Early but not late convalescent plasma is associated with better survival in moderate-to-severe COVID-19

Rates Among Hospitalized Patients With COVID-19 Treated With Convalescent Plasma: A Systematic Review and Meta-Analysis

Objective

To examine the association of COVID-19 convalescent plasma transfusion with mortality and the differences between subgroups in hospitalized patients with COVID-19.

Patients and Methods

On October 26, 2022, a systematic search was performed for clinical studies of COVID-19 convalescent plasma in the literature from January 1, 2020, to October 26, 2022. Randomized clinical trials and matched cohort studies investigating COVID-19 convalescent plasma transfusion compared with standard of care treatment or placebo among hospitalized patients with confirmed COVID-19 were included. The electronic search yielded 3841 unique records, of which 744 were considered for full-text screening. The selection process was performed independently by a panel of 5 reviewers. The study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Data were extracted by 5 independent reviewers in duplicate and pooled using an inverse-variance random effects model. The prespecified end point was all-cause mortality during hospitalization.

Results

Thirty-nine randomized clinical trials enrolling 21,529 participants and 70 matched cohort studies enrolling 50,160 participants were included in the systematic review. Separate meta-analyses reported that transfusion of COVID-19 convalescent plasma was associated with a decrease in mortality compared with the control cohort for both randomized clinical trials (odds ratio [OR], 0.87; 95% CI, 0.76-1.00) and matched cohort studies (OR, 0.76; 95% CI, 0.66-0.88). The meta-analysis of subgroups revealed 2 important findings. First, treatment with convalescent plasma containing high antibody levels was associated with a decrease in mortality compared with convalescent plasma containing low antibody levels (OR, 0.85; 95% CI, 0.73 to 0.99). Second, earlier treatment with COVID-19 convalescent plasma was associated with a decrease in mortality compared with the later treatment cohort (OR, 0.63; 95% CI, 0.48 to 0.82).

Conclusion

During COVID-19 convalescent plasma use was associated with a 13% reduced risk of mortality, implying a mortality benefit for hospitalized patients with COVID-19, particularly those treated with convalescent plasma containing high antibody levels treated earlier in the disease course.

Reduced Mortality among COVID-19 ICU Patients after Treatment with HemoClear Convalescent Plasma in Suriname

Convalescent plasma is a promising therapy for coronavirus disease 2019 (COVID-19), but its efficacy in intensive care unit (ICU) patients in low- and middle-income country settings such as Suriname is unknown. Bedside plasma separation using the HemoClear device made convalescent plasma therapy accessible as a treatment option in Suriname. Two hundred patients with severe SARS-CoV-2 infection requiring intensive care were recruited. Fifty eight patients (29%) received COVID-19 convalescent plasma (CCP) treatment in addition to standard of care (SOC). The CCP treatment and SOC groups were matched by age, sex, and disease severity scores. Mortality in the CCP treatment group was significantly lower than that in the SOC group (21% versus 39%; Fisher's exact test P = 0.0133). Multivariate analysis using ICU days showed that CCP treatment reduced mortality (hazard ratio [HR], 0.35; 95% confidence interval [CI], 0.18 to 0.66; P = 0.001), while complication of acute renal failure (creatinine levels, >110 mol/L; HR, 4.45; 95% CI, 2.54 to 7.80; P < 0.0001) was independently associated with death. Decrease in chest X-ray score in the CCP treatment group (median -3 points, interquartile range [IQR] -4 to -1) was significantly greater than that in the SOC group (median -1 point, IQR -3 to 1, Mann-Whitney test P = 0.0004). Improvement in the PaO₂/FiO₂ ratio was also significantly greater in the CCP treatment group (median 83, IQR 8 to 140) than in the SOC group (median 35, IQR -3 to 92, Mann-Whitney P = 0.0234). Further research is needed for HemoClear-produced CCP as a therapy for SARS-CoV-2 infection together with adequately powered, randomized controlled trials. IMPORTANCE This study compares mortality and other endpoints between intensive care unit COVID-19 patients treated with convalescent plasma plus standard of care (CCP), and a control group of patients hospitalized in the same medical ICU facility treated with standard of care alone (SOC) in a low- and middle-income country (LMIC) setting using bedside donor whole blood separation by gravity (HemoClear) to produce the CCP. It demonstrates a significant 65% survival improvement in HemoClear-produced CCP recipients (HR, 0.35; 95% CI, 0.19 to 0.66; P = 0.001). Although this is an exploratory study, it clearly shows the benefit of using the HemoClear-produced CCP in ICU patients in the Suriname LMIC setting. Additional studies could further substantiate our findings and their applicability for both LMICs and high-income countries and the use of CCP as a prepared readiness method to combat new viral pandemics.

Inflammatory markers and auto-Abs to type I IFNs in COVID-19 convalescent plasma cohort study

BACKGROUND

COVID-19 convalescent plasma (CCP) contains neutralising anti-SARS-CoV-2 antibodies that may be useful as COVID-19 passive immunotherapy in patients at risk of developing severe disease. Such plasma from convalescent patients may also have additional immune-modulatory properties when transfused to COVID-19 patients.

METHODS

CCP (n = 766) was compared to non-convalescent control plasma (n = 166) for soluble inflammatory markers, ex-vivo inflammatory bioactivity on endothelial cells, neutralising auto-Abs to type I IFNs and reported adverse events in the recipients.

FINDINGS

CCP exhibited a statistically significant increase in IL-6 and TNF-alpha levels (0.531 ± 0.04 vs 0.271 ± 0.04; (95% confidence interval [CI], 0.07371-0.4446; p = 0.0061) and 0.900 ± 0.07 vs 0.283 ± 0.07 pg/mL; (95% [CI], 0.3097-0.9202; p = 0.0000829) and lower IL-10 (0.731 ± 0.07 vs 1.22 ± 0.19 pg/mL; (95% [CI], -0.8180 to -0.1633; p = 0.0034) levels than control plasma. Neutralising auto-Abs against type I IFNs were detected in 14/766 (1.8%) CCPs and were not associated with reported adverse events when transfused. Inflammatory markers and bioactivity in CCP with or without auto-Abs, or in CCP whether or not linked to adverse events in transfused patients, did not differ to a statistically significant extent.

INTERPRETATION

Overall, CCP exhibited moderately increased inflammatory markers compared to the control plasma with no discernible differences in ex-vivo bioactivity. Auto-Abs to type I IFNs detected in a small fraction of CCP were not associated with reported adverse events or differences in inflammatory markers. Additional studies, including careful clinical evaluation of patients treated with CCP, are required in order to further define the clinical relevance of these findings.

FUNDING

French National Blood Service-EFS, the Association "Les Amis de Rémi" Savigneux, France, the "Fondation pour la Recherche Médicale (Medical Research Foundation)-REACTing 2020".

COVID-19 Convalescent Plasma and Clinical Trials: Understanding Conflicting Outcomes

Convalescent plasma (CP) recurs as a frontline treatment in epidemics because it is available as soon as there are survivors. The COVID-19 pandemic represented the first large-scale opportunity to shed light on the mechanisms of action, safety, and efficacy of CP using modern evidence-based medicine approaches. Studies ranging from observational case series to randomized controlled trials (RCTs) have reported highly variable efficacy results for COVID-19 CP (CCP), resulting in uncertainty. We analyzed variables associated with efficacy, such as clinical settings, disease severity, CCP SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) antibody levels and function, dose, timing of administration (variously defined as time from onset of symptoms, molecular diagnosis, diagnosis of pneumonia, or hospitalization, or by serostatus), outcomes (defined as hospitalization, requirement for ventilation, clinical improvement, or mortality), CCP provenance and time for collection, and criteria for efficacy. The conflicting trial results, along with both recent WHO guidelines discouraging CCP usage and the recent expansion of the FDA emergency use authorization (EUA) to include outpatient use of CCP, create confusion for both clinicians and patients about the appropriate use of CCP. A review of 30 available RCTs demonstrated that signals of efficacy (including reductions in mortality) were more likely if the CCP neutralizing titer was >160 and the time to randomization was less than 9 days. The emergence of the Omicron variant also reminds us of the benefits of polyclonal antibody therapies, especially as a bridge to the development and availability of more specific therapies.

Decrease in Angiotensin-Converting Enzyme activity but not concentration in plasma/lungs in COVID-19 patients offers clues for diagnosis/treatment

Although several therapeutics are used to treat coronavirus disease 2019 (COVID-19) patients, there is still no definitive metabolic marker to evaluate disease severity and recovery or a quantitative test to end quarantine. Because severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infects human cells via the angiotensin-converting-enzyme 2 (ACE2) receptor and COVID-19 is associated with renin-angiotensin system dysregulation, we evaluated soluble ACE2 (sACE2) activity in the plasma/saliva of 80 hospitalized COVID-19 patients and 27 non-COVID-19 volunteers, and levels of ACE2/Ang (1-7) in plasma or membrane (mACE2) in lung autopsy samples. sACE2 activity was markedly reduced (p < 0.0001) in COVID-19 plasma (n = 59) compared with controls (n = 27). Nadir sACE2 activity in early hospitalization was restored during disease recovery, irrespective of patient age, demographic variations, or comorbidity; in convalescent plasma-administered patients (n = 45), restoration was statistically higher than matched controls (n = 22, p = 0.0021). ACE2 activity was also substantially reduced in the saliva of COVID-19 patients compared with controls (p = 0.0065). There is a strong inverse correlation between sACE2 concentration and sACE2 activity and Ang (1-7) levels in participant plasmas. However, there were no difference in membrane ACE2 levels in lungs of autopsy tissues of COVID-19 (n = 800) versus other conditions (n = 300). These clinical observations suggest sACE2 activity as a potential biomarker and therapeutic target for COVID-19.

COVID-19 and vaccination: myths vs science

INTRODUCTION

Several vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been developed since the inception of the coronavirus disease 2019 (COVID-19) in December 2019, at unprecedented speed. However, these rapidly developed vaccines raised many questions related to the efficacy and safety of vaccines in different communities across the globe. Various hypotheses regarding COVID-19 and its vaccines were generated, and many of them have also been answered with scientific evidence. Still, there are many myths/misinformation related to COVID-19 and its vaccines, which create hesitancy for COVID-19 vaccination, and must be addressed critically to achieve success in the battle against the pandemic.

AREA COVERED

The development of anti-SARS-CoV-2 vaccines against COVID-19, their safety and efficacy, and myths/misinformation relating to COVID-19 and vaccines are presented.

EXPERT OPINION

In this pandemic we have seen a global collaborative effort of researchers, governments, and industry, supported by billions of dollars in funding, have allowed the development of vaccines far more quickly than in the past. Vaccines go through rigorous testing, analysis, and evaluations in clinical settings prior to their approval, even if they are approved for emergency use. Despite the myths, vaccination represents an important strategy to get back to normality.

Post-trial follow-up after a randomized clinical trial of COVID-19 convalescent plasma

Background: COVID-19 convalescent plasma (CP) proved to be a safe acute intervention, however, the long-term clinical effects of COVID-19 CP are to date unknown. CP might have a prospective negative effect by down-regulating the inflammatory response suppressing antibody formation and promoting autoantibodies against interferons. Our objective was to establish the long-term safety profile of COVID-19 CP and determine if its administration increases the risk for further respiratory infections in older adults. Methods: All participants included in the intention to treat analysis of a randomized clinical trial evaluating the efficacy of COVID-19 CP in older adults were invited to participate in this post-trial follow-up study. Patients were strictly followed for at least 6 months after randomization. The primary endpoint was the number of patients with clinically confirmed acute respiratory infections (ARIs). Secondary endpoints included all-cause mortality, time to first respiratory infection, SARS-CoV-2 re-infection, adverse events, and persistence of COVID-19 symptoms after initial infection. Results: 142 patients were included in the study (total retention rate=92.8%). The mean age was 77.2 years (SD=8.6) and the median duration of follow-up was 10.4 months (IQR=1.63), with no differences among groups. 20 patients had a clinically confirmed ARI during the study. No differences were observed between groups in the proportion of ARIs (CP=11/72 and Placebo=9/70, p-value=0.678) and in the probability of ARI-free survival between groups (log-rank test p-value=0.63). No differences emerged when comparing groups regarding secondary endpoints. Conclusions: COVID-19 convalescent plasma remains a safe intervention without increasing the risk of acute respiratory infection or other clinical consequences in the long term.

Recent advances in passive immunotherapies for COVID-19: The Evidence-Based approaches and clinical trials

In late 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged, causing a global pandemic called COVID-19. Currently, there is no definitive treatment for this emerging disease. Global efforts resulted in developing multiple platforms of COVID-19 vaccines, but their efficacy in humans should be wholly investigated in the long-term clinical and epidemiological follow-ups. Despite the international efforts, COVID-19 vaccination accompanies challenges, including financial and political obstacles, serious adverse effects (AEs), the impossibility of using vaccines in certain groups of people in the community, and viral evasion due to emerging novel variants of SARS-CoV-2 in many countries. For these reasons, passive immunotherapy has been considered a complementary remedy and a promising way to manage COVID-19. These approaches arebased on reduced inflammation due to inhibiting cytokine storm phenomena, immunomodulation,preventing acute respiratory distress syndrome (ARDS), viral neutralization, anddecreased viral load. This article highlights passive immunotherapy and immunomodulation approaches in managing and treating COVID-19 patients and discusses relevant clinical trials (CTs).

Early administration of COVID-19 convalescent plasma with high titer antibody content by live viral neutralization assay is associated with modest clinical efficacy

The efficacy of COVID‐19 convalescent plasma (CCP) as a treatment for hospitalized patients with COVID‐19 remains somewhat controversial; however, many studies have not evaluated CCP documented to have high neutralizing antibody titer by a highly accurate assay. To evaluate the correlation of the administration of CCP with titer determined by a live viral neutralization assay with 7‐ and 28‐day death rates during hospitalization, a total of 23 118 patients receiving a single unit of CCP were stratified into two groups: those receiving high titer CCP (>250 50% inhibitory dilution, ID50; n = 13 636) or low titer CCP (≤250 ID50; n = 9482). Multivariable Cox regression was performed to assess risk factors. Non‐intubated patients who were transfused with high titer CCP showed 1.1% and 1.7% absolute reductions in overall 7‐ and 28‐day death rates, respectively, compared to those non‐intubated patients receiving low titer CCP. No benefit of CCP was observed in intubated patients. The relative benefit of high titer CCP was confirmed in multivariable Cox regression. Administration of CCP with high titer antibody content determined by live viral neutralization assay to non‐intubated patients is associated with modest clinical efficacy. Although shown to be only of modest clinical benefit, CCP may play a role in the future should viral variants develop that are not neutralized by other available therapeutics.

High-dose vitamin D versus placebo to prevent complications in COVID-19 patients: Multicentre randomized controlled clinical trial

Background

The role of oral vitamin D₃ supplementation for hospitalized patients with COVID-19 remains to be determined. The study was aimed to evaluate whether vitamin D₃ supplementation could prevent respiratory worsening among hospitalized patients with COVID-19.

Methods and findings

We designed a multicentre, randomized, double-blind, sequential, placebo-controlled clinical trial. The study was conducted in 17 second and third level hospitals, located in four provinces of Argentina, from 14 August 2020 to 22 June 2021. We enrolled 218 adult patients, hospitalized in general wards with SARS-CoV-2 confirmed infection, mild-to-moderate COVID-19 and risk factors for disease progression. Participants were randomized to a single oral dose of 500 000 IU of vitamin D₃ or matching placebo. Randomization ratio was 1:1, with permuted blocks and stratified for study site, diabetes and age (≤60 vs >60 years). The primary outcome was the change in the respiratory Sepsis related Organ Failure Assessment score between baseline and the highest value recorded up to day 7. Secondary outcomes included the length of hospital stay; intensive care unit admission; and in-hospital mortality. Overall, 115 participants were assigned to vitamin D₃ and 105 to placebo (mean [SD] age, 59.1 [10.7] years; 103 [47.2%] women). There were no significant differences in the primary outcome between groups (median [IQR] 0.0 [0.0–1.0] vs 0.0 [0.0–1.0], for vitamin D₃ and placebo, respectively; p = 0.925). Median [IQR] length of hospital stay was not significantly different between vitamin D₃ group (6.0 [4.0–9.0] days) and placebo group (6.0 [4.0–10.0] days; p = 0.632). There were no significant differences for intensive care unit admissions (7.8% vs 10.7%; RR 0.73; 95% CI 0.32 to 1.70; p = 0.622), or in-hospital mortality (4.3% vs 1.9%; RR 2.24; 95% CI 0.44 to 11.29; p = 0.451). There were no significant differences in serious adverse events (vitamin D₃ = 14.8%, placebo = 11.7%).

Conclusions

Among hospitalized patients with mild-to-moderate COVID-19 and risk factors, a single high oral dose of vitamin D₃ as compared with placebo, did not prevent the respiratory worsening.

Trial registration

ClincicalTrials.gov Identifier: NCT04411446.

Timing of convalescent plasma administration and 28-day mortality in COVID-19 pneumonia

This is a multicenter cohort study including consecutive, hospitalized patients ≥18 years, with moderate to severe COVID-19, carried out to evaluate the relationship between the timing of convalescent plasma administration and 28-day mortality. Data were prospectively collected between May 14, 2020 and October 31, 2020. Patients were grouped according to the timing of administration of convalescent plasma as <3 days, between 3 and 7 days, and >7 days. The main outcome variable was 28-day mortality. Independent predictors of mortality were identified by logistic regression. Of 4719 patients receiving convalescent plasma, 3036 (64.3%) were in the general ward, 1171 (24.8%) in the intensive care unit (ICU), and 512 (10.8%) in the ICU on mechanical ventilation. Convalescent plasma was administered to 3113 (66%) patients within the first 3 days of hospital admission, to 1380 (29.2%) between 3 and 7 days, and to 226 after 7 days; 28-day mortality was, respectively, 18.1%, 30.4% and 38.9% (p<0.001). In the regression model, convalescent plasma administration within the first 3 days of admission was associated with reduced 28-day mortality, compared with the administration after 7 days (OR 0.40, 95% CI 0.30 to 0.53). Early convalescent plasma administration was associated to a significant decreased mortality in patients in the general ward (OR 0.45, 95% CI 0.29 to 0.69) and in the ICU (OR 0.35, 95% CI 0.19 to 0.64), but not in those requiring mechanical ventilation (OR 0.52, 95% CI 0.27 to 1.01). In conclusion, this study suggests that early administration of convalescent plasma to patients with COVID-19 pneumonia is critical to obtain therapeutic benefit.

Effect of Convalescent Plasma therapy on Mortality in Moderate-to-Severely Ill COVID-19 Patients

Introduction

The role of plasma therapy in the management of the COVID-19, pandemic has been speculated. However, in view of the varied response regarding its effectiveness from various multicenter studies, there is a need to conduct more single center population-specific studies. We, thus, aimed to assess the role of convalescent plasma therapy in COVID-19 patient management in a single -center.

Methods

This retrospective study was conducted using records of all COVID-19 patients who received plasma therapy over a period of 6 months in a dedicated COVID-19 hospital in Delhi. Information pertaining to transfusion, disease severity, associated comorbidities, the treatment given and patient outcome were recorded. Data was analyzed using SPSSv23.

Results

Of the141 patients who received plasma therapy, 62% were discharged after treatment. Mortality was found to be significantly higher in patients > 60 years of age (p < 0.001), those with severe COVID-19 infection (p < 0.05) and pre-existing renal disease (p < 0.05). The admission-transfusion interval was significantly correlated to mortality and was a sensitive parameter for predicting outcome at cut off value of < 5 days (p < 0.001). There was no significant association of mortality with patient blood group, plasma antibody levels or donor hemoglobin levels.

Conclusions

We report improvement and recovery in a large number of patients who received convalescent plasma within the first 5 days of hospitalization with moderate to severe disease. Further research to compare dosage and administration protocols to delineate role of CCP in survival of COVID-19 patients is needed before it is

prematurely shelved.

Efficacy and Safety of COVID-19 Convalescent Plasma in Hospitalized Patients: A Randomized Clinical Trial

IMPORTANCE

There is clinical equipoise for COVID-19 convalescent plasma (CCP) use in patients hospitalized with COVID-19.

OBJECTIVE

To determine the safety and efficacy of CCP compared with placebo in hospitalized patients with COVID-19 receiving noninvasive supplemental oxygen.

DESIGN, SETTING, AND PARTICIPANTS

CONTAIN COVID-19, a randomized, double-blind, placebo-controlled trial of CCP in hospitalized adults with COVID-19, was conducted at 21 US hospitals from April 17, 2020, to March 15, 2021. The trial enrolled 941 participants who were hospitalized for 3 or less days or presented 7 or less days after symptom onset and required noninvasive oxygen supplementation.

INTERVENTIONS

A unit of approximately 250 mL of CCP or equivalent volume of placebo (normal saline).

MAIN OUTCOMES AND MEASURES

The primary outcome was participant scores on the 11-point World Health Organization (WHO) Ordinal Scale for Clinical Improvement on day 14 after randomization; the secondary outcome was WHO scores determined on day 28. Subgroups were analyzed with respect to age, baseline WHO score, concomitant medications, symptom duration, CCP SARS-CoV-2 titer, baseline SARS-CoV-2 serostatus, and enrollment quarter. Outcomes were analyzed using a bayesian proportional cumulative odds model. Efficacy of CCP was defined as a cumulative adjusted odds ratio (cOR) less than 1 and a clinically meaningful effect as cOR less than 0.8.

RESULTS

Of 941 participants randomized (473 to placebo and 468 to CCP), 556 were men (59.1%); median age was 63 years (IQR, 52-73); 373 (39.6%) were Hispanic and 132 (14.0%) were non-Hispanic Black. The cOR for the primary outcome adjusted for site, baseline risk, WHO score, age, sex, and symptom duration was 0.94 (95% credible interval [CrI], 0.75-1.18) with posterior probability (P[cOR<1] = 72%); the cOR for the secondary adjusted outcome was 0.92 (95% CrI, 0.74-1.16; P[cOR<1] = 76%). Exploratory subgroup analyses suggested heterogeneity of treatment effect: at day 28, cORs were 0.72 (95% CrI, 0.46-1.13; P[cOR<1] = 93%) for participants enrolled in April-June 2020 and 0.65 (95% CrI, 0.41 to 1.02; P[cOR<1] = 97%) for those not receiving remdesivir and not receiving corticosteroids at randomization. Median CCP SARS-CoV-2 neutralizing titer used in April to June 2020 was 1:175 (IQR, 76-379). Any adverse events (excluding transfusion reactions) were reported for 39 (8.2%) placebo recipients and 44 (9.4%) CCP recipients (P = .57). Transfusion reactions occurred in 2 (0.4) placebo recipients and 8 (1.7) CCP recipients (P = .06).

CONCLUSIONS AND RELEVANCE

In this trial, CCP did not meet the prespecified primary and secondary outcomes for CCP efficacy. However, high-titer CCP may have benefited participants early in the pandemic when remdesivir and corticosteroids were not in use.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04364737.

A phase 2 single center open label randomised control trial for convalescent plasma therapy in patients with severe COVID-19

A single center open label phase 2 randomised control trial (Clinical Trial Registry of India No. CTRI/2020/05/025209) was done to assess clinical and immunological benefits of passive immunization using convalescent plasma therapy. At the Infectious Diseases and Beleghata General Hospital in Kolkata, India, 80 patients hospitalized with severe COVID-19 disease and fulfilling the inclusion criteria (aged more than 18 years, with either mild ARDS having PaO2/FiO2 200-300 or moderate ARDS having PaO2/FiO2 100-200, not on mechanical ventilation) were recruited and randomized into either standard of care (SOC) arm (N = 40) or the convalescent plasma therapy (CPT) arm (N = 40). Primary outcomes were all-cause mortality by day 30 of enrolment and immunological correlates of response to therapy if any, for which plasma abundance of a large panel of cytokines was quantitated before and after intervention to assess the effect of CPT on the systemic hyper-inflammation encountered in these patients. The secondary outcomes were recovery from ARDS and time taken to negative viral RNA PCR as well as to report any adverse reaction to plasma therapy. Transfused convalescent plasma was characterized in terms of its neutralizing antibody content as well as proteome. The trial was completed and it was found that primary outcome of all-cause mortality was not significantly different among severe COVID-19 patients with ARDS randomized to two treatment arms (Mantel-Haenszel Hazard Ratio 0.6731, 95% confidence interval 0.3010-1.505, with a P value of 0.3424 on Mantel-Cox Log-rank test). No adverse effect was reported with CPT. In severe COVID-19 patients with mild or moderate ARDS no significant clinical benefit was registered in this clinical trial with convalescent plasma therapy in terms of prespecified outcomes.

Demographic and Clinical Factors Associated with Reactivity of Anti-SARS-CoV-2 Antibodies in Serbian Convalescent Plasma Donors

Passive immunotherapy with convalescent COVID-19 plasma (CCP) is used as a therapeutic procedure in many countries, including Serbia. In this study, we analyzed the association between demographic factors, COVID-19 severity and the reactivity of anti-SARS-CoV-2 antibodies (Abs) in Serbian CCP donors. Individuals (n = 468) recovered from confirmed SARS-CoV-2 infection, and who were willing to donate their plasma for passive immunization of COVID-19 patients were enrolled in the study. Plasma samples were tested for the presence of IgG reactive to SARS-CoV-2 spike glycoprotein (S1) and nucleocapsid antigens. Individuals were characterized according to age, gender, comorbidities, COVID-19 severity, ABO blood type and RhD factor. Total of 420 candidates (420/468; 89.74%) reached the levels of anti-SARS-CoV-2 IgG that qualified them for inclusion in CCP donation program. Further statistical analysis showed that male individuals (p = 0.034), older age groups (p < 0.001), existence of hypertension (p = 0.008), and severe COVID-19 (p = 0.000) are linked with higher levels of anti-SARS-CoV-2 Abs. These findings will guide the selection of CCP donors in Serbia. Further studies need to be conducted to assess the neutralization potency and clinical efficiency of CCP collected from Serbian donors with high anti-SARS-CoV-2 IgG reactivity.

The immunology and immunotherapy for COVID-19

The ongoing global pandemic of coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and significantly impacts the world economy and daily life. Symptoms of COVID-19 range from asymptomatic to fever, dyspnoea, acute respiratory distress and multiple organ failure. Critical cases often occur in the elderly and patients with pre-existing conditions. By binding to the angiotensin-converting enzyme 2 receptor, SARS-CoV-2 can enter and replicate in the host cell, exerting a cytotoxic effect and causing local and systemic inflammation. Currently, there is no specific treatment for COVID-19, and immunotherapy has consistently attracted attention because of its essential role in boosting host immunity to the virus and reducing overwhelming inflammation. In this review, we summarise the immunopathogenic features of COVID-19 and highlight recent advances in immunotherapy to illuminate ideas for the development of new potential therapies.

A randomized controlled study of convalescent plasma for individuals hospitalized with COVID-19 pneumonia

BackgroundAntibody-based strategies for COVID-19 have shown promise in prevention and treatment of early disease. COVID-19 convalescent plasma (CCP) has been widely used but results from randomized trials supporting its benefit in hospitalized patients with pneumonia are limited. Here, we assess the efficacy of CCP in severely ill, hospitalized adults with COVID-19 pneumonia.MethodsWe performed a randomized control trial (PennCCP2), with 80 adults hospitalized with COVID-19 pneumonia, comparing up to 2 units of locally sourced CCP plus standard care versus standard care alone. The primary efficacy endpoint was comparison of a clinical severity score. Key secondary outcomes include 14- and 28-day mortality, 14- and 28-day maximum 8-point WHO ordinal score (WHO8) score, duration of supplemental oxygenation or mechanical ventilation, respiratory SARS-CoV-2 RNA, and anti-SARS-CoV-2 antibodies.ResultsEighty hospitalized adults with confirmed COVID-19 pneumonia were enrolled at median day 6 of symptoms and day 1 of hospitalization; 60% were anti-SARS-CoV-2 antibody seronegative. Participants had a median of 3 comorbidities, including risk factors for severe COVID-19 and immunosuppression. CCP treatment was safe and conferred significant benefit by clinical severity score (median [MED] and interquartile range [IQR] 10 [5.5-30] vs. 7 [2.75-12.25], P = 0.037) and 28-day mortality (n = 10, 26% vs. n = 2, 5%; P = 0.013). All other prespecified outcome measures showed weak evidence toward benefit of CCP.ConclusionTwo units of locally sourced CCP administered early in hospitalization to majority seronegative participants conferred a significant benefit in clinical severity score and 28-day mortality. Results suggest CCP may benefit select populations, especially those with comorbidities who are treated early.Trial RegistrationClinicalTrials.gov NCT04397757.FundingUniversity of Pennsylvania.

Is SARS-CoV-2 viral clearance in nasopharyngeal swabs an appropriate surrogate marker for clinical efficacy of neutralising antibody-based therapeutics?

Viral clearance is likely the best way to assess the efficacy of antibody-based therapies. Although antibodies can mediate a variety of effects that include modulation of inflammation, the demonstration of viral clearance provides an accessible and measurable parameter that can be used to evaluate efficacy and determine dosing. Therefore, it is important to ascertain the ability of monoclonal antibodies and convalescent plasma to effect viral clearance. For COVID-19, which is caused by the respiratory virus SARS-CoV-2, the most common assay to assess viral clearance is via a nasopharyngeal swab (NPS). However, assessment of antibody efficacy by sampling this site may be misleading because it may not be as accessible to serum antibodies as respiratory secretions or circulating blood. Adding to the complexity of assessing the efficacy of administered antibody, particularly in randomised controlled trials (RCTs) that enroled patients at different times after the onset of COVID-19 symptoms, viral clearance may also be mediated by endogenous antibody. In this article we critically review available data on viral clearance in RCTs, matched control studies, case series and case reports of antibody therapies in an attempt to identify variables that contribute to antibody efficacy and suggest optimal strategies for future studies.

Convalescent Plasma-A Light at the End of the Tunnel: A Systematic Review and Meta-analysis of Randomized Controlled Trials

In the absence of a definitive therapy during this ongoing unprecedented crisis, coronavirus disease-2019 (COVID-19) pandemic, convalescent plasma transfusion (CPT) has shown some promising results. This review summarizes the existing evidence of the efficacy of CPT in COVID-19 patients based upon scientific publications to date. We have included only the randomized controlled trials (RCTs) through an extensive screening of electronic databases up to July 31, 2021. In 19 RCTs, with a total of 16,476 COVID-19 patients we found low-quality evidence of significant reduction in mortality (odds ratio (OR) = 0.80; 95% confidence interval (CI): 0.66-0.96, I2 = 40%), better clinical outcome when applied <7 days (OR = 2.13, 95% CI 1.28-3.53, I2 = 0%), and improved viral clearance (OR = 2.6, 95% CI: 1.3-5.45, I2 = 74%). Meta-regression analysis found that as a covariate, intubation on admission (p = 0.007) had a significant impact. However, there was any significant reduction neither in duration for clinical improvement (MD = -0.79, 95% CI: -2.76-1.18, I2 = 98%), nor in total period of hospital stay (MD = 0.02, 95% CI: -0.75-0.78, I2 = 81%). Early application of CPT is still relevant in reducing morbidity and mortality in critically ill patients and is too early to write it off as a potential therapeutic modality for COVID-19 patients.

HOW TO CITE THIS ARTICLE

Sarkar S, Khanna P, Singh AK. Convalescent -Plasma-A Light at the End of the Tunnel: A Systematic Review and Meta-analysis of Randomized Controlled Trials. Indian J Crit Care Med 2021;25(11):1292-1300.