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

Double-blinded, randomised, placebo-controlled trial of convalescent plasma for COVID-19: analyses by neutralising antibodies homologous to recipients' variants

INTRODUCTION

Convalescent plasma (CP) emerged as potential treatment for COVID-19 early in the pandemic. While efficacy in hospitalised patients has been lacklustre, CP may be beneficial at the first stages of disease. Despite multiple new variants emerging, no trials have involved analyses on variant-specific antibody titres of CP.

METHODS

We recruited hospitalised COVID-19 patients within 10 days of symptom onset and, employing a double-blinded approach, randomised them to receive 200 ml convalescent plasma with high (HCP) or low (LCP) neutralising antibody (NAb) titre against the ancestral strain (Wuhan-like variant) or placebo in 1:1:1 ratio. Primary endpoints comprised intubation, corticosteroids for symptom aggravation, and safety assessed as serious adverse events. For a preplanned ad hoc analysis, the patients were regrouped by infused CP's NAb titers to variants infecting the recipients i.e. by titres of homologous HCP (hHCP) or LCP (hLCP).

RESULTS

Of the 57 patients, 18 received HCP, 19 LCP and 20 placebo, all groups smaller than planned. No significant differences were found for primary endpoints. In ad hoc analysis, hHCPrecipients needed significantly less respiratory support, and appeared to be given corticosteroids less frequently (1/14; 7.1%) than those receiving hLCP (9/23; 39.1%) or placebo (8/20; 40%), (p = 0.077).

DISCUSSION

Our double-blinded, placebo-controlled CP therapy trial remained underpowered and does not allow any firm conclusions for early-stage hospitalised COVID-19 patients. Interestingly, however, regrouping by homologous - recipients' variant-specific - CP titres suggested benefits for hHCP. We encourage similar re-analysis of ongoing/previous larger CP studies.

TRIAL REGISTRATION

ClinTrials.gov identifier: NCT0473040.

Blood Banking Capacity in Low-and Middle-Income Countries: Covid-19 Convalescent Plasma in Context

Blood transfusion capacity in low- and middle-income countries (LMICs), encompassing both the safety and adequacy of the blood supply, is limited. The challenges facing blood banks in LMICs include regulatory oversight, blood donor selection, collection procedures, laboratory testing, and post-transfusion surveillance. A high proportion of LMICs are unable to fully meet clinical demands for blood products, and many do not meet even the minimum threshold of collection (10 units per 1000 population). Suboptimal clinical transfusion practices, in large part due to a lack of training in transfusion medicine, contribute to blood wastage. During the COVID-19 pandemic, high- and LMICs alike experienced blood shortages, in large part due to quarantine and containment measures that impeded donor mobility. COVID-19 convalescent plasma (CCP) was particularly appealing for the treatment of patients with COVID-19 in LMICs, as it is a relatively inexpensive intervention and makes use of the existing blood collection infrastructure. Nonetheless, the challenges of using CCP in LMICs need to be contextualized among broad concerns surrounding blood safety and availability. Specifically, reliance on first time, family replacement and paid donors, coupled with deficient infectious disease testing and quality oversight, increase the risk of transfusion transmitted infections from CCP in LMICs. Furthermore, many LMICs are unable to meet general transfusion needs; therefore, CCP collection also risked exacerbation of pervasive blood shortages.

COVID-19 therapeutics

SUMMARYSince the emergence of COVID-19 in 2020, an unprecedented range of therapeutic options has been studied and deployed. Healthcare providers have multiple treatment approaches to choose from, but efficacy of those approaches often remains controversial or compromised by viral evolution. Uncertainties still persist regarding the best therapies for high-risk patients, and the drug pipeline is suffering fatigue and shortage of funding. In this article, we review the antiviral activity, mechanism of action, pharmacokinetics, and safety of COVID-19 antiviral therapies. Additionally, we summarize the evidence from randomized controlled trials on efficacy and safety of the various COVID-19 antivirals and discuss unmet needs which should be addressed.

Immunoadsorption as a method of antibody donation during the COVID-19 pandemic

BACKGROUND AND OBJECTIVES

Initial therapeutic efforts to treat severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) included the use of plasma from convalescent donors containing anti-SARS-CoV-2 antibodies. High-neutralizing antibody titres are required for therapeutic efficacy. This study aims to show that immunoadsorption followed by tangential flow filtration can be used to obtain antibody concentrates with high-neutralizing capacities.

MATERIALS AND METHODS

Eligible donors (n = 10, five males and three females) underwent immunoadsorption using adsorber columns specific for human antibodies. Glycine-washed out eluates of 1.5 L volume were further concentrated by tangential flow filtration using 30 kDa ultrafiltration membranes. The same membranes were applied for diafiltrations to exchange residual glycine for 0.9% normal saline.

RESULTS

Antibody concentrates were obtained within 8 h from the start of donation and had 4.58 ± 1.95, 3.28 ± 1.28 and 2.02 ± 0.92 times higher total IgG, IgA and IgM concentrations, 3.29 ± 1.62 and 3.74 ± 0.6 times higher SARS-CoV-2 N and S antibody concentrations and 3.85 ± 1.71 times higher SARS-CoV-2 S-specific IgG concentrations compared to the donors' peripheral blood. The specific SARS-CoV-2 virus neutralization capacities increased in all but one concentrate. All antibody concentrates (50-70 mL final volume) passed microbiological tests, were free of hazardous glycine levels and could be stored at -80°C and 4°C for 1 year with 20 ± 3% antibody loss.

CONCLUSION

Immunoadsorption followed by tangential flow filtration is a feasible procedure to collect IgG, IgA and IgM as well as SARS-CoV-2 N- and S-specific antibody concentrates of low volume, free of albumin and coagulation factors. Whether these concentrates can be used as passive immunisation in infected patients remains to be elucidated.

Passive immunotherapies for the next influenza pandemic

Influenzavirus is among the most relevant candidates for a next pandemic. We review here the phylogeny of former influenza pandemics, and discuss candidate lineages. After briefly reviewing the other existing antiviral options, we discuss in detail the evidences supporting the efficacy of passive immunotherapies against influenzavirus, with a focus on convalescent plasma.

Next-generation treatments: Immunotherapy and advanced therapies for COVID-19

The COVID-19 pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), emerged in 2019 following prior outbreaks of coronaviruses like SARS and MERS in recent decades, underscoring their high potential of infectivity in humans. Insights from previous outbreaks of SARS and MERS have played a significant role in developing effective strategies to mitigate the global impact of SARS-CoV-2. As of January 7, 2024, there have been 774,075,242 confirmed cases of COVID-19 worldwide. To date, 13.59 billion vaccine doses have been administered, and there have been 7,012,986 documented fatalities (https://www.who.int/) Despite significant progress in addressing the COVID-19 pandemic, the rapid evolution of SARS-CoV-2 challenges human defenses, presenting ongoing global challenges. The emergence of new SARS-CoV-2 lineages, shaped by mutation and recombination processes, has led to successive waves of infections. This scenario reveals the need for next-generation vaccines as a crucial requirement for ensuring ongoing protection against SARS-CoV-2. This demand calls for formulations that trigger a robust adaptive immune response without leading the acute inflammation linked with the infection. Key mutations detected in the Spike protein, a critical target for neutralizing antibodies and vaccine design -specifically within the Receptor Binding Domain region of Omicron variant lineages (B.1.1.529), currently dominant worldwide, have intensified concerns due to their association with immunity evasion from prior vaccinations and infections. As the world deals with this evolving threat, the narrative extends to the realm of emerging variants, each displaying new mutations with implications that remain largely misunderstood. Notably, the JN.1 Omicron lineage is gaining global prevalence, and early findings suggest it stands among the immune-evading variants, a characteristic attributed to its mutation L455S. Moreover, the detrimental consequences of the novel emergence of SARS-CoV-2 lineages bear a particularly critical impact on immunocompromised individuals and older adults. Immunocompromised individuals face challenges such as suboptimal responses to COVID-19 vaccines, rendering them more susceptible to severe disease. Similarly, older adults have an increased risk of severe disease and the presence of comorbid conditions, find themselves at a heightened vulnerability to develop COVID-19 disease. Thus, recognizing these intricate factors is crucial for effectively tailoring public health strategies to protect these vulnerable populations. In this context, this review aims to describe, analyze, and discuss the current progress of the next-generation treatments encompassing immunotherapeutic approaches and advanced therapies emerging as complements that will offer solutions to counter the disadvantages of the existing options. Preliminary outcomes show that these strategies target the virus and address the immunomodulatory responses associated with COVID-19. Furthermore, the capacity to promote tissue repair has been demonstrated, which can be particularly noteworthy for immunocompromised individuals who stand as vulnerable actors in the global landscape of coronavirus infections. The emerging next-generation treatments possess broader potential, offering protection against a wide range of variants and enhancing the ability to counter the impact of the constant evolution of the virus. Furthermore, advanced therapies are projected as potential treatment alternatives for managing Chronic Post-COVID-19 syndromeand addressing its associated long-term complications.

Factors associated with the SARS-CoV-2 immunoglobulin-G titer levels in convalescent whole-blood donors: a Chinese cross-sectional study

Blood transfusions from convalescent Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infected patients could be used to treat patients with severe infections or immunocompromised patients. However, it is necessary to select the optimal donors to maximize the utilization of resources. In this study, we investigated the associations among body mass index (BMI), tobacco smoking, exercise frequency and duration, and alcohol consumption with the SARS-CoV-2 immunoglobulin-G (IgG) antibody titer levels with in the Chinese convalescent blood donor population. Here we show that BMI, smoking habits, and exercise frequency appear to be predictive factors for IgG levels in convalescent male blood donors. However, these variables were not observed as predictive of IgG levels in female convalescent blood donors. The findings could be used to optimize the screening for potential blood donors to treat immunocompromised or severely ill COVID-19 patients.

Experiences in the use of multiple doses of convalescent plasma in critically ill patients with COVID-19: An early phase 1 descriptive study

Background

At the beginning of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, transfusion of coronavirus disease 2019 (COVID-19) convalescent plasma (CCP) emerged as a potential therapeutic strategy to help patients severely afflicted by COVID-19. The efficacy of CCP has been controversial as it depends on many variables pertaining to the plasma donor and the patient with COVID-19, for example, time of convalescence or symptoms onset. This feasibility and descriptive study aimed to assess the safety of multiple doses of CCP in mechanically ventilated, intubated patients with respiratory failure due to COVID-19.

Methods

A cohort of 30 patients all experiencing severe respiratory failure and undergoing invasive mechanical ventilation in an intensive care unit, received up to five doses of 300-600 mL of CCP on alternate days (0, 2, 4, 6, and 8) until extubation, futility, or death.

Results

Nineteen patients received five doses, seven received four, and four received two or three doses. At 28-day follow-up mark, 57% of patients recovered and were sent home, and the long-term mortality rate was 27%. Ten severe adverse events reported in the study were unrelated to CCP transfusion. Independent of the number of transfused doses, most patients had detectable levels of total and neutralizing antibodies in plasma.

Conclusion

This study suggests that transfusion of multiple doses of CCP is safe. This strategy may represent a viable option for future studies, given the potential benefit of CCP transfusions during the early stages of infection in unvaccinated populations and in settings where monoclonal antibodies or antivirals are contraindicated or unavailable.

Hyperimmune Plasma and Immunoglobulins against COVID-19: A Narrative Review

Since late 2019, the new SARS-CoV-2 virus belonging to the Coronaviridae family has been responsible for COVID-19 pandemic, a severe acute respiratory syndrome. Several antiviral therapies, mostly derived from previous epidemics, were initially repurposed to fight this not rarely life-threatening respiratory illness. Among them, however, the only specific antibody-based therapy available against SARS-CoV-2 infection during the first year of the pandemic was represented by COVID-19 convalescent plasma (CCP). CCP, collected from recovered individuals, contains high levels of polyclonal antibodies of different subclasses able to neutralize SARS-CoV-2 infection. Tens of randomized controlled trials have been conducted during the last three years of the pandemic to evaluate the safety and the clinical efficacy of CCP in both hospitalized and ambulatory COVID-19 patients, whose main results will be summarized in this narrative review. In addition, we will present the current knowledge on the development of anti-SARS-CoV-2 hyperimmune polyclonal immunoglobulins.

Antibody and B Cell Responses to SARS-CoV-2 Infection and Vaccination: The End of the Beginning

As the COVID-19 pandemic has evolved during the past years, interactions between human immune systems, rapidly mutating and selected SARS-CoV-2 viral variants, and effective vaccines have complicated the landscape of individual immunological histories. Here, we review some key findings for antibody and B cell-mediated immunity, including responses to the highly mutated omicron variants; immunological imprinting and other impacts of successive viral antigenic variant exposures on antibody and B cell memory; responses in secondary lymphoid and mucosal tissues and non-neutralizing antibody-mediated immunity; responses in populations vulnerable to severe disease such as those with cancer, immunodeficiencies, and other comorbidities, as well as populations showing apparent resistance to severe disease such as many African populations; and evidence of antibody involvement in postacute sequelae of infection or long COVID. Despite the initial phase of the pandemic ending, human populations will continue to face challenges presented by this unpredictable virus.

Vaccine-Boosted CCP Decreases Virus Replication and Hastens Resolution of Infection Despite Transiently Enhancing Disease in SARS-CoV-2-Infected Hamsters

Definitive data demonstrating the utility of coronavirus disease 2019 (COVID-19) convalescent plasma (CCP) for treating immunocompromised patients remains elusive. To better understand the mechanism of action of CCP, we studied viral replication and disease progression in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected hamsters treated with CCP obtained from recovered COVID-19 patients that were also vaccinated with an mRNA vaccine, hereafter referred to as Vaxplas. Vaxplas transiently enhanced disease severity and lung pathology in hamsters treated near peak viral replication due to immune complex and activated complement deposition in pulmonary endothelium, and recruitment of M1 proinflammatory macrophages into the lung parenchyma. However, aside from one report, transient enhanced disease has not been reported in CCP recipient patients, and the transient enhanced disease in Vaxplas hamsters may have been due to mismatched species IgG-FcR interactions, infusion timing, or other experimental factors. Despite transient disease enhancement, Vaxplas dramatically reduced virus replication in lungs and improved infection outcome in SARS-CoV-2-infected hamsters.

Results of phase 2 randomized multi-center study to evaluate the safety and efficacy of infusion of memory T cells as adoptive therapy in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pneumonia and/or lymphopenia (RELEASE NCT04578210)

BACKGROUND AIMS

There are currently no effective anti-viral treatments for coronavirus disease 2019 (COVID-19)-hospitalized patients with hypoxemia. Lymphopenia is a biomarker of disease severity usually present in patients who are hospitalized. Approaches to increasing lymphocytes exerting an anti-viral effect must be considered to treat these patients. Following our phase 1 study, we performed a phase 2 randomized multicenter clinical trial in which we evaluated the efficacy of the infusion of allogeneic off-the-shelf CD45RA- memory T cells containing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific T cells from convalescent donors plus the standard of care (SoC) versus just the SoC treatment.

METHODS

Eighty-four patients were enrolled in three Spanish centers. The patients were randomized into the infusion of 1 × 106/kg CD45RA- memory T cells or the SoC. We selected four unvaccinated donors based on the expression of interferon gamma SARS-CoV-2-specific response within the CD45RA- memory T cells and the most frequent human leukocyte antigen typing in the Spanish population.

RESULTS

We analyzed data from 81 patients. The primary outcome for recovery, defined as the proportion of participants in each group with normalization of fever, oxygen saturation sustained for at least 24 hours and lymphopenia recovery through day 14 or at discharge, was met for the experimental arm. We also observed faster lymphocyte recovery in the experimental group. We did not observe any treatment-related adverse events.

CONCLUSIONS

Adoptive cell therapy with off-the-shelf CD45RA- memory T cells containing SAR-CoV-2-specific T cells is safe, effective and accelerates lymphocyte recovery of patients with COVID-19 pneumonia and/or lymphopenia.

TRIAL REGISTRATION

NCT04578210.

Factors related to the development of high antibody titres against SARS-CoV-2 in convalescent plasma donors from the ConPlas-19 trial

BACKGROUND AND OBJECTIVES

The efficacy of COVID-19 convalescent plasma (CP) associates with high titres of antibodies. ConPlas-19 clinical trial showed that CP reduces the risk of progression to severe COVID-19 at 28 days. Here, we aim to study ConPlas-19 donors and characteristics that associate with high anti-SARS-CoV-2 antibody levels.

MATERIALS AND METHODS

Four-hundred donors were enrolled in ConPlas-19. The presence and titres of anti-SARS-CoV-2 antibodies were evaluated by EUROIMMUN anti-SARS-CoV-2 S1 IgG ELISA.

RESULTS

A majority of 80.3% of ConPlas-19 donor candidates had positive EUROIMMUN test results (ratio ≥1.1), and of these, 51.4% had high antibody titres (ratio ≥3.5). Antibody levels decline over time, but nevertheless, out of 37 donors tested for an intended second CP donation, over 90% were still EUROIMMUN positive, and nearly 75% of those with high titres maintained high titres in the second sample. Donors with a greater probability of developing high titres of anti-SARS-CoV-2 antibodies include those older than 40 years of age (RR 2.06; 95% CI 1.24-3.42), with more than 7 days of COVID-19 symptoms (RR 1.89; 95% CI 1.05-3.43) and collected within 4 months from infection (RR 2.61; 95% CI 1.16-5.90). Male donors had a trend towards higher titres compared with women (RR 1.67; 95% CI 0.91-3.06).

CONCLUSION

SARS-CoV-2 CP candidate donors' age, duration of COVID-19 symptoms and time from infection to donation associate with the collection of CP with high antibody levels. Beyond COVID-19, these data are relevant to inform decisions to optimize the CP donor selection process in potential future outbreaks.

The Role of Convalescent Plasma in COVID-19: A Conclusive Post-Pandemic Review

COVID-19 convalescent plasma (CCP) has represented the frontline response to the COVID-19 pandemic, largely because of encouraging historical evidences in previous pandemics, biological plausibility, and the initial unavailability of targeted antivirals. Unfortunately, investigator-initiated randomized clinical trials in 2020, launched during a stressful pandemic peak, were designed mostly at addressing the main unmet need, i.e., treating critically ill hospitalized patients who were unlikely to benefit from any antiviral therapy. The failure of most of these drugs, in combination with the lack of any sponsor, led to the false belief that convalescent plasma was useless. With the relaxing pandemic stages, evidences have instead mounted that, when administered properly (i.e., within 5 days from onset of symptoms and at high titers of neutralizing antibodies), CCP is as effective as other antivirals at preventing disease progression in outpatients, and also reduces mortality in hospitalized patients. Recently, the focus of clinical use has been on immunosuppressed patients with persistent seronegativity and infection, where a randomized clinical trial has shown a reduction in mortality. Lessons learnt during the COVID-19 pandemic will be of utmost importance for future pandemics.

Staging classification of omicron variant SARS-CoV-2 infection based on dual-spectrometer LIBS (DS-LIBS) combined with machine learning

Effective differentiation of the infection stages of omicron can provide significant assistance in transmission control and treatment strategies. The combination of LIBS serum detection and machine learning methods, as a novel disease auxiliary diagnostic approach, has a high potential for rapid and accurate staging classification of Omicron infection. However, conventional single-spectrometer LIBS serum detection methods focus on detecting the spectra of major elements, while trace elements are more closely related to the progression of COVID-19. Here, we proposed a rapid analytical method with dual-spectrometer LIBS (DS-LIBS) assisted with machine learning to classify different infection stages of omicron. The DS-LIBS, including a broadband spectrometer and a narrowband spectrometer, enables synchronous collection of major and trace elemental spectra in serum, respectively. By employing the RF machine learning models, the classification accuracy using the spectra data collected from DS-LIBS can reach 0.92, compared to 0.84 and 0.73 when using spectra data collected from single-spectrometer LIBS. This significant improvement in classification accuracy highlights the efficacy of the DS-LIBS approach. Then, the performance of four different models, SVM, RF, IGBT, and ETree, is compared. ETree demonstrates the best, with cross-validation and test set accuracies of 0.94 and 0.93, respectively. Additionally, it achieves classification accuracies of 1.00, 0.92, 0.92, and 0.89 for the four stages B1-acute, B1-post, B2, and B3. Overall, the results demonstrate that DS-LIBS combined with the ETree machine learning model enables effective staging classification of omicron infection.

Passive antibody therapy in emerging infectious diseases

The epidemic of corona virus disease 2019 (COVID-19) caused by severe acute respiratory syndrome Coronavirus 2 and its variants of concern (VOCs) has been ongoing for over 3 years. Antibody therapies encompassing convalescent plasma, hyperimmunoglobulin, and neutralizing monoclonal antibodies (mAbs) applied in passive immunotherapy have yielded positive outcomes and played a crucial role in the early COVID-19 treatment. In this review, the development path, action mechanism, clinical research results, challenges, and safety profile associated with the use of COVID-19 convalescent plasma, hyperimmunoglobulin, and mAbs were summarized. In addition, the prospects of applying antibody therapy against VOCs was assessed, offering insights into the coping strategies for facing new infectious disease outbreaks.

Efficacy and Safety of Treatment with Plasma from COVID-19-Recovered Individuals

Convalescent plasma therapy, which involves administering plasma from recovered coronavirus disease 2019 (COVID-19) patients to infected individuals, is being explored as a potential treatment for severe cases of COVID-19. This study aims to evaluate the efficacy and safety of convalescent plasma therapy in COVID-19 patients with moderate to severe illness. An open-label, single-arm intervention study was conducted without a control group. Plasma collected from recovered COVID-19 patients was administered to eligible participants. The primary endpoint was the proportion of patients who were placed on artificial ventilation or died within 14 days of transfusion. Secondary endpoints included clinical improvement, viral load measurements, and adverse event monitoring. A total of 59 cases were included in the study. The primary endpoint was evaluated by comparing the rate obtained in the study to an existing rate of 25%. The study also assessed clinical improvement, viral load changes, and safety endpoints through adverse event monitoring. Convalescent plasma therapy shows potential as a treatment option for COVID-19. This study aimed to provide evidence for the efficacy and safety of this therapy and may contribute to its future use in treating severe cases of COVID-19.

Factors associated with mortality among hospitalized patients with COVID-19 disease treated with convalescent plasma

The use of convalescent plasma (CP) for hospitalized patients with SARS-CoV-2 infection might be a useful option in certain settings. Soon after the outbreak of COVID-19, the National Ministry of Health of Argentina recommended the use of CP transfusion for hospitalized patients with COVID-19 disease. Between 1 June and 3 October 2020, 480 patients, excluding those on invasive mechanical ventilation (IMV), received at least one CP infusion in the province of Santa Fe. We aimed to find factors associated with mortality among this cohort of patients. The median age was 60 years (interquartile range: 49-69 years) and 320 (66.7%) were males. Most of these patients (93.75%) received a single CP infusion, 82.1% and 95.6% before day 4 and day 7 of hospitalization, respectively. Anti-SARS-CoV-2 titers were determined in the CP units administered using Elecsys Anti-SARS-CoV-2 S assay. At 28 days of follow-up, 250 patients were discharged (52.1%), 131 (27.3%) remained hospitalized without and 16 (3.3%) with oxygen requirement, 27 (5.6%) were on IMV, and 56 (11.7%) had died. In the multivariate logistic regression analysis, the factors significantly associated with 28-day mortality were (i) requirement of IMV, (ii) the administration of CP after the third day of hospitalization, (iii) age, and (iv) number of comorbidities. The qualitative and quantitative analyses of antibodies against SARS-CoV-2 in the infused CP were not associated with mortality. Our findings may imply a seemingly favorable effect of CP administration among patients with severe COVID-19 disease when infused sooner after hospitalization.IMPORTANCEThe use of convalescent plasma (CP) could be an option for patients with severe COVID-19, especially in poor-resource countries where direct antiviral drugs are not commercially available. Currently, the U.S. Food and Drug Administration limits the CP administration for outpatients and inpatients with COVID-19 who are immunocompromised and only if high levels of anti-SARS-CoV-2 antibodies are confirmed in the CP unit. Although most of the randomized clinical trials failed to show a clear-cut benefit of CP in hospitalized patients with severe COVID-19, other studies have shown that if given early in the course of the disease, it might be a useful therapeutic option. In this retrospective study, we demonstrated that early treatment (within 3 days of hospitalization) was significantly associated with reduced 28-day mortality compared with those patients treated beyond day 3. The results from our study add up to the scientific evidence on the use of CP as a relatively safe, cheap, and possibly effective therapy in certain patients suffering from severe SARS-CoV-2 infection.

Convalescent Plasma for Covid-19-Induced ARDS in Mechanically Ventilated Patients

BACKGROUND

Passive immunization with plasma collected from convalescent patients has been regularly used to treat coronavirus disease 2019 (Covid-19). Minimal data are available regarding the use of convalescent plasma in patients with Covid-19-induced acute respiratory distress syndrome (ARDS).

METHODS

In this open-label trial, we randomly assigned adult patients with Covid-19-induced ARDS who had been receiving invasive mechanical ventilation for less than 5 days in a 1:1 ratio to receive either convalescent plasma with a neutralizing antibody titer of at least 1:320 or standard care alone. Randomization was stratified according to the time from tracheal intubation to inclusion. The primary outcome was death by day 28.

RESULTS

A total of 475 patients underwent randomization from September 2020 through March 2022. Overall, 237 patients were assigned to receive convalescent plasma and 238 to receive standard care. Owing to a shortage of convalescent plasma, a neutralizing antibody titer of 1:160 was administered to 17.7% of the patients in the convalescent-plasma group. Glucocorticoids were administered to 466 patients (98.1%). At day 28, mortality was 35.4% in the convalescent-plasma group and 45.0% in the standard-care group (P = 0.03). In a prespecified analysis, this effect was observed mainly in patients who underwent randomization 48 hours or less after the initiation of invasive mechanical ventilation. Serious adverse events did not differ substantially between the two groups.

CONCLUSIONS

The administration of plasma collected from convalescent donors with a neutralizing antibody titer of at least 1:160 to patients with Covid-19-induced ARDS within 5 days after the initiation of invasive mechanical ventilation significantly reduced mortality at day 28. This effect was mainly observed in patients who underwent randomization 48 hours or less after ventilation initiation. (Funded by the Belgian Health Care Knowledge Center; ClinicalTrials.gov number, NCT04558476.).

A Randomized Controlled Study Assessing Convalescent Immunoglobulins vs Convalescent Plasma for Hospitalized Patients With Coronavirus 2019

BACKGROUND

It is unknown whether convalescent immunoglobulins (cIgGs) are better than convalescent plasma (CP) for patients with coronavirus 2019 (COVID-19).

METHODS

In this randomized controlled trial, we assigned high risk COVID-19 patients with ≤10 days of symptoms, to receive cIgGs or CP. The primary endpoint was improvement on day 14 according to the World Health Organization scale. Secondary endpoints were survival on day 14, and improvement, survival, and percent of ventilated patients on day 28, and treatment response in unvaccinated and vaccinated patients.

RESULTS

A total of 319 patients were included: 166 received cIgGs and 153 CP. Median age was 64 to 66 years. A total of 112 patients (67.5%) in the cIgG group and 103 patients (67.3%) in the CP group reached the primary endpoint. Difference between groups was 0.1 (95% confidence interval, -10.1 to 10.4; P = .026), failing to reach noninferiority. More patients receiving cIgG improved by day 28 (136 patients [81.9%] and 108 patients [70.6%], respectively; 95% confidence interval, 1.9-20.7; P < .001; for superiority P = .018). Seventeen patients in the cIgG group (10.2%) and 25 patients (16.3%) in the CP group required mechanical ventilation (P = .136). Sixteen (9.6%) and 23 (15%) patients, respectively, died (P = .172). More unvaccinated patients improved by day 28 in the cIgG group (84.1% vs 66.1%; P = .024), and survival was better in the cIgG group (89.9% vs 77.4%; P = .066).

CONCLUSIONS

cIgGs failed to reach the primary noninferiority endpoint on day 14 but was superior to CP on day 28. Survival and improvement by day 28 in unvaccinated patients treated with cIgGs were better. In the face of new variants, cIgGs are a viable option for treating COVID-19.

TRIAL REGISTRATION NUMBER

My Trials MOH_2021-01-14_009667.

Interaction of SARS-CoV-2 with host cells and antibodies: experiment and simulation

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the devastating global COVID-19 pandemic announced by WHO in March 2020. Through unprecedented scientific effort, several vaccines, drugs and antibodies have been developed, saving millions of lives, but the fight against COVID-19 continues as immune escape variants of concern such as Delta and Omicron emerge. To develop more effective treatments and to elucidate the side effects caused by vaccines and therapeutic agents, a deeper understanding of the molecular interactions of SARS-CoV-2 with them and human cells is required. With special interest in computational approaches, we will focus on the structure of SARS-CoV-2 and the interaction of its spike protein with human angiotensin-converting enzyme-2 (ACE2) as a prime entry point of the virus into host cells. In addition, other possible viral receptors will be considered. The fusion of viral and human membranes and the interaction of the spike protein with antibodies and nanobodies will be discussed, as well as the effect of SARS-CoV-2 on protein synthesis in host cells.

Serum anti-Spike immunoglobulin G levels in random blood donors in Italy: High-titre convalescent plasma is easier than ever to procure

BACKGROUND AND OBJECTIVES

COVID-19 convalescent plasma (CCP) has retained potency and clinical efficacy against SARS-CoV-2 and is currently of utmost value for seronegative immunocompromised patients. Since most of the effect is due to the vaccine boost of infection-elicited antibodies, there is a theoretical concern that the frequency of suitable donors is declining.

MATERIALS AND METHODS

In this single-institution serosurvey, we screened 599 consecutive donors attending our area in two different seasons (300 in November 2022 and 299 in February 2023) using the Abbott Alinity® anti-Spike immunoglobulin G assay.

RESULTS

More than 80% of random donors qualify according to the FDA criteria for high-titre CCP (>4350 AU/mL), with a stable trend.

CONCLUSION

Despite reduced anti-Spike vaccine boost deployment in the general population, we have shown here that high-titre CCP units are easier than ever to procure. This finding also has implications for the derivation of standard immunoglobulins, which are finally approaching the potency of hyperimmune serum and could soon represent an alternative to CCP.

Administration of vaccine-boosted COVID-19 convalescent plasma to SARS-CoV-2 infected hamsters decreases virus replication in lungs and hastens resolution of the infection despite transiently enhancing disease and lung pathology

The utility of COVID-19 convalescent plasma (CCP) for treatment of immunocompromised patients who are not able to mount a protective antibody response against SARS-CoV-2 and who have contraindications or adverse effects from currently available antivirals remains unclear. To better understand the mechanism of protection in CCP, we studied viral replication and disease progression in SARS-CoV-2 infected hamsters treated with CCP plasma obtained from recovered COVID patients that had also been vaccinated with an mRNA vaccine, hereafter referred to as Vaxplas. We found that Vaxplas dramatically reduced virus replication in the lungs and improved infection outcome in SARS-CoV-2 infected hamsters. However, we also found that Vaxplas transiently enhanced disease severity and lung pathology in treated animals likely due to the deposition of immune complexes, activation of complement and recruitment of increased numbers of macrophages with an M1 proinflammatory phenotype into the lung parenchyma.

Exercise and Experiments of Nature

In this article, we highlight the contributions of passive experiments that address important exercise-related questions in integrative physiology and medicine. Passive experiments differ from active experiments in that passive experiments involve limited or no active intervention to generate observations and test hypotheses. Experiments of nature and natural experiments are two types of passive experiments. Experiments of nature include research participants with rare genetic or acquired conditions that facilitate exploration of specific physiological mechanisms. In this way, experiments of nature are parallel to classical "knockout" animal models among human research participants. Natural experiments are gleaned from data sets that allow population-based questions to be addressed. An advantage of both types of passive experiments is that more extreme and/or prolonged exposures to physiological and behavioral stimuli are possible in humans. In this article, we discuss a number of key passive experiments that have generated foundational medical knowledge or mechanistic physiological insights related to exercise. Both natural experiments and experiments of nature will be essential to generate and test hypotheses about the limits of human adaptability to stressors like exercise. © 2023 American Physiological Society. Compr Physiol 13:4879-4907, 2023.

Predictors of high SARS-CoV-2 immunoglobulin G titers in COVID-19 convalescent whole-blood donors: a cross-sectional study in China

Background

Demographic information has been shown to help predict high antibody titers of COVID-19 convalescent plasma (CCP) in CCP donors. However, there is no research on the Chinese population and little evidence on whole-blood donors. Therefore, we aimed to investigate these associations among Chinese blood donors after SARS-CoV-2 infection.

Methods

In this cross-sectional study, 5,064 qualified blood donors with confirmed or suspected SARS-CoV-2 infection completed a self-reported questionnaire and underwent tests of SARS-CoV-2 Immunoglobulin G (IgG) antibody and ABO blood type. Logistic regression models were used to calculate odds ratios (ORs) for high SARS-CoV-2 IgG titers according to each factor.

Results

Totally, 1,799 participants (with SARS-CoV-2 IgG titers≥1:160) had high-titer CCPs. Multivariable analysis showed that a 10-year increment in age and earlier donation were associated with higher odds of high-titer CCP, while medical personnel was associated with lower odds. The ORs (95% CIs) of high-titer CCP were 1.17 (1.10-1.23, p< 0.001) and 1.41 (1.25-1.58, p< 0.001) for each 10-year increment in age and earlier donation, respectively. The OR of high-titer CCP was 0.75 (0.60-0.95, p = 0.02) for medical personnel. Female early donors were associated with increased odds of high-titer CCP, but this association was insignificant for later donors. Donating after 8 weeks from the onset was associated with decreased odds of having high-titer CCP compared to donating within 8 weeks from the onset, and the HR was 0.38 (95% CI: 0.22-0.64, p <0.001). There was no significant association between ABO blood type or race and the odds of high-titer CCP.

Discussion

Older age, earlier donation, female early donors, and non-medical-related occupations are promising predictors of high-titer CCP in Chinese blood donors. Our findings highlight the importance of CCP screening at the early stage of the pandemic.

T-cell immunity to SARS-CoV-2: what if the known best is not the optimal course for the long run? Adapting to evolving targets

Humanity did surprisingly well so far, considering how unprepared it was to respond to the coronavirus disease 2019 (COVID-19) threat. By blending old and ingenious new technology in the context of the accumulated knowledge on other human coronaviruses, several vaccine candidates were produced and tested in clinical trials in record time. Today, five vaccines account for the bulk of the more than 13 billion doses administered worldwide. The ability to elicit biding and neutralizing antibodies most often against the spike protein is a major component of the protection conferred by immunization but alone it is not enough to limit virus transmission. Thus, the surge in numbers of infected individuals by newer variants of concern (VOCs) was not accompanied by a proportional increase in severe disease and death rate. This is likely due to antiviral T-cell responses, whose evasion is more difficult to achieve. The present review helps navigating the very large literature on T cell immunity induced by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and vaccination. We examine the successes and shortcomings of the vaccinal protection in the light of the emergence of VOCs with breakthrough potential. SARS-CoV-2 and human beings will likely coexist for a long while: it will be necessary to update existing vaccines to improve T-cell responses and attain better protection against COVID-19.

Therapeutic strategies for COVID-19: progress and lessons learned

The coronavirus disease 2019 (COVID-19) pandemic has stimulated tremendous efforts to develop therapeutic strategies that target severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and/or human proteins to control viral infection, encompassing hundreds of potential drugs and thousands of patients in clinical trials. So far, a few small-molecule antiviral drugs (nirmatrelvir-ritonavir, remdesivir and molnupiravir) and 11 monoclonal antibodies have been marketed for the treatment of COVID-19, mostly requiring administration within 10 days of symptom onset. In addition, hospitalized patients with severe or critical COVID-19 may benefit from treatment with previously approved immunomodulatory drugs, including glucocorticoids such as dexamethasone, cytokine antagonists such as tocilizumab and Janus kinase inhibitors such as baricitinib. Here, we summarize progress with COVID-19 drug discovery, based on accumulated findings since the pandemic began and a comprehensive list of clinical and preclinical inhibitors with anti-coronavirus activities. We also discuss the lessons learned from COVID-19 and other infectious diseases with regard to drug repurposing strategies, pan-coronavirus drug targets, in vitro assays and animal models, and platform trial design for the development of therapeutics to tackle COVID-19, long COVID and pathogenic coronaviruses in future outbreaks.

Efficacy of Convalescent Plasma to Treat Long-Standing COVID-19 in Patients with B-Cell Depletion

The use of antivirals, corticosteroids, and IL-6 inhibitors has been recommended by the WHO to treat COVID-19. CP has also been considered for severe and critical cases. Clinical trials on CP have shown contradictory results, but an increasing number of patients, including immunocompromised ones, have shown benefits from this treatment. We reported two clinical cases of patients with prolonged COVID-19 infection and B-cell depletion who showed rapid clinical and virological recovery after the administration of CP. The first patient in this study was a 73-year-old female with a history of follicular non-Hodgkin lymphoma previously treated with bendamustine followed by maintenance therapy with rituximab. The second patient was a 68-year-old male with chronic obstructive pulmonary disease, bipolar disorder, alcoholic liver disease, and a history of mantellar non-Hodgkin lymphoma treated with rituximab and radiotherapy. After the administration of CP, both patients showed a resolution of symptoms, improvement of their clinical conditions, and a negative result of the nasopharyngeal swab test. The administration of CP might be effective in resolving symptoms and improving clinical and virological outcomes in patients with B-cell depletion and prolonged SARS-CoV2 infections.

Convalescent plasma therapy in COVID-19: Unravelling the data using the principles of antibody therapy

INTRODUCTION

When the COVID-19 pandemic struck no specific therapies were available and many turned to COVID-19 convalescent plasma (CCP), a form of antibody therapy. The literature provides mixed evidence for CCP efficacy.

AREAS COVERED

PubMed was searched using the words COVID-19 and convalescent plasma and individual study designs were evaluated for adherence to the three principles of antibody therapy, i.e. that plasma 1) contain specific antibody; 2) have enough specific antibody to mediate a biological effect; and 3) be administered early in the course of disease. Using this approach, a diverse and seemingly contradictory collection of clinical findings was distilled into a consistent picture whereby CCP was effective when used according to the above principles of antibody therapy. In addition, CCP therapy in immunocompromised patients is useful at any time in the course of disease.

EXPERT OPINION

CCP is safe and effective when used appropriately. Today, most of humanity has some immunity to SARS-CoV-2 from vaccines and infection, which has lessened the need for CCP in the general population. However, COVID-19 in immunocompromised patients is a major therapeutic challenge, and with the deauthorization of all SARS-CoV-2-spike protein-directed monoclonal antibodies, CCP is the only antibody therapy available for this population.

An update on SARS-CoV-2 immunization and future directions

Millions of people have died as a result of SARS-CoV-2, which was first discovered in China and has since spread globally. Patients with SARS-CoV-2 infection may show a range of symptoms, including fever, coughing, and shortness of breath, or they may show no symptoms at all. To treat COVID-19 symptoms and avoid serious infections, many medications and vaccinations have been employed. However, to entirely eradicate COVID-19 from the world, next-generation vaccine research is required because of the devastating consequences it is having for humanity and every nation's economy. Scientists are working hard to eradicate this dangerous virus across the world. SARS-CoV-2 has also undergone significant mutation, leading to distinct viral types such as the alpha, beta, gamma, delta, and omicron variants. This has sparked discussion about the effectiveness of current vaccines for the newly formed variants. A proper comparison of these vaccinations is required to compare their efficacy as the number of people immunized against SARS-CoV-2 globally increases. Population-level statistics evaluating the capacity of these vaccines to reduce infection are therefore being developed. In this paper, we analyze the many vaccines on the market in terms of their production process, price, dosage needed, and efficacy. This article also discusses the challenges of achieving herd immunity, the likelihood of reinfection, and the importance of convalescent plasma therapy in reducing infection.

Polypharmacology of ambroxol in the treatment of COVID-19

The pandemic of coronavirus disease 2019 (COVID-19) by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is still underway. Due to the growing development of severe symptoms, it is necessary to promote effective therapies. Ambroxol [2-amino-3,5-dibromo-N-(trans-4-hydroxycyclohexyl) benzylamine] has long been used as one of the over-the-counter mucolytic agents to treat various respiratory diseases. Therefore, we focused on the mechanism of action of ambroxol in COVID-19 treatment. In vitro and in silico screening revealed that ambroxol may impede cell entry of SARS-CoV-2 by binding to neuropilin-1. Ambroxol could also interact with multiple inflammatory factors and signaling pathways, especially nuclear factor kappa B (NF-κB), to interfere cytokines cascade activated by SARS-CoV-2 internalization. Furthermore, multipathways and proteins, such as the cell cycle and matrix metalloproteinases (MMPs), were identified as significant ambroxol-targeting pathways or molecules in PBMC and lung of severe COVID-19 patients by bioinformatics analysis. Collectively, these results suggested that ambroxol may serve as a promising therapeutic candidate for the treatment of severe SARS-CoV-2 infection.

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.

Effectiveness of COVID-19 Convalescent Plasma (CCP) During the Pandemic Era: A Literature Review

Worldwide pandemic with coronavirus disease-2019 (COVID-19) was caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). As November 2, 2022, World Health Organization (WHO) received 628,035,553 reported incidents on COVID-19, with 6,572,800 mortalities and, with a total 12,850,970,971 vaccine doses have been delivered as of October 31, 2022. The infection can cause mild or self-limiting symptoms of pulmonary and severe infections or death may be caused by SARS-CoV-2 infection. Simultaneously, antivirals, corticosteroids, immunological treatments, antibiotics, and anticoagulants have been proposed as potential medicines to cure COVID-19 affected patients. Among these initial treatments, COVID-19 convalescent plasma (CCP), which was retrieved from COVID-19 recovered patients to be used as passive immune therapy, in which antibodies from cured patients were given to infected patients to prevent illness. Such treatment has yielded the best results in earlier with preventative or early stages of illness. Convalescent plasma (CP) is the first treatment available when infectious disease initially appears, although few randomized controlled trials (RCTs) were conducted to evaluate its effectiveness. The historical record suggests with potential benefit for other respiratory infections, as coronaviruses like Severe Acute Respiratory Syndrome-CoV-I (SARS-CoV-I) and Middle Eastern Respiratory Syndrome (MERS), though the analysis of such research is constrained by some non-randomized experiments (NREs). Rigorous studies on CP are made more demanding by the following with the immediacy of the epidemics, CP use may restrict the ability to utilize it for clinical testing, non-homogenous nature of product, highly decentralized manufacturing process; constraints with capacity to measure biologic function, ultimate availability of substitute therapies, as antivirals, purified immune globulins, or monoclonal antibodies. Though, it is still not clear how effectively CCP works among hospitalized COVID-19 patients. The current review tries to focus on its efficiency and usage in clinical scenarios and identifying existing benefits of implementation during pandemic or how it may assist with future pandemic preventions.

Pathogen reduction with methylene blue does not have an impact on the clinical effectiveness of COVID-19 convalescent plasma

BACKGROUND AND OBJECTIVES

There is a concern about a possible deleterious effect of pathogen reduction (PR) with methylene blue (MB) on the function of immunoglobulins of COVID-19 convalescent plasma (CCP). We have evaluated whether MB-treated CCP is associated with a poorer clinical response compared to other inactivation systems at the ConPlas-19 clinical trial.

MATERIALS AND METHODS

This was an ad hoc sub-study of the ConPlas-19 clinical trial comparing the proportion of patients transfused with MB-treated CCP who had a worsening of respiration versus those treated with amotosalen (AM) or riboflavin (RB).

RESULTS

One-hundred and seventy-five inpatients with SARS-CoV-2 pneumonia were transfused with a single CCP unit. The inactivation system of the CCP units transfused was MB in 90 patients (51.4%), RB in 60 (34.3%) and AM in 25 (14.3%). Five out of 90 patients (5.6%) transfused with MB-treated CCP had worsening respiration compared to 9 out of 85 patients (10.6%) treated with alternative PR methods (p = 0.220). Of note, MB showed a trend towards a lower rate of respiratory progressions at 28 days (risk ratio, 0.52; 95% confidence interval, 0.18-1.50).

CONCLUSION

Our data suggest that MB-treated CCP does not provide a worse clinical outcome compared to the other PR methods for the treatment of COVID-19.

Omicron, Long-COVID, and the Safety of Elective Surgery for Adults and Children: Joint Guidance from the Therapeutics and Guidelines Committee of the Surgical Infection Society and the Surgery Strategic Clinical Network, Alberta Health Services

Background: Active and recent coronavirus disease 2019 (COVID-19) infections are associated with morbidity and mortality after surgery in adults. Current recommendations suggest delaying elective surgery in survivors for four to 12 weeks, depending on initial illness severity. Recently, the predominant causes of COVID-19 are the highly transmissible/less virulent Omicron variant/subvariants. Moreover, increased survivability of primary infections has engendered the long-COVID syndrome, with protean manifestations that may persist for months. Considering the more than 600,000,000 COVID-19 survivors, surgeons will likely be consulted by recovered patients seeking elective operations. Knowledge gaps of the aftermath of Omicron infections raise questions whether extant guidance for timing of surgery still applies to adults or should apply to the pediatric population. Methods: Scoping review of relevant English-language literature. Results: Most supporting data derive from early in the pandemic when the Alpha variant of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) predominated. The Omicron variant/subvariants generally cause milder infections with less organ dysfunction; many infections are asymptomatic, especially in children. Data are scant with respect to adult surgical outcomes after Omicron infection, and especially so for pediatric surgical outcomes at any stage of the pandemic. Conclusions: Numerous knowledge gaps persist with respect to the disease, the recovered pre-operative patient, the nature of the proposed procedure, and supporting data. For example, should the waiting period for all but urgent elective surgery be extended beyond 12 weeks, e.g., after serious/critical illness, or for patients with long-COVID and organ dysfunction? Conversely, can the waiting periods for asymptomatic patients or vaccinated patients be shortened? How shall children be risk-stratified, considering the distinctiveness of pediatric COVID-19 and the paucity of data? Forthcoming guidelines will hopefully answer these questions but may require ongoing modifications based on additional new data and the epidemiology of emerging strains.

WHO Is Recommending against the Use of COVID-19 Convalescent Plasma in Immunocompromised Patients?

Since December 2019, SARS-CoV-2 is ravaging the globe, currently accounting for over 660 million infected people and more than 6 [...].

COVID-19 Convalescent Plasma for the Treatment of Immunocompromised Patients: A Systematic Review and Meta-analysis

Importance

Patients who are immunocompromised have increased risk for morbidity and mortality associated with coronavirus disease 2019 (COVID-19) because they less frequently mount antibody responses to vaccines. Although neutralizing anti-spike monoclonal-antibody treatment has been widely used to treat COVID-19, evolutions of SARS-CoV-2 have been associated with monoclonal antibody-resistant SARS-CoV-2 variants and greater virulence and transmissibility of SARS-CoV-2. Thus, the therapeutic use of COVID-19 convalescent plasma has increased on the presumption that such plasma contains potentially therapeutic antibodies to SARS-CoV-2 that can be passively transferred to the plasma recipient.

Objective

To assess the growing number of reports of clinical experiences of patients with COVID-19 who are immunocompromised and treated with specific neutralizing antibodies via COVID-19 convalescent plasma transfusion.

Data Sources

On August 12, 2022, a systematic search was performed for clinical studies of COVID-19 convalescent plasma use in patients who are immunocompromised.

Study Selection

Randomized clinical trials, matched cohort studies, and case report or series on COVID-19 convalescent plasma use in patients who are immunocompromised were included. The electronic search yielded 462 unique records, of which 199 were considered for full-text screening.

Data Extraction and Synthesis

The study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Data were extracted by 3 independent reviewers in duplicate and pooled.

Main Outcomes and Meaures

The prespecified end point was all-cause mortality after COVID-19 convalescent plasma transfusion; exploratory subgroup analyses were performed based on putative factors associated with the potential mortality benefit of convalescent plasma.

Results

This systematic review and meta-analysis included 3 randomized clinical trials enrolling 1487 participants and 5 controlled studies. Additionally, 125 case series or reports enrolling 265 participants and 13 uncontrolled large case series enrolling 358 participants were included. Separate meta-analyses, using models both stratified and pooled by study type (ie, randomized clinical trials and matched cohort studies), demonstrated that transfusion of COVID-19 convalescent plasma was associated with a decrease in mortality compared with the control cohort for the amalgam of both randomized clinical trials and matched cohort studies (risk ratio [RR], 0.63 [95% CI, 0.50-0.79]).

Conclusions and Relevance

These findings suggest that transfusion of COVID-19 convalescent plasma is associated with mortality benefit for patients who are immunocompromised and have COVID-19.

The Potential Role of Passive Antibody-Based Therapies as Treatments for Monkeypox

Monkeypox, a zoonosis caused by the orthopox monkeypox virus (MPXV) that is endemic to Central and West Africa, was previously linked to sporadic outbreaks and rare, travel-associated cases. An outbreak of monkeypox in 2022 has spurred a public health emergency of international concern, and this outbreak is unprecedented in terms of its scale and epidemiology. The outbreak has been focused overwhelmingly in men who have sex with men; however, the trajectory of the outbreak remains uncertain, with spread now being reported in women and children. The mortality has been low (<1%), yet the morbidity is high. Vaccines and oral antiviral agents that have been developed to protect against smallpox are available for use against monkeypox. However, the supply has been unable to match the demand during the outbreak. Passive antibody-based therapies, such as hyperimmune globulin (HIG), monoclonal antibodies, and convalescent plasma (CP), have been used against a diverse array of infectious diseases, culminating in their extensive use during the COVID-19 pandemic. Passive antibody-based therapies could play a role in the treatment of monkeypox, either as a temporizing role amid a shortfall in vaccines and antivirals or a complementary role to direct-acting antivirals. Drawing on the collective experience to date, there are regulatory, administrative, and logistical challenges to the implementation of antibody-based therapies. Their efficacy is contingent upon early administration and the presence of high-titer antibodies against the targeted pathogen. Research is needed to address questions pertaining to how to qualify HIG and CP and to determine their relative efficacy against MPXV, compared to antecedent therapies and preventative strategies. IMPORTANCE Monkeypox is an infection caused by the monkeypox virus (MPXV). The clinical findings in monkeypox include fever and rash. Historically, most cases of human monkeypox were reported in Africa. This changed in 2022, with a massive escalation in the number of cases across multiple countries, mainly affecting men who have sex with men. Although vaccines and oral antiviral medications are available for the treatment of monkeypox, their supply has been overwhelmed by the unprecedented number of cases. Antibody-based therapies (ABTs) have long been used to treat infectious diseases. They are produced in a laboratory or from plasma that has been collected from individuals who have recovered from an infection or have been vaccinated against that infection (in this case, monkeypox). ABTs could play a role in the treatment of monkeypox, either while awaiting oral medications or as a complementary treatment for patients that are at risk of severe disease.

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".

The Omicron variant of concern: Diversification and convergent evolution in spike protein, and escape from anti-Spike monoclonal antibodies

WHO-defined SARS-CoV-2 variants of concern (VOC) drive therapeutics and vaccine development. The Omicron VOC is dominating the arena since November 2021, but the number of its sublineages is growing in complexity. Omicron represent a galaxy with a myriad of stars that suddenly rise and expand before collapsing into apparent extinction when a more fit sublineage appears. This has already happened with BA.1, BA.2, and BA.4/5 and is happening with BA.2.75. We review here the current PANGO phylogeny, focusing on sublineages with Spike mutations, and show how frequently xxxxxxxx convergent evolution has occurred in these sublineages. We finally summarize how Omicron evolution has progressively defeated the anti-Spike monoclonal antibodies authorized so far, leaving clinicians to again fall back on COVID19 convalescent plasma from vaccinated donors as the only antibody-based therapy available.

Validation of Viral Inactivation Protocols for Therapeutic Blood Products against Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-COV-2)

Therapeutic blood products including convalescent plasma/serum and immunoglobulins concentrated from convalescent plasma, such as intravenous immunoglobulins or hyperimmune globulins, and monoclonal antibodies are passive immunotherapy options for novel coronavirus disease 2019 (COVID-19). They have been shown to improve the clinical status and biological and radiological parameters in some groups of COVID-19 patients. However, blood products are still potential sources of virus transmission in recipients. The use of pathogen reduction technology (PRT) should increase the safety of the products. The purpose of this study was to determine the impact of solvent/detergents (S/D) procedures on SARS-COV-2 infectivity elimination in the plasma of donors but also on COVID-19 convalescent serum (CCS) capacity to neutralize SARS-COV-2 infectivity. In this investigation, S/D treatment for all experiments was performed at a shortened process time (30 min). We first evaluated the impact of S/D treatments (1% TnBP/1% TritonX-45 and 1% TnBP/1% TritonX-100) on the inactivation of SARS-COV-2 pseudoparticles (SARS-COV-2pp)-spiked human plasma followed by S/D agent removal using a Sep-Pak Plus C18 cartridge. Both treatments were able to completely inactivate SARS-COV-2pp infectivity to an undetectable level. Moreover, the neutralizing activity of CCS against SARS-COV-2pp was preserved after S/D treatments. Our data suggested that viral inactivation methods using such S/D treatments could be useful in the implementation of viral inactivation/elimination processes of therapeutic blood products against SARS-COV-2.

Outcomes of Convalescent Plasma with Defined High versus Lower Neutralizing Antibody Titers against SARS-CoV-2 among Hospitalized Patients: CoronaVirus Inactivating Plasma (CoVIP) Study

COVID-19 convalescent plasma (CCP) was an early and widely adopted putative therapy for severe COVID-19. Results from randomized control trials and observational studies have failed to demonstrate a clear therapeutic role for CCP for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Underlying these inconclusive findings is a broad heterogeneity in the concentrations of neutralizing antibodies (nAbs) between different CCP donors. We conducted this study to evaluate the effectiveness and safety of nAb titer-defined CCP in adults admitted to an academic referral hospital. Patients positive by a SARS-CoV-2 nucleic acid amplification test and with symptoms for <10 days were eligible. Participants received either CCP with nAb titers of >1:640 (high-titer group) or ≥1:160 to 1:640 (standard-titer group) in addition to standard of care treatments. The primary clinical outcome was time to hospital discharge, with mortality and respiratory support evaluated as secondary outcomes. Adverse events were contrasted by CCP titer. Between 28 August and 4 December 2020, 316 participants were screened, and 55 received CCP, with 14 and 41 receiving high- versus standard-titer CCP, respectively. Time to hospital discharge was shorter among participants receiving high- versus standard-titer CCP, accounting for death as a competing event (hazard ratio, 1.94; 95% confidence interval [CI], 1.05 to 3.58; Gray's P = 0.02). Severe adverse events (SAEs) (≥grade 3) occurred in 4 (29%) and 23 (56%) of participants receiving the high versus standard titer, respectively, by day 28 (risk ratio, 0.51; 95% CI, 0.21 to 1.22; Fisher's P = 0.12). There were no observed treatment-related AEs. (This study has been registered at ClinicalTrials.gov under registration no. NCT04524507). IMPORTANCE In this study, in a high-risk population of patients admitted for COVID-19, we found an earlier time to hospital discharge among participants receiving CCP with nAb titers of >1:640 compared with participants receiving CCP with a lower nAb titer and no CCP-related AEs. The significance of our research is in identifying a dose response of CCP and clinical outcomes based on nAb titer. Although limited by a small study size, these findings support further study of high-nAb-titer CCP defined as >1:640 in the treatment of COVID-19.

Home and Out-of-Hospital Therapy with COVID-19 Convalescent Plasma in Europe

COVID19 convalescent plasma (CCP) has proven an effective treatment for outpatients, and CCP collected from vaccinated donors is among the few effective therapeutic options for immunocompromised patients. Despite this, most countries are still relying over in-hospital compassionate usages outside clinical trials. Given the need for early treatment, home transfusions are expecially needed. We review here the state of the art for out-of-hospital CCP transfusions and discuss solutions to potential burocratic hurdles.