Targeting coagulation activation in severe COVID-19 pneumonia: lessons from bacterial pneumonia and sepsis

Plasma tissue factor pathway inhibitor levels in coronavirus disease 2019 patients: a systematic review and meta-analysis

Studies have suggested a relationship between tissue factor pathway inhibitor (TFPI) and coronavirus disease 2019 (COVID-19) severity. However, there is inconsistency in the findings of the studies. To enhance comprehension of this relationship, a meta-analysis was conducted. PubMed, Web of Science, and Scopus databases were searched to identify eligible studies. The mean difference was employed as effect measures and the standardized mean difference (SMD) and the 95% confidence interval (CI) were utilized as a summary statistic. Heterogeneity was assessed through the application of the chi-square test and the I2 statistic. The included studies' quality and risk of bias were assessed using the Newcastle-Ottawa assessment scale, adapted for case-control studies. A total of six studies were included with 684 cases and healthy controls (180 healthy controls and 504 COVID-19 patients with different severity, 76 mild, 292 moderate, and 136 severe). The analysis revealed a significant increase in the TFPI level in COVID-19 patients with moderate severity compared with healthy controls (SMD = 0.95 ng/ml, 95% confidence interval (CI) 0.27, 1.63 ng/ml; I2 : 87.2%). The increased TFPI level in mild and moderate COVID-19 was not significant, SMD = 0.68 ng/ml, 95% CI -0.64 to 2.0 ng/ml; I2 92.9% and SMD = 0.62 ng/ml, 95% CI -0.62 to 1.86 ng/ml; I2 91.5%, respectively. In addition, most studies indicate an association of the increased TFPI concentrations with increased markers of inflammation, endothelial damage, and hypercoagulation. Considering the anticoagulant and anti-inflammatory roles of TFPI, its increase seems to be aimed at modulating COVID-19-induced hyper-inflammation and hyper-coagulation state.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42023437353.

A Comparison between SARS-CoV-2 and Gram-Negative Bacteria-Induced Hyperinflammation and Sepsis

Sepsis is a life-threatening condition caused by the body's overwhelming response to an infection, such as pneumonia or urinary tract infection. It occurs when the immune system releases cytokines into the bloodstream, triggering widespread inflammation. If not treated, it can lead to organ failure and death. Unfortunately, sepsis has a high mortality rate, with studies reporting rates ranging from 20% to over 50%, depending on the severity and promptness of treatment. According to the World Health Organization (WHO), the annual death toll in the world is about 11 million. One of the main toxins responsible for inflammation induction are lipopolysaccharides (LPS, endotoxin) from Gram-negative bacteria, which rank among the most potent immunostimulants found in nature. Antibiotics are consistently prescribed as a part of anti-sepsis-therapy. However, antibiotic therapy (i) is increasingly ineffective due to resistance development and (ii) most antibiotics are unable to bind and neutralize LPS, a prerequisite to inhibit the interaction of endotoxin with its cellular receptor complex, namely Toll-like receptor 4 (TLR4)/MD-2, responsible for the intracellular cascade leading to pro-inflammatory cytokine secretion. The pandemic virus SARS-CoV-2 has infected hundreds of millions of humans worldwide since its emergence in 2019. The COVID-19 (Coronavirus disease-19) caused by this virus is associated with high lethality, particularly for elderly and immunocompromised people. As of August 2023, nearly 7 million deaths were reported worldwide due to this disease. According to some reported studies, upregulation of TLR4 and the subsequent inflammatory signaling detected in COVID-19 patients "mimics bacterial sepsis". Furthermore, the immune response to SARS-CoV-2 was described by others as "mirror image of sepsis". Similarly, the cytokine profile in sera from severe COVID-19 patients was very similar to those suffering from the acute respiratory distress syndrome (ARDS) and sepsis. Finally, the severe COVID-19 infection is frequently accompanied by bacterial co-infections, as well as by the presence of significant LPS concentrations. In the present review, we will analyze similarities and differences between COVID-19 and sepsis at the pathophysiological, epidemiological, and molecular levels.

Xuebijing injection, a Chinese patent medicine, against severe pneumonia: Current research progress and future perspectives

Severe pneumonia is one of the most common infectious diseases and the leading cause of sepsis and septic shock. Preventing infection, balancing the patient's immune status, and anti-coagulation therapy are all important elements in the treatment of severe pneumonia. As multi-target agents, Xuebijing injection (XBJ) has shown unique advantages in targeting complex conditions and saving the lives of patients with severe pneumonia. This review outlines progress in the understanding of XBJ's anti-inflammatory, endotoxin antagonism, and anticoagulation effects. From the hundreds of publications released over the past few years, the key results from representative clinical studies of XBJ in the treatment of severe pneumonia were selected and summarized. XBJ was observed to effectively suppress the release of pro-inflammatory cytokines, counter the effects of endotoxin, and assert an anticoagulation effect in most clinical trials, which are consistent with experimental studies. Collectively, this evidence suggests that XBJ could play an important and expanding role in clinical medicine, especially for sepsis, septic shock and severe pneumonia. Please cite this article as: Zhang M, Zheng R, Liu WJ, Hou JL, Yang YL, Shang HC. Xuebijing injection, a Chinese patent medicine, against severe pneumonia: Current research progress and future perspectives. J Integr Med. 2023; 21(5): 413-422.

New insights for infection mechanism and potential targets of COVID-19: Three Chinese patent medicines and three Chinese medicine formulas as promising therapeutic approaches

The coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with high pathogenicity and infectiousness has become a sudden and lethal pandemic worldwide. Currently, there is no accepted specific drug for COVID-19 treatment. Therefore, it is extremely urgent to clarify the pathogenic mechanism and develop effective therapies for patients with COVID-19. According to several reliable reports from China, traditional Chinese medicine (TCM), especially for three Chinese patent medicines and three Chinese medicine formulas, has been demonstrated to effectively alleviate the symptoms of COVID-19 either used alone or in combination with Western medicines. In this review, we systematically summarized and analyzed the pathogenesis of COVID-19, the detailed clinical practice, active ingredients investigation, network pharmacology prediction and underlying mechanism verification of three Chinese patent medicines and three Chinese medicine formulas in the COVID-19 combat. Additionally, we summarized some promising and high-frequency drugs of these prescriptions and discussed their regulatory mechanism, which provides guidance for the development of new drugs against COVID-19. Collectively, by addressing critical challenges, for example, unclear targets and complicated active ingredients of these medicines and formulas, we believe that TCM will represent promising and efficient strategies for curing COVID-19 and related pandemics.

Strategies Tackling Viral Replication and Inflammatory Pathways as Early Pharmacological Treatment for SARS-CoV-2 Infection: Any Potential Role for Ketoprofen Lysine Salt?

COVID-19 is an infective disease resulting in widespread respiratory and non-respiratory symptoms prompted by SARS-CoV-2 infection. Interaction between SARS-CoV-2 and host cell receptors prompts activation of pro-inflammatory pathways which are involved in epithelial and endothelial damage mechanisms even after viral clearance. Since inflammation has been recognized as a critical step in COVID-19, anti-inflammatory therapies, including both steroids and non-steroids as well as cytokine inhibitors, have been proposed. Early treatment of COVID-19 has the potential to affect the clinical course of the disease regardless of underlying comorbid conditions. Non-steroidal anti-inflammatory drugs (NSAIDs), which are widely used for symptomatic relief of upper airway infections, became the mainstay of early phase treatment of COVID-19. In this review, we discuss the current evidence for using NSAIDs in early phases of SARS-CoV-2 infection with focus on ketoprofen lysine salt based on its pharmacodynamic and pharmacokinetic features.

Early but reversible haemostatic changes in a-symptomatic females expressing COVID-19 antibodies

The coronavirus, COVID-19 pandemic spread across the globe in 2020, with an initial high case mortality in those requiring intensive care treatment due to serious complication. A vaccine programme was quickly developed and currently the UK is one of highest double vaccinated and boosted countries in the world. Despite tremendous efforts by the UK, new cases of COVID-19 are still occurring, due to viral mutation. A major problem associated with COVID-19 is the large a-symptomatic spread within the population. Little investigation into the a-symptomatic population has been carried out and therefore we pose that the residual effects of a-symptomatic infection is still largely unknown. Prior to mass vaccination, a multi-phased single cohort study of IgM and IgG COVID-19 antibody prevalence and the associated haemostatic changes were assessed in a Welsh cohort of 739 participants, at three time points. Positive antibody participants with age and gender matched negative antibody controls were assessed at 0, 3 and 6 months. Antibody positive females appeared to have lower antibody responses in comparison to their a-symptomatic male counterparts. Despite this initial testing showed a unique significant increase in TRAP-6-induced platelet aggregation, prothrombin time (PT) and clot initiation time. Despite coagulation parameters beginning to return to normal at 3 months, significant decreases are observed in both haemoglobin and haematocrit levels. The production of extracellular vesicles (EV) was also determined in this study. Although the overall number of EV does not change throughout the study, at the initial 0 months' time point a significant increase in the percentage of circulating pro-coagulant platelet derived EV is seen, which does not appear to be related to the extent of platelet activation in the subject. We conclude that early, but reversible changes in haemostatic pathways within the a-symptomatic, female, antibody positive COVID-19 individuals are present. These changes may be key in identifying a period of pro-coagulative risk for a-symptomatic female patients.

Vitamins C and D and COVID-19 Susceptibility, Severity and Progression: An Evidence Based Systematic Review

Background and Objectives: Starting in early December 2019, the novel Coronavirus Disease (COVID-19) from infection with COVID-19 has caused a global pandemic. Many aspects of its pathogenesis and related clinical consequences are still unclear. Early diagnosis and dynamic monitoring of prognostic factors are essential to improve the ability to manage COVID-19 infection. This study aimed to provide an account of the role played by vitamins C and D on the onset, progression and severity of COVID-19. Clinical features and infection-related risk factors are also briefly discussed. Material and Methods: In March 2022, the main online databases were accessed. All the articles that investigate the possible role of vitamins C and D on COVID-19 susceptibility, severity and progression were considered. Results: The current evidence on vitamin C and D supplementation in patients with COVID-19 infection is inconsistent and controversial. In some studies, vitamins were used as coadjuvant of a formal experimental therapy, while in others as main treatment. Ethnicity and hospital setting (inpatient/outpatient) were also variable. Moreover, there was no consensus between studies in administration protocol: high heterogeneity in dosage, administration, and duration of the treatment were evident. Finally, some studies administered vitamins pre- and/or during COVID infection, in patients with different risk factors and infection severity. Conclusions: While waiting to develop a targeted, safe and effective therapy, it is important to investigate individual predisposition and proper disease management. Concluding, available data on the use of nutraceuticals in COVID-19 are inconsistent. However, there is a lack of evidence-based guidelines which recommend vitamin C and D supplementation in patients with COVID-19, and results from high quality randomised controlled trials (RCTs) are inconsistent. Current investigations so far are mostly observational, and include a relatively small sample size which can lead to biased results. Large-scale multicentre studies are therefore needed.

Vitamin C and its therapeutic potential in the management of COVID19

COVID19 has emerged as one of the worst pandemics in the history of mankind. Several vaccines have been approved by different government agencies worldwide, but data on their efficacy and safety are limited, and distribution remains a massive challenge. As per WHO, personal immunity is vital for protection against COVID19. Earlier, Vitamin C-mediated pathways have been shown to play critical role in boosting immunity attributed to its antioxidant properties. Recently, the involvement of such pathways in protection against COVID19 has been suggested. The controlled doses of Vitamin C administered through intravenous (IV) injections are being studied for determining its role in the prognosis of COVID19. In this article, we have discussed the potential role of Vitamin C in the management in COVID19 patients and presented recent clinical trials data. Additionally, we have elaborated the possibility of administering Vitamin C through inhalers in order to achieve local high concentration and the challenges of such approach.

Anticoagulant Treatment in Severe ARDS COVID-19 Patients

Patients with COVID-19 may complicate their evolution with thromboembolic events. Incidence of thromboembolic complications are high and also, patients with the critically-ill disease showed evidence of microthrombi and microangiopathy in the lung probably due to endothelial damage by directly and indirectly injured endothelial and epithelial cells. Pulmonary embolism, deep venous thrombosis and arterial embolism were reported in patients with COVID-19, and several analytical abnormal coagulation parameters have been described as well. D-dimer, longer coagulation times and lower platelet counts have been associated with poor outcomes. The use of anticoagulation or high doses of prophylactic heparin is controversial. Despite the use of anticoagulation or high prophylactic dose of heparin have been associated with better outcomes in observational studies, only in patients with non-critically ill disease benefits for anticoagulation was observed. In critically-ill patient, anticoagulation was not associated with better outcomes. Other measures such as antiplatelet therapy, fibrinolytic therapy or nebulized anticoagulants are being studied in ongoing clinical trials.

Exploring the pathways of inflammation and coagulopathy in COVID-19: A narrative tour into a viral rabbit hole

Worldwide COVID-19 pandemic has taken a huge toll of morbidity and mortality. In selected patients, classified as severe, the overwhelming inflammatory state imposed by this infection is accompanied by a hypercoagulable state, hallmarked by a unique pattern; a marked increase in D-dimer, out of proportion to other markers of coagulopathy. In this review, we turn a spotlight to this phenomenon, offering a unified conceptual model depicting the leading hypotheses of coagulopathy in COVID-19. The key players of the coagulation cascades accompanying the COVID-19 inflammation malfunction on virtually every level; tissue factor expression is amplified, physiological anti-coagulant pathways (anti-thrombin, protein C and S, and the inhibitor of the tissue factor pathway) are impaired and fibrinolysis is inhibited. Components of autoimmunity, the complement system amongst others, further contribute to the pathology. As data continue to gather, our model offers a pathophysiological overview of COVID-19 coagulopathy, defined by the resultant histopathology: either intra-vascular or extra-vascular. We hope this review will facilitate understanding and serve as a lead point to future therapeutic directives.

The Role of High-Density Lipoprotein in COVID-19

The current Coronavirus disease 2019 (COVID-19) pandemic has become a global challenge. Managing a large number of acutely ill patients in a short time, whilst reducing the fatality rate and dealing with complications, brings unique difficulties. The most striking pathophysiological features of patients with severe COVID-19 are dysregulated immune responses and abnormal coagulation function, which can result in multiple-organ failure and death. Normally metabolized high-density lipoprotein (HDL) performs several functions, including reverse cholesterol transport, direct binding to lipopolysaccharide (LPS) to neutralize LPS activity, regulation of inflammatory response, anti-thrombotic effects, antioxidant, and anti-apoptotic properties. Clinical data shows that significantly decreased HDL levels in patients with COVID-19 are correlated with both disease severity and mortality. However, the role of HDL in COVID-19 and its specific mechanism remain unclear. In this analysis, we review current evidence mainly in the following areas: firstly, the pathophysiological characteristics of COVID-19, secondly, the pleiotropic properties of HDL, thirdly, the changes and clinical significance of HDL in COVID-19, and fourthly the prospect of HDL-targeting therapy in COVID-19 to clarify the role of HDL in the pathogenesis of COVID-19 and discuss the potential of HDL therapy in COVID-19.

Dietary Supplements and Nutraceuticals under Investigation for COVID-19 Prevention and Treatment

Coronavirus disease 2019 (COVID-19) has caused global disruption and a significant loss of life. Existing treatments that can be repurposed as prophylactic and therapeutic agents may reduce the pandemic's devastation. Emerging evidence of potential applications in other therapeutic contexts has led to the investigation of dietary supplements and nutraceuticals for COVID-19. Such products include vitamin C, vitamin D, omega 3 polyunsaturated fatty acids, probiotics, and zinc, all of which are currently under clinical investigation. In this review, we critically appraise the evidence surrounding dietary supplements and nutraceuticals for the prophylaxis and treatment of COVID-19. Overall, further study is required before evidence-based recommendations can be formulated, but nutritional status plays a significant role in patient outcomes, and these products may help alleviate deficiencies. For example, evidence indicates that vitamin D deficiency may be associated with a greater incidence of infection and severity of COVID-19, suggesting that vitamin D supplementation may hold prophylactic or therapeutic value. A growing number of scientific organizations are now considering recommending vitamin D supplementation to those at high risk of COVID-19. Because research in vitamin D and other nutraceuticals and supplements is preliminary, here we evaluate the extent to which these nutraceutical and dietary supplements hold potential in the COVID-19 crisis.IMPORTANCE Sales of dietary supplements and nutraceuticals have increased during the pandemic due to their perceived "immune-boosting" effects. However, little is known about the efficacy of these dietary supplements and nutraceuticals against the novel coronavirus (severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2]) or the disease that it causes, CoV disease 2019 (COVID-19). This review provides a critical overview of the potential prophylactic and therapeutic value of various dietary supplements and nutraceuticals from the evidence available to date. These include vitamin C, vitamin D, and zinc, which are often perceived by the public as treating respiratory infections or supporting immune health. Consumers need to be aware of misinformation and false promises surrounding some supplements, which may be subject to limited regulation by authorities. However, considerably more research is required to determine whether dietary supplements and nutraceuticals exhibit prophylactic and therapeutic value against SARS-CoV-2 infection and COVID-19. This review provides perspective on which nutraceuticals and supplements are involved in biological processes that are relevant to recovery from or prevention of COVID-19.

Vasculitis and Neutrophil Extracellular Traps in Lungs of Golden Syrian Hamsters With SARS-CoV-2

Neutrophil extracellular traps (NETs) have been identified as one pathogenetic trigger in severe COVID-19 cases and therefore well-described animal models to understand the influence of NETs in COVID-19 pathogenesis are needed. SARS-CoV-2 infection causes infection and interstitial pneumonia of varying severity in humans and COVID-19 models. Pulmonary as well as peripheral vascular lesions represent a severe, sometimes fatal, disease complication of unknown pathogenesis in COVID-19 patients. Furthermore, neutrophil extracellular traps (NETs), which are known to contribute to vessel inflammation or endothelial damage, have also been shown as potential driver of COVID-19 in humans. Though most studies in animal models describe the pulmonary lesions characterized by interstitial inflammation, type II pneumocyte hyperplasia, edema, fibrin formation and infiltration of macrophages and neutrophils, detailed pathological description of vascular lesions or NETs in COVID-19 animal models are lacking so far. Here we report different types of pulmonary vascular lesions in the golden Syrian hamster model of COVID-19. Vascular lesions included endothelialitis and vasculitis at 3 and 6 days post infection (dpi), and were almost nearly resolved at 14 dpi. Importantly, virus antigen was present in pulmonary lesions, but lacking in vascular alterations. In good correlation to these data, NETs were detected in the lungs of infected animals at 3 and 6 dpi. Hence, the Syrian hamster seems to represent a useful model to further investigate the role of vascular lesions and NETs in COVID-19 pathogenesis.

Prediction of Sepsis in COVID-19 Using Laboratory Indicators

Background

The outbreak of coronavirus disease 2019 (COVID-19) has become a global public health concern. Many inpatients with COVID-19 have shown clinical symptoms related to sepsis, which will aggravate the deterioration of patients’ condition. We aim to diagnose Viral Sepsis Caused by SARS-CoV-2 by analyzing laboratory test data of patients with COVID-19 and establish an early predictive model for sepsis risk among patients with COVID-19.

Methods

This study retrospectively investigated laboratory test data of 2,453 patients with COVID-19 from electronic health records. Extreme gradient boosting (XGBoost) was employed to build four models with different feature subsets of a total of 69 collected indicators. Meanwhile, the explainable Shapley Additive ePlanation (SHAP) method was adopted to interpret predictive results and to analyze the feature importance of risk factors.

Findings

The model for classifying COVID-19 viral sepsis with seven coagulation function indicators achieved the area under the receiver operating characteristic curve (AUC) 0.9213 (95% CI, 89.94–94.31%), sensitivity 97.17% (95% CI, 94.97–98.46%), and specificity 82.05% (95% CI, 77.24–86.06%). The model for identifying COVID-19 coagulation disorders with eight features provided an average of 3.68 (±) 4.60 days in advance for early warning prediction with 0.9298 AUC (95% CI, 86.91–99.04%), 82.22% sensitivity (95% CI, 67.41–91.49%), and 84.00% specificity (95% CI, 63.08–94.75%).

Interpretation

We found that an abnormality of the coagulation function was related to the occurrence of sepsis and the other routine laboratory test represented by inflammatory factors had a moderate predictive value on coagulopathy, which indicated that early warning of sepsis in COVID-19 patients could be achieved by our established model to improve the patient’s prognosis and to reduce mortality.

Protease-activated receptor 1 as a potential therapeutic target for COVID-19

Acute respiratory disease caused by a novel coronavirus (SARS-CoV-2) has spread all over the world, since its discovery in 2019, Wuhan, China. This disease is called COVID-19 and already killed over 1 million people worldwide. The clinical symptoms include fever, dry cough, dyspnea, headache, dizziness, generalized weakness, vomiting, and diarrhea. Unfortunately, so far, there is no validated vaccine, and its management consists mainly of supportive care. Venous thrombosis and pulmonary embolism are highly prevalent in patients suffering from severe COVID-19. In fact, a prothrombotic state seems to be present in most fatal cases of the disease. SARS-CoV-2 leads to the production of proinflammatory cytokines, causing immune-mediated tissue damage, disruption of the endothelial barrier, and uncontrolled thrombogenesis. Thrombin is the key regulator of coagulation and fibrin formation. In severe COVID-19, a dysfunctional of physiological anticoagulant mechanisms leads to a progressive increase of thrombin activity, which is associated with acute respiratory distress syndrome development and a poor prognosis. Protease-activated receptor type 1 (PAR1) is the main thrombin receptor and may represent an essential link between coagulation and inflammation in the pathophysiology of COVID-19. In this review, we discuss the potential role of PAR1 inhibition and regulation in COVID-19 treatment.

Dietary Supplements and Nutraceuticals Under Investigation for COVID-19 Prevention and Treatment

Coronavirus disease 2019 (COVID-19) has caused global disruption and a significant loss of life. Existing treatments that can be repurposed as prophylactic and therapeutic agents could reduce the pandemic's devastation. Emerging evidence of potential applications in other therapeutic contexts has led to the investigation of dietary supplements and nutraceuticals for COVID-19. Such products include vitamin C, vitamin D, omega 3 polyunsaturated fatty acids, probiotics, and zinc, all of which are currently under clinical investigation. In this review, we critically appraise the evidence surrounding dietary supplements and nutraceuticals for the prophylaxis and treatment of COVID-19. Overall, further study is required before evidence-based recommendations can be formulated, but nutritional status plays a significant role in patient outcomes, and these products could help alleviate deficiencies. For example, evidence indicates that vitamin D deficiency may be associated with greater incidence of infection and severity of COVID-19, suggesting that vitamin D supplementation may hold prophylactic or therapeutic value. A growing number of scientific organizations are now considering recommending vitamin D supplementation to those at high risk of COVID-19. Because research in vitamin D and other nutraceuticals and supplements is preliminary, here we evaluate the extent to which these nutraceutical and dietary supplements hold potential in the COVID-19 crisis.

The Emerging Role of Vitamin C in the Prevention and Treatment of COVID-19

Investigation into the role of vitamin C in the prevention and treatment of pneumonia and sepsis has been underway for many decades. This research has laid a strong foundation for translation of these findings into patients with severe coronavirus disease (COVID-19). Research has indicated that patients with pneumonia and sepsis have low vitamin C status and elevated oxidative stress. Administration of vitamin C to patients with pneumonia can decrease the severity and duration of the disease. Critically ill patients with sepsis require intravenous administration of gram amounts of the vitamin to normalize plasma levels, an intervention that some studies suggest reduces mortality. The vitamin has pleiotropic physiological functions, many of which are relevant to COVID-19. These include its antioxidant, anti-inflammatory, antithrombotic and immuno-modulatory functions. Preliminary observational studies indicate low vitamin C status in critically ill patients with COVID-19. There are currently a number of randomized controlled trials (RCTs) registered globally that are assessing intravenous vitamin C monotherapy in patients with COVID-19. Since hypovitaminosis C and deficiency are common in low-middle-income settings, and many of the risk factors for vitamin C deficiency overlap with COVID-19 risk factors, it is possible that trials carried out in populations with chronic hypovitaminosis C may show greater efficacy. This is particularly relevant for the global research effort since COVID-19 is disproportionately affecting low-middle-income countries and low-income groups globally. One small trial from China has finished early and the findings are currently under peer review. There was significantly decreased mortality in the more severely ill patients who received vitamin C intervention. The upcoming findings from the larger RCTs currently underway will provide more definitive evidence. Optimization of the intervention protocols in future trials, e.g., earlier and sustained administration, is warranted to potentially improve its efficacy. Due to the excellent safety profile, low cost, and potential for rapid upscaling of production, administration of vitamin C to patients with hypovitaminosis C and severe respiratory infections, e.g., COVID-19, appears warranted.