominantly allergic or respiratory, thrombotic or thromboembolic and cardiac events. We are uncertain whether convalescent plasma therapy results in a clinically relevant increased risk of SAEs (low-certainty evidence).

AUTHORS' CONCLUSIONS

We are uncertain whether convalescent plasma is beneficial for people admitted to hospital with COVID-19. There was limited information regarding grade 3 and 4 AEs to determine the effect of convalescent plasma therapy on clinically relevant SAEs. In the absence of a control group, we are unable to assess the relative safety of convalescent plasma therapy.  While major efforts to conduct research on COVID-19 are being made, recruiting the anticipated number of participants into these studies is problematic. The early termination of the first two RCTs investigating convalescent plasma, and the lack of data from 20 studies that have completed or were due to complete at the time of this update illustrate these challenges. Well-designed studies should be prioritised. Moreover, studies should report outcomes in the same way, and should consider the importance of maintaining comparability in terms of co-interventions administered in all study arms.  There are 138 ongoing studies evaluating convalescent plasma and hyperimmune immunoglobulin, of which 73 are RCTs (three already completed). This is the second living update of the review, and we will continue to update this review periodically. Future updates may show different results to those reported here.

Treatment of COVID-19 with convalescent plasma: lessons from past coronavirus outbreaks

BACKGROUND

There is currently no treatment known to alter the course of coronavirus disease 2019 (COVID-19). Convalescent plasma has been used to treat a number of infections during pandemics, including severe acute respiratory syndrome coronavirus (SARS-CoV), Middle Eastern respiratory syndrome coronavirus (MERS-CoV) and now severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2).

OBJECTIVES

To summarize the existing literature and registered clinical trials on the efficacy and safety of convalescent plasma for treating coronaviruses, and discuss issues of feasibility, and donor and patient selection.

SOURCES

A review of articles published in PubMed was performed on 13 July 2020 to summarize the currently available evidence in human studies for convalescent plasma as a treatment for coronaviruses. The World Health Organization International Clinical Trials Registry and clinicaltrials.gov were searched to summarize the currently registered randomized clinical trials for convalescent plasma in COVID-19.

CONTENT

There were sixteen COVID-19, four MERS and five SARS reports describing convalescent plasma use in humans. There were two randomized control trials, both of which were for COVID-19 and were terminated early. Most COVID-19 reports described a potential benefit of convalescent plasma on clinical outcomes in severe or critically ill patients with few immediate adverse events. However, there were a number of limitations, including the concurrent use of antivirals, steroids and other treatments, small sample sizes, lack of randomization or control groups, and short follow-up time. Data from SARS and COVID-19 suggest that earlier administration probably yields better outcomes. The ideal candidates for recipients and donors are not known. Still, experience with previous coronaviruses tells us that antibodies in convalescent patients are probably short-lived. Patients who had more severe disease and who are earlier in their course of recovery may be more likely to have adequate titres. Finally, a number of practical challenges were identified.

IMPLICATIONS

There is currently no effective treatment for COVID-19, and preliminary trials for convalescent plasma suggest that there may be some benefits. However, research to date is at high risk of bias, and randomized control trials are desperately needed to determine the efficacy and safety of this therapeutic option.

Convalescent Plasma Therapy for COVID-19: State of the Art

Convalescent plasma (CP) therapy has been used since the early 1900s to treat emerging infectious diseases; its efficacy was later associated with the evidence that polyclonal neutralizing antibodies can reduce the duration of viremia. Recent large outbreaks of viral diseases for which effective antivirals or vaccines are still lacking has renewed the interest in CP as a life-saving treatment. The ongoing COVID-19 pandemic has led to the scaling up of CP therapy to unprecedented levels. Compared with historical usage, pathogen reduction technologies have now added an extra layer of safety to the use of CP, and new manufacturing approaches are being explored. This review summarizes historical settings of application, with a focus on betacoronaviruses, and surveys current approaches for donor selection and CP collection, pooling technologies, pathogen inactivation systems, and banking of CP. We additionally list the ongoing registered clinical trials for CP throughout the world and discuss the trial results published thus far.