Autonomic cardiac function in children and adolescents with long COVID: a case-controlled study

Although the mechanisms underlying the pathophysiology of long COVID condition are still debated, there is growing evidence that autonomic dysfunction may play a role in the long-term complications or persisting symptoms observed in a significant proportion of patients after SARS-CoV-2 infection. However, studies focused on autonomic dysfunction have primarily been conducted in adults, while autonomic function has not yet been investigated in pediatric subjects. In this study, for the first time, we assessed whether pediatric patients with long COVID present abnormalities in autonomic cardiac function. Fifty-six long COVID pediatric patients (mean age 10.3 ± 3.8 y) and 27 age-, sex-, and body surface area-matched healthy controls (mean age 10.4 ± 4.5y) underwent a standard 12-lead electrocardiography (ECG) and 24-h ECG Holter monitoring. Autonomic cardiac function was assessed by time-domain and frequency-domain heart rate variability parameters. A comprehensive echocardiographic study was also obtained by two-dimensional echocardiography and tissue Doppler imaging. Data analysis showed that pediatric patients with long COVID had significant changes in HRV variables compared to healthy controls: significantly lower r-MSSD (root mean square of successive RR interval differences, 47.4 ± 16.9 versus 60.4 ± 29.1, p = 0.02), significant higher values VLF (very low frequency, 2077.8 ± 1023.3 versus 494.3 ± 1015.5 ms, p = 0.000), LF (low frequency, 1340.3 ± 635.6 versus 354.6 ± 816.8 ms, p = 0.000), and HF (high frequency, 895.7 ± 575.8 versus 278.9 ± 616.7 ms, p = 0.000). No significant differences were observed between the two groups both in systolic and diastolic parameters by echocardiography.  Conclusion: These findings suggest that pediatric patients with long COVID have an imbalance of cardiac autonomic function toward a relative predominance of parasympathetic tone, as already reported in adult patients with long COVID. Further studies are needed to clarify the clinical significance of this autonomic dysfunction and demonstrate its role as a pathophysiological mechanism of long COVID, paving the way for effective therapeutic and preventive strategies. What is Known: • Long Covid in children has been described globally, but studies have mostly focused on collecting the temporal evolution of persisting symptoms. What is New: • Cardiac autonomic imbalance toward a relative predominance of parasympathetic tone is a mechanism underlying Long Covid in children, as also described in adults.

Long-term findings on working memory neural dynamics in healthcare workers after mild COVID-19

OBJECTIVE

Understanding the long-term impact of Coronavirus Disease 2019 (COVID-19) on cognitive function, even in mild cases, is critical to the well-being of individuals, especially for healthcare workers who are at increased risk of exposure to the virus. To the best of our knowledge, the electrophysiological activity underlying cognitive functioning has not yet been explored.

METHODS

Seventy-seven healthcare workers took part in the study (43 with mild infection about one year before the study and 34 uninfected). To assess cognitive status, event-related potentials (ERPs) and behavioural responses were recorded while participants performed a working memory task.

RESULTS

COVID-19 participants exhibited a distinct neural pattern with lower parieto-occipital N1 amplitudes and higher frontal P2 amplitudes as compared to non-infected healthcare workers. We found no behavioural differences (reaction times and error rates) in working memory functioning between groups.

CONCLUSIONS

This neural pattern suggests the presence of a decrement of processing resources linked to the encoding of sensory information (N1), followed by the enhanced of the P2 response which could be interpreted as the activation of compensation mechanism in COVID-19 participants.

SIGNIFICANCE

The current findings point out that ERPs could serve as valuable neural indices for detecting distinctive patterns in working memory functioning of COVID-19 participants, even in mild cases. However, further research is required to precisely ascertain the long-term cognitive effects of COVID-19 beyond one-year post-infection.

Resting-state EEG rhythms are abnormal in post COVID-19 patients with brain fog without cognitive and affective disorders

OBJECTIVES

Several persons experiencing post-covid-19 (post-COVID) with "brain fog" (e.g., fatigue, cognitive and psychiatric disorders, etc.) show abnormal resting-state electroencephalographic (rsEEG) rhythms reflecting a vigilance dysfunction. Here, we tested the hypothesis that in those post-COVID persons, abnormal rsEEG rhythms may occur even when cognitive and psychiatric disorders are absent.

METHODS

The experiments were performed on post-COVID participants about one year after hospitalization for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Inclusion criteria included a "brain fog" claim, no pre-infection, and actual organic chronic disease. Matched controls (no COVID) were also enrolled. All participants underwent clinical/neuropsychological assessment (including fatigue assessment) and rsEEG recordings. The eLORETA freeware estimated regional rsEEG cortical sources at individual delta (<4 Hz), theta (4-7 Hz), and alpha (8-13 Hz) bands. Beta (14-30 Hz) and gamma (30-40 Hz) bands were pre-fixed.

RESULTS

More than 90% of all post-COVID participants showed no cognitive or psychiatric disorders, and 75% showed ≥ 2 fatigue symptoms. The post-COVID group globally presented lower posterior rsEEG alpha source activities than the Control group. This effect was more significant in the long COVID-19 patients with ≥ 2 fatigue symptoms.

CONCLUSIONS

In post-COVID patients with no chronic diseases and cognitive/psychiatric disorders, "brain fog" can be associated with abnormal posterior rsEEG alpha rhythms and subjective fatigue.

SIGNIFICANCE

These abnormalities may be related to vigilance and allostatic dysfunctions.

Long COVID exhibits clinically distinct phenotypes at 3-6 months post-SARS-CoV-2 infection: results from the P4O2 consortium

BACKGROUND

Four months after SARS-CoV-2 infection, 22%-50% of COVID-19 patients still experience complaints. Long COVID is a heterogeneous disease and finding subtypes could aid in optimising and developing treatment for the individual patient.

METHODS

Data were collected from 95 patients in the P4O2 COVID-19 cohort at 3-6 months after infection. Unsupervised hierarchical clustering was performed on patient characteristics, characteristics from acute SARS-CoV-2 infection, long COVID symptom data, lung function and questionnaires describing the impact and severity of long COVID. To assess robustness, partitioning around medoids was used as alternative clustering.

RESULTS

Three distinct clusters of patients with long COVID were revealed. Cluster 1 (44%) represented predominantly female patients (93%) with pre-existing asthma and suffered from a median of four symptom categories, including fatigue and respiratory and neurological symptoms. They showed a milder SARS-CoV-2 infection. Cluster 2 (38%) consisted of predominantly male patients (83%) with cardiovascular disease (CVD) and suffered from a median of three symptom categories, most commonly respiratory and neurological symptoms. This cluster also showed a significantly lower forced expiratory volume within 1 s and diffusion capacity of the lung for carbon monoxide. Cluster 3 (18%) was predominantly male (88%) with pre-existing CVD and diabetes. This cluster showed the mildest long COVID, and suffered from symptoms in a median of one symptom category.

CONCLUSIONS

Long COVID patients can be clustered into three distinct phenotypes based on their clinical presentation and easily obtainable information. These clusters show distinction in patient characteristics, lung function, long COVID severity and acute SARS-CoV-2 infection severity. This clustering can help in selecting the most beneficial monitoring and/or treatment strategies for patients suffering from long COVID. Follow-up research is needed to reveal the underlying molecular mechanisms implicated in the different phenotypes and determine the efficacy of treatment.

Lower airway microbiota compositions differ between influenza, COVID-19 and bacteria-related acute respiratory distress syndromes

BACKGROUND

Acute respiratory distress syndrome (ARDS) is responsible for 400,000 deaths annually worldwide. Few improvements have been made despite five decades of research, partially because ARDS is a highly heterogeneous syndrome including various types of aetiologies. Lower airway microbiota is involved in chronic inflammatory diseases and recent data suggest that it could also play a role in ARDS. Nevertheless, whether the lower airway microbiota composition varies between the aetiologies of ARDS remain unknown. The aim of this study is to compare lower airway microbiota composition between ARDS aetiologies, i.e. pulmonary ARDS due to influenza, SARS-CoV-2 or bacterial infection.

METHODS

Consecutive ARDS patients according to Berlin's classification requiring invasive ventilation with PCR-confirmed influenza or SARS-CoV-2 infections and bacterial infections (> 105 CFU/mL on endotracheal aspirate) were included. Endotracheal aspirate was collected at admission, V3-V4 and ITS2 regions amplified by PCR, deep-sequencing performed on MiSeq sequencer (Illumina®) and data analysed using DADA2 pipeline.

RESULTS

Fifty-three patients were included, 24 COVID-19, 18 influenza, and 11 bacterial CAP-related ARDS. The lower airway bacteriobiota and mycobiota compositions (β-diversity) were dissimilar between the three groups (p = 0.05 and p = 0.01, respectively). The bacterial α-diversity was significantly lower in the bacterial CAP-related ARDS group compared to the COVID-19 ARDS group (p = 0.04). In contrast, influenza-related ARDS patients had higher lung mycobiota α-diversity than the COVID-19-related ARDS (p = 0 < 01).

CONCLUSION

Composition of lower airway microbiota (both microbiota and mycobiota) differs between influenza, COVID-19 and bacterial CAP-related ARDS. Future studies investigating the role of lung microbiota in ARDS pathophysiology should take aetiology into account.

Pathophysiological Mechanisms in Long COVID: A Mixed Method Systematic Review

INTRODUCTION

Long COVID (LC) is a global public health crisis affecting more than 70 million people. There is emerging evidence of different pathophysiological mechanisms driving the wide array of symptoms in LC. Understanding the relationships between mechanisms and symptoms helps in guiding clinical management and identifying potential treatment targets.

METHODS

This was a mixed-methods systematic review with two stages: Stage one (Review 1) included only existing systematic reviews (meta-review) and Stage two (Review 2) was a review of all primary studies. The search strategy involved Medline, Embase, Emcare, and CINAHL databases to identify studies that described symptoms and pathophysiological mechanisms with statistical analysis and/or discussion of plausible causal relationships between mechanisms and symptoms. Only studies that included a control arm for comparison were included. Studies were assessed for quality using the National Heart, Lung, and Blood Institute quality assessment tools.

RESULTS

19 systematic reviews were included in Review 1 and 46 primary studies in Review 2. Overall, the quality of reporting across the studies included in this second review was moderate to poor. The pathophysiological mechanisms with strong evidence were immune system dysregulation, cerebral hypoperfusion, and impaired gas transfer in the lungs. Other mechanisms with moderate to weak evidence were endothelial damage and hypercoagulation, mast cell activation, and auto-immunity to vascular receptors.

CONCLUSIONS

LC is a complex condition affecting multiple organs with diverse clinical presentations (or traits) underpinned by multiple pathophysiological mechanisms. A 'treatable trait' approach may help identify certain groups and target specific interventions. Future research must include understanding the response to intervention based on these mechanism-based traits.

SARS-CoV-2 sneezing explained

Viral protein prods nerve cells, may be treatment target.

Cognitive and brain connectivity trajectories in critically ill COVID-19 patients

BACKGROUND

Multiple Organ failure (MOF) is one of the main causes of admission to the Intensive Care Unit (ICU) of patients infected with COVID-19 and can cause short- and long-term neurological deficits.

OBJECTIVE

To compare the cognitive functioning and functional brain connectivity at 6-12 months after discharge in two groups of individuals with MOF, one due to COVID-19 and the other due to another cause (MOF-group), with a group of Healthy Controls (HC).

METHODS

Thirty-six participants, 12 from each group, underwent a neuropsychological and neuroimaging assessment at both time-points. Functional connectivity of the resting state networks was compared between COVID-19 and HC while controlling for the effect of MOF. The association between functional connectivity and neuropsychological performance was also investigated.

RESULTS

Compared to the HC, COVID-19 group demonstrated hypoconnectivity between the Default Mode Network and Salience Network. This pattern was associated with worse performance on tests of attention and information processing speed, at both time-points.

CONCLUSION

The study of the association between cognitive function and brain functional connectivity in COVID-19 allows the understanding of the short- and long-term neurological alterations of this disease and promotes the development of intervention programs to improve the quality of life for this understudied population.

Effects of a pulmonary rehabilitation program on pulmonary function, exercise performance, and quality of life in patients with severe COVID-19

BACKGROUND

Severe coronavirus 2019 disease (COVID-19) causes acute hypoxemic respiratory failure requiring invasive mechanical ventilation (IMV). Once these symptoms are resolved, patients can present systemic deterioration.

OBJECTIVE

The two objectives of this study were as follows: to describe the results of a pulmonary rehabilitation program (PRP), which is divided into three groups with different numbers of sessions (12, 24, and 36), and to associate the variables of pulmonary function, exercise performance, and functionality with the number of sessions and functional improvement.

DESIGN

Prospective, observational study.

METHODS

PRP consisted of aerobic + strength + flexibility exercises under the supervision and individualized into 12, 24, or 36 sessions (12s, 24s, and 36s), depending on the evolution of each patient. At the beginning of the study and immediately after the intervention, forced vital capacity (FVC), maximal inspiratory pressure, 6-minute walk test (6MWT), sit-to-stand test (STS), maximal handgrip strength (HGS), Fatigue Assessment Scale, Post-COVID-19 Functional Status (PCFS), and health-related quality of life (HRQoL) were measured.

RESULTS

The proposed PRP demonstrated a positive effect on pulmonary function, exercise performance, and HRQoL, regardless of the number of sessions. A higher score on the PCFS and more days on IMV were associated with the increased likelihood of needing more sessions, whereas more meters on the 6MWT in the initial evaluation was associated with a reduced likelihood of needing more sessions. Finally, more repetitions on the STS and less distance covered on the initial 6MWT were associated with a greater improvement in exercise performance evaluated with the 6MWT.

CONCLUSION

Supervised and individualized PRP for patients with severe post-COVID-19 improves pulmonary function, exercise performance, functionality, and quality of life. Functionality, distance covered on the 6MWT, and the days on IMV are central to the scheduling of the number of sessions for these patients.

Assessment of thermal and temporal stability of SARS-CoV-2 samples using real-time qRT-PCR

BACKGROUND

As per the guidelines of the Indian Council of Medical Research, nasopharyngeal and oropharyngeal swabs in viral transport medium (VTM) are to be stored at 4 °C for less than 5 days and for more than 5 days at -70 °C. Samples are not transported or stored as per prescribed conditions because of the limitations, resulting in an apprehensive diagnosis. The aim of the study was to test the stability of the SARS-CoV-2 sample stored in VTM at different temperatures.

METHODS

In this study, the stability of 21 positive and 9 negative samples for SARS-CoV-2 was evaluated in commercial VTM at different temperatures (-80 °C, -20 °C, 4 °C, and 25 to 30 °C). Stability was checked for up to 50 days in the above storage conditions at different intervals. PathoDetect™ and Hi-PCR® kits were used for the detection of the four genes of SARS-CoV-2. The Cycle Threshold (Ct) value for determining the positivity of samples for PathoDetect™ was < 40 and for Hi-PCR® was < 38.

RESULTS

The SARS-CoV-2 confirmatory genes (RdRp and E genes) and the internal housekeeping gene remained detectable even on the 50th day of the study. The Ct of the RdRp and E genes were found to increase with storage duration, but all positive samples remained positive till the end of the study, or the Ct value remained below the cut-off level. The negative samples gave consistent results until the end of the study. When the differences in Ct values were compared between the days in a set of experiments, they were not significantly different except in a few samples.

CONCLUSION

The SARS-CoV-2 genetic materials in commercial VTM were stable at room temperature to -80 °C for 50 days.

Geringe α-Thrombin/GPIbα-Interaktion trägt möglicherweise zur Hyperreaktivität der Thrombozyten bei COVID-19-Patienten bei

Mehrere Studien haben gezeigt, dass Thrombozyten mit dem SARSCoV-2 Coronavirus interagieren können. In der Folge kommt es zum programmierten Zelltod, zur Freisetzung extrazellulärer Vesikel und zu einer erhöhten Thrombozytenreaktivität bei Patienten mit der Coronavirus-Krankheit-2019 (COVID-19) als Reaktion auf niedrige Dosen von α-Thrombin.

A common allele of HLA is associated with asymptomatic SARS-CoV-2 infection

Studies have demonstrated that at least 20% of individuals infected with SARS-CoV-2 remain asymptomatic1-4. Although most global efforts have focused on severe illness in COVID-19, examining asymptomatic infection provides a unique opportunity to consider early immunological features that promote rapid viral clearance. Here, postulating that variation in the human leukocyte antigen (HLA) loci may underly processes mediating asymptomatic infection, we enrolled 29,947 individuals, for whom high-resolution HLA genotyping data were available, in a smartphone-based study designed to track COVID-19 symptoms and outcomes. Our discovery cohort (n = 1,428) comprised unvaccinated individuals who reported a positive test result for SARS-CoV-2. We tested for association of five HLA loci with disease course and identified a strong association between HLA-B*15:01 and asymptomatic infection, observed in two independent cohorts. Suggesting that this genetic association is due to pre-existing T cell immunity, we show that T cells from pre-pandemic samples from individuals carrying HLA-B*15:01 were reactive to the immunodominant SARS-CoV-2 S-derived peptide NQKLIANQF. The majority of the reactive T cells displayed a memory phenotype, were highly polyfunctional and were cross-reactive to a peptide derived from seasonal coronaviruses. The crystal structure of HLA-B*15:01-peptide complexes demonstrates that the peptides NQKLIANQF and NQKLIANAF (from OC43-CoV and HKU1-CoV) share a similar ability to be stabilized and presented by HLA-B*15:01. Finally, we show that the structural similarity of the peptides underpins T cell cross-reactivity of high-affinity public T cell receptors, providing the molecular basis for HLA-B*15:01-mediated pre-existing immunity.

Identification of natural killer markers associated with fatal outcome in COVID-19 patients

Introduction

Increasing evidence has shown that coronavirus disease 19 (COVID-19) severity is driven by a dysregulated immunological response. Previous studies have demonstrated that natural killer (NK) cell dysfunction underpins severe illness in COVID-19 patients, but have lacked an in-depth analysis of NK cell markers as a driver of death in the most critically ill patients.

Methods

We enrolled 50 non-vaccinated hospitalized patients infected with the initial virus or the alpha variant of SARS-CoV-2 with moderate or severe illness, to evaluate phenotypic and functional features of NK cells.

Results

Here, we show that, consistent with previous studies, evolution NK cells from COVID-19 patients are more activated, with the decreased activation of natural cytotoxicity receptors and impaired cytotoxicity and IFN-γ production, in association with disease regardless of the SARS-CoV-2 strain. Fatality was observed in 6 of 17 patients with severe disease; NK cells from all of these patients displayed a peculiar phenotype of an activated memory-like phenotype associated with massive TNF-α production.

Discussion

These data suggest that fatal COVID-19 infection is driven by an uncoordinated inflammatory response in part mediated by a specific subset of activated NK cells.

Renin-Angiotensin System Modulation With Synthetic Angiotensin (1-7) and Angiotensin II Type 1 Receptor-Biased Ligand in Adults With COVID-19: Two Randomized Clinical Trials

Importance

Preclinical models suggest dysregulation of the renin-angiotensin system (RAS) caused by SARS-CoV-2 infection may increase the relative activity of angiotensin II compared with angiotensin (1-7) and may be an important contributor to COVID-19 pathophysiology.

Objective

To evaluate the efficacy and safety of RAS modulation using 2 investigational RAS agents, TXA-127 (synthetic angiotensin [1-7]) and TRV-027 (an angiotensin II type 1 receptor-biased ligand), that are hypothesized to potentiate the action of angiotensin (1-7) and mitigate the action of the angiotensin II.

Design, Setting, and Participants

Two randomized clinical trials including adults hospitalized with acute COVID-19 and new-onset hypoxemia were conducted at 35 sites in the US between July 22, 2021, and April 20, 2022; last follow-up visit: July 26, 2022.

Interventions

A 0.5-mg/kg intravenous infusion of TXA-127 once daily for 5 days or placebo. A 12-mg/h continuous intravenous infusion of TRV-027 for 5 days or placebo.

Main Outcomes and Measures

The primary outcome was oxygen-free days, an ordinal outcome that classifies a patient's status at day 28 based on mortality and duration of supplemental oxygen use; an adjusted odds ratio (OR) greater than 1.0 indicated superiority of the RAS agent vs placebo. A key secondary outcome was 28-day all-cause mortality. Safety outcomes included allergic reaction, new kidney replacement therapy, and hypotension.

Results

Both trials met prespecified early stopping criteria for a low probability of efficacy. Of 343 patients in the TXA-127 trial (226 [65.9%] aged 31-64 years, 200 [58.3%] men, 225 [65.6%] White, and 274 [79.9%] not Hispanic), 170 received TXA-127 and 173 received placebo. Of 290 patients in the TRV-027 trial (199 [68.6%] aged 31-64 years, 168 [57.9%] men, 195 [67.2%] White, and 225 [77.6%] not Hispanic), 145 received TRV-027 and 145 received placebo. Compared with placebo, both TXA-127 (unadjusted mean difference, -2.3 [95% CrI, -4.8 to 0.2]; adjusted OR, 0.88 [95% CrI, 0.59 to 1.30]) and TRV-027 (unadjusted mean difference, -2.4 [95% CrI, -5.1 to 0.3]; adjusted OR, 0.74 [95% CrI, 0.48 to 1.13]) resulted in no difference in oxygen-free days. In the TXA-127 trial, 28-day all-cause mortality occurred in 22 of 163 patients (13.5%) in the TXA-127 group vs 22 of 166 patients (13.3%) in the placebo group (adjusted OR, 0.83 [95% CrI, 0.41 to 1.66]). In the TRV-027 trial, 28-day all-cause mortality occurred in 29 of 141 patients (20.6%) in the TRV-027 group vs 18 of 140 patients (12.9%) in the placebo group (adjusted OR, 1.52 [95% CrI, 0.75 to 3.08]). The frequency of the safety outcomes was similar with either TXA-127 or TRV-027 vs placebo.

Conclusions and Relevance

In adults with severe COVID-19, RAS modulation (TXA-127 or TRV-027) did not improve oxygen-free days vs placebo. These results do not support the hypotheses that pharmacological interventions that selectively block the angiotensin II type 1 receptor or increase angiotensin (1-7) improve outcomes for patients with severe COVID-19.

Trial Registration

ClinicalTrials.gov Identifier: NCT04924660.

Headache as a COVID-19 onset symptom or Post-COVID symptom according to the SARS-CoV-2 Variant

INTRODUCTION

COVID19 associated headaches are highly common and there is currently an unmet need to better understand their association with SARSCoV2 variants. Headaches are a prevalent symptom in the acute phase of COVID19 and are associated with a better prognosis and better immune response. They are also a relevant post-COVID symptom.

AREAS COVERED

This article analyses the differences in the prevalence of headache as an onset symptom and in post-COVID headache among the different SARS-CoV-2 variants: the historical strain, Alpha, Delta and Omicron. The different pathophysiological mechanisms by which SARS-CoV-2 infection may cause headache are also discussed.

EXPERT OPINION

The presence of headache at the acute phase is a risk factor for post-COVID headache, whereas a history of primary headache does not appear to be associated with post-COVID headache. The prevalence of headache as an onset symptom appears to be variable for the different SARS-CoV-2 variants, but current data are inconclusive. However, the current evidence also suggests that headache represents a prevalent symptom in the acute and post-infection COVID-19 phase, regardless of SARS-CoV-2 variant.

The role of free vitamin D and vitamin D binding protein in SARS-Cov-2 infection in children

BACKGROUND

Many studies have discussed the effects of serum vitamin D deficiency in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) patients. This study aimed to investigate the relationship between SARS-CoV-2 infection severity and free vitamin D (FVD) and bioavailable vitamin D (BAVD) levels in children.

METHODS

A prospective case-control study design was used. Participants were divided into three groups based on the World Health Organization COVID-19 Clinical Progression Scale. Serum 25-hydroxyvitamin D (ng/mL), albumin (g/L), and vitamin D binding protein (ng/mL) levels were evaluated to investigate the relationship between disease severity and FVD and BAVD levels.

RESULTS

In total, 82 participants were included in the study. Of those, 24.4% were uninfected (n = 20), 50% had a mild case of SARS-CoV-2 (n = 41), and 25.6% had a moderate case (n = 21). There was a statistically significant difference in FVD and BAVD levels between the groups (p = 0.026). Median FVD (p = 0.007, Cohen's d = 0.84) and BAVD (p = 0.007, Cohen's d = 0.86) levels were significantly higher in the mild group compared to the moderate group. FVD and BAVD metabolites were moderately positively correlated with lymphocyte counts (FVD: r = 0.437, p < 0.001; BAVD: r = 0.439, p < 0.001).

CONCLUSIONS

This is the first study to demonstrate a relationship between SARS-CoV-2 symptom severity and FVD and BAVD levels. The relationship between FVD and BAVD levels and lymphocyte counts could play an important role in symptom severity and should be evaluated in further studies.

Recent Progress in Research on COVID-19 Pathophysiology: Biomarkers, Repurposed Drugs, Viral Invasiveness, SARS-CoV-2 Genetic Diversity, the Crystal Structure of Viral Proteins, and the Molecular and Cellular Outcomes of COVID-19

COVID-19 is a disease caused by a novel zoonotic germ known as SARS-CoV-2 coronavirus [...].

COVID-19 and Gut Injury

COVID-19 induced by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is currently a pandemic and it has led to more than 620 million patients with 6.56 million deaths globally. Males are more susceptible to COVID-19 infection and associated with a higher chance to develop severe COVID-19 than females. Aged people are at a high risk of COVID-19 infection, while young children have also increased cases. COVID-19 patients typically develop respiratory system pathologies, however symptoms in the gastrointestinal (GI) tract are also very common. Inflammatory cell recruitments and their secreted cytokines are found in the GI tract in COVID-19 patients. Microbiota changes are the key feature in COVID-19 patients with gut injury. Here, we review all current known mechanisms of COVID-19-induced gut injury, and the most acceptable one is that SARS-CoV-2 binds to angiotensin-converting enzyme 2 (ACE2) receptor on host cells in the GI tract. Interestingly, inflammatory bowel disease (IBD) is an inflammatory disorder, but the patients with IBD do not have the increased risk to develop COVID-19. There is currently no cure for COVID-19, but anti-viruses and monoclonal antibodies reduce viral load and shorten the recovery time of the disease. We summarize current therapeutics that target symptoms in the GI tract, including probiotics, ACE2 inhibitors and nutrients. These are promising therapeutic options for COVID-19-induced gut injury.

Individual genetic variability mainly of Proinflammatory cytokines, cytokine receptors, and toll-like receptors dictates pathophysiology of COVID-19 disease

Innate and acquired immunity responses are crucial for viral infection elimination. However, genetic variations in coding genes may exacerbate the inflammation or initiate devastating cytokine storms which poses severe respiratory conditions in coronavirus disease-19 (COVID-19). Host genetic variations in particular those related to the immune responses determine the patients' susceptibility and COVID-19 severity and pathophysiology. Gene polymorphisms such as single nucleotide polymorphisms (SNPs) of interferons, TNF, IL1, IL4, IL6, IL7, IL10, and IL17 predispose patients to the severe form of COVID-19 or severe acute respiratory syndrome coronavirus-2 (SARS-COV-2). These variations mainly alter the gene expression and cause a severe response by B cells, T cells, monocytes, neutrophils, and natural killer cells participating in a cytokine storm. Moreover, cytokines and chemokines SNPs are associated with the severity of COVID-19 and clinical outcomes depending on the corresponding effect. Additionally, genetic variations in genes encoding toll-like receptors (TLRs) mainly TLR3, TLR7, and TLR9 have been related to the COVID-19 severe respiratory symptoms. The specific relation of these mutations with the novel variants of concern (VOCs) infection remains to be elucidated. Genetic variations mainly within genes encoding proinflammatory cytokines, cytokine receptors, and TLRs predispose patients to COVID-19 disease severity. Understanding host immune gene variations associated with the SARS-COV-2 infection opens insights to control the pathophysiology of emerging viral infections.

[Long COVID: nosographic aspects and clinical epidemiology]

Recent evidence shows that a range of persistent or new symptoms can manifest after 4-12 weeks in a subset of patients who have recovered from acute SARS-CoV-2 infection, and this condition has been coined long COVID by COVID-19 survivors among social support groups. Long COVID can affect the whole spectrum of people with COVID-19, from those with very mild acute disease to the most severe forms. Like the acute form, long COVID has multisystemic aspects. Patients can manifest with a very heterogeneous multitude of symptoms, including fatigue, post-exertional malaise, dyspnea, cognitive impairment, sleep disturbances, anxiety and depression, muscle pain, brain fog, anosmia/dysgeusia, headache, and limitation of functional capacity, which impact their quality of life. Because of the extreme clinical heterogeneity, and also due to the lack of a shared, specific definition, it is very difficult to know the real prevalence and incidence of this condition. Risk factors for developing long COVID would be female sex, initial severity, and comorbidities. Globally, with the re-emergence of new waves, the population of people infected with SARS-CoV-2 continues to expand rapidly, necessitating a more thorough understanding of potential sequelae of COVID-19. This review summarizes up to date definitions and epidemiological aspects of long COVID.

Antibiotic-Induced Primary Biles Inhibit SARS-CoV-2 Endoribonuclease Nsp15 Activity in Mouse Gut

The gut microbiome profile of COVID-19 patients was found to correlate with a viral load of SARS-CoV-2, COVID-19 severity, and dysfunctional immune responses, suggesting that gut microbiota may be involved in anti-infection. In order to investigate the role of gut microbiota in anti-infection against SARS-CoV-2, we established a high-throughput in vitro screening system for COVID-19 therapeutics by targeting the endoribonuclease (Nsp15). We also evaluated the activity inhibition of the target by substances of intestinal origin, using a mouse model in an attempt to explore the interactions between gut microbiota and SARS-CoV-2. The results unexpectedly revealed that antibiotic treatment induced the appearance of substances with Nsp15 activity inhibition in the intestine of mice. Comprehensive analysis based on functional profiling of the fecal metagenomes and endoribonuclease assay of antibiotic-enriched bacteria and metabolites demonstrated that the Nsp15 inhibitors were the primary bile acids that accumulated in the gut as a result of antibiotic-induced deficiency of bile acid metabolizing microbes. This study provides a new perspective on the development of COVID-19 therapeutics using primary bile acids.

Electric Cell-Substrate Impedance Sensing (ECIS) as a Platform for Evaluating Barrier-Function Susceptibility and Damage from Pulmonary Atelectrauma

Biophysical insults that either reduce barrier function (COVID-19, smoke inhalation, aspiration, and inflammation) or increase mechanical stress (surfactant dysfunction) make the lung more susceptible to atelectrauma. We investigate the susceptibility and time-dependent disruption of barrier function associated with pulmonary atelectrauma of epithelial cells that occurs in acute respiratory distress syndrome (ARDS) and ventilator-induced lung injury (VILI). This in vitro study was performed using Electric Cell-substrate Impedance Sensing (ECIS) as a noninvasive evaluating technique for repetitive stress stimulus/response on monolayers of the human lung epithelial cell line NCI-H441. Atelectrauma was mimicked through recruitment/derecruitment (RD) of a semi-infinite air bubble to the fluid-occluded micro-channel. We show that a confluent monolayer with a high level of barrier function is nearly impervious to atelectrauma for hundreds of RD events. Nevertheless, barrier function is eventually diminished, and after a critical number of RD insults, the monolayer disintegrates exponentially. Confluent layers with lower initial barrier function are less resilient. These results indicate that the first line of defense from atelectrauma resides with intercellular binding. After disruption, the epithelial layer community protection is diminished and atelectrauma ensues. ECIS may provide a platform for identifying damaging stimuli, ventilation scenarios, or pharmaceuticals that can reduce susceptibility or enhance barrier-function recovery.

Evaluation of the relationship between the disease severity and the level of physical activity in patients followed up with COVID-19 diagnosis

OBJECTIVES

To investigate the relationship between physical activity level and disease severity, anxiety level, sleep quality, and fatigue in patients followed up with COVID-19 diagnosis.

METHODS

This was a cross-sectional study of 111 volunteer patients who were receiving treatment with COVID-19 diagnosis at the Chest Diseases Polyclinic, Sanko University, Sani Konukoğlu Practice and Research Hospital, Gaziantep, Turkey between May 2021 and July 2021 were included in the study and classified clinically and radiologically. They were evaluated on the basis of demographic characteristics, International Physical Activity Questionnaire, Beck Anxiety Inventory, Pittsburgh Sleep Quality Index, and Fatigue Severity Scale.

RESULTS

Approximately 63% of the patients did not have a habit of exercise, while 52.3% of our patients were clinically mild cases, and 33.3% had normal lung tomography. While clinical disease severity was not associated with exercise habits, sleep quality was impaired in clinically severe patients.

CONCLUSION

The results of our study suggested that physical inactivity is common. Anxiety is a frequent symptom in COVID-19 cases and also COVID-19 negatively affects sleep quality.

Inflammasome activation in infected macrophages drives COVID-19 pathology

Severe COVID-19 is characterized by persistent lung inflammation, inflammatory cytokine production, viral RNA and a sustained interferon (IFN) response, all of which are recapitulated and required for pathology in the SARS-CoV-2-infected MISTRG6-hACE2 humanized mouse model of COVID-19, which has a human immune system^1-20. Blocking either viral replication with remdesivir^21-23 or the downstream IFN-stimulated cascade with anti-IFNAR2 antibodies in vivo in the chronic stages of disease attenuates the overactive immune inflammatory response, especially inflammatory macrophages. Here we show that SARS-CoV-2 infection and replication in lung-resident human macrophages is a critical driver of disease. In response to infection mediated by CD16 and ACE2 receptors, human macrophages activate inflammasomes, release interleukin 1 (IL-1) and IL-18, and undergo pyroptosis, thereby contributing to the hyperinflammatory state of the lungs. Inflammasome activation and the accompanying inflammatory response are necessary for lung inflammation, as inhibition of the NLRP3 inflammasome pathway reverses chronic lung pathology. Notably, this blockade of inflammasome activation leads to the release of infectious virus by the infected macrophages. Thus, inflammasomes oppose host infection by SARS-CoV-2 through the production of inflammatory cytokines and suicide by pyroptosis to prevent a productive viral cycle.

[Male reproductive health and COVID-19]

The SARS-CoV-2 pandemic has brought serious economic and social problems worldwide'. Due to its medical consequences, it is of importance to study the mechanisms of the disease and new therapeutic interventions, as well as rehabilitation processes. Despite the fact that the genome of the new coronavirus has been sequenced and studied, clinical and epidemiological data are constantly updated and analyzed, and exact pathogenesis has not yet been understood. At the same time, domestic and foreign studies suggest that the virus is an agent that affects not only the lungs, vascular wall, hemostasis, but also the reproductive system. The aim of the review is to summarize the current knowledge about novel SARS-CoV-2, including its pathophysiology and potential impact on male reproductive function.

Systematic Review of the Common Pathophysiological Mechanisms in COVID-19 and Neurodegeneration: The Role of Bioactive Compounds and Natural Antioxidants

The novel coronavirus (2019-nCoVCOVID-19) belongs to the Beta coronavirus family, which contains MERS-CoV (Middle East respiratory syndrome coronavirus) and SARS-CoV (severe acute respiratory syndrome coronavirus). SARS-CoV-2 activates the innate immune system, thereby activating the inflammatory mechanism, causing the release of inflammatory cytokines. Moreover, it has been suggested that COVID-19 may penetrate the central nervous system, and release inflammatory cytokines in the brains, inducing neuroinflammation and neurodegeneration. Several links connect COVID-19 with Alzheimer’s disease (AD), such as elevated oxidative stress, uncontrolled release of the inflammatory cytokines, and mitochondrial apoptosis. There are severe concerns that excessive immune cell activation in COVID-19 may aggravate the neurodegeneration and amyloid-beta pathology of AD. Here, we have collected the evidence, showing the links between the two diseases. The focus has been made to collect the information on the activation of the inflammation, its contributors, and shared therapeutic targets. Furthermore, we have given future perspectives, research gaps, and overlapping pathological bases of the two diseases. Lastly, we have given the short touch to the drugs that have equally shown rescuing effects against both diseases. Although there is limited information available regarding the exact links between COVID-19 and neuroinflammation, we have insight into the pathological contributors of the diseases. Based on the shared pathological features and therapeutic targets, we hypothesize that the activation of the immune system may induce neurological disorders by triggering oxidative stress and neuroinflammation.

Functional ACE2 deficiency leading to angiotensin imbalance in the pathophysiology of COVID-19

SARS-CoV-2, the virus responsible for COVID-19, uses angiotensin converting enzyme 2 (ACE2) as its primary cell-surface receptor. ACE2 is a key enzyme in the counter-regulatory pathway of the broader renin-angiotensin system (RAS) that has been implicated in a broad array of human pathology. The RAS is composed of two competing pathways that work in opposition to each other: the "conventional" arm involving angiotensin converting enzyme (ACE) generating angiotensin-2 and the more recently identified ACE2 pathway that generates angiotensin (1-7). Following the original SARS pandemic, additional studies suggested that coronaviral binding to ACE2 resulted in downregulation of the membrane-bound enzyme. Given the similarities between the two viruses, many have posited a similar process with SARS-CoV-2. Proponents of this ACE2 deficiency model argue that downregulation of ACE2 limits its enzymatic function, thereby skewing the delicate balance between the two competing arms of the RAS. In this review we critically examine this model. The available data remain incomplete but are consistent with the possibility that the broad multisystem dysfunction of COVID-19 is due in large part to functional ACE2 deficiency leading to angiotensin imbalance with consequent immune dysregulation and endothelial cell dysfunction.

Investigating the impact of SARS-CoV-2 infection on basic semen parameters and in vitro fertilization/intracytoplasmic sperm injection outcomes: a retrospective cohort study

BACKGROUND

This study aimed to evaluate the influences of SARS-CoV-2 infection on semen parameters and investigate the impact of the infection on in vitro fertilization (IVF) outcomes.

METHODS

This retrospective study enrolled couples undergoing IVF cycles between May 2020 and February 2021 at Tongji Hospital, Wuhan. Baseline characteristics were matched using propensity score matching. Participants were categorized into an unexposed group (SARS-COV-2 negative) and exposed group (SARS-COV-2 positive) based on a history of SARS-CoV-2 infection, and the populations were 148 and 50 after matching, respectively. IVF data were compared between the matched cohorts. Moreover, semen parameters were compared before and after infection among the infected males. The main measures were semen parameters and IVF outcomes, including laboratory and clinical outcomes.

RESULTS

Generally, the concentration and motility of sperm did not significantly differ before and after infection. Infected males seemed to have fewer sperm with normal morphology, while all values were above the limits. Notably, the blastocyst formation rate and available blastocyst rate in the exposed group were lower than those in the control group, despite similar mature oocytes rates, normal fertilization rates, cleavage rates, and high-quality embryo rates. Moreover, no significant differences were exhibited between the matched cohorts regarding the implantation rate, biochemical pregnancy rate, clinical pregnancy rate, or early miscarriage rate.

CONCLUSIONS

The results of this retrospective cohort study suggested that the semen quality and the chance of pregnancy in terms of IVF outcomes were comparable between the males with a history of SARS-CoV-2 infection and controls, although a decreased blastocyst formation rate and available blastocyst rate was observed in the exposed group, which needs to be reinforced by a multicenter long-term investigation with a larger sample size.

Biological evaluation of a mechanical ventilator that operates by controlling an automated manual resuscitator. A descriptive study in swine

The Covid-19 outbreak challenged health systems around the world to design and implement cost-effective devices produced locally to meet the increased demand of mechanical ventilators worldwide. This study evaluates the physiological responses of healthy swine maintained under volume- or pressure-controlled mechanical ventilation by a mechanical ventilator implemented to bring life-support by automating a resuscitation bag and closely controlling ventilatory parameters. Physiological parameters were monitored in eight sedated animals (t₀) prior to inducing deep anaesthesia, and during the next six hours of mechanical ventilation (t₁-₇). Hemodynamic conditions were monitored periodically using a portable gas analyser machine (i.e. BEecf, carbonate, SaO₂, lactate, pH, PaO₂, PaCO₂) and a capnometer (i.e. ETCO₂). Electrocardiogram, echocardiography and lung ultrasonography were performed to detect in vivo alterations in these vital organs and pathological findings from necropsy were reported. The mechanical ventilator properly controlled physiological levels of blood biochemistry such as oxygenation parameters (PaO₂, PaCO₂, SaO₂, ETCO₂), acid-base equilibrium (pH, carbonate, BEecf), and perfusion of tissues (lactate levels). In addition, histopathological analysis showed no evidence of acute tissue damage in lung, heart, liver, kidney, or brain. All animals were able to breathe spontaneously after undergoing mechanical ventilation. These preclinical data, supports the biological safety of the medical device to move forward to further evaluation in clinical studies.

Sexual dimorphism in COVID-19: potential clinical and public health implications

Current evidence suggests that severity and mortality of COVID-19 is higher in men than in women, whereas women might be at increased risk of COVID-19 reinfection and development of long COVID. Differences between sexes have been observed in other infectious diseases and in the response to vaccines. Sex-specific expression patterns of proteins mediating virus binding and entry, and divergent reactions of the immune and endocrine system, in particular the hypothalamic-pituitary-adrenal axis, in response to acute stress might explain the higher severity of COVID-19 in men. In this Personal View, we discuss how sex hormones, comorbidities, and the sex chromosome complement influence these mechanisms in the context of COVID-19. Due to its role in the severity and progression of SARS-CoV-2 infections, we argue that sexual dimorphism has potential implications for disease treatment, public health measures, and follow-up of patients predisposed to the development of long COVID. We suggest that sex differences could be considered in future pandemic surveillance and treatment of patients with COVID-19 to help to achieve better disease stratification and improved outcomes.

Establishment of Human Pluripotent Stem Cell-Derived Skin Organoids Enabled Pathophysiological Model of SARS-CoV-2 Infection

Coronavirus disease 2019 (COVID-19) patients with impact on skin and hair loss are reported. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is detected in the skin of some patients; however, the detailed pathological features of skin tissues from patients infected with SARS-CoV-2 at a molecular level are limited. Especially, the ability of SARS-CoV-2 to infect skin cells and impact their function is not well understood. A proteome map of COVID-19 skin is established here and the susceptibility of human-induced pluripotent stem cell (hiPSC)-derived skin organoids with hair follicles and nervous system is investigated, to SARS-CoV-2 infection. It is shown that KRT17+ hair follicles can be infected by SARS-CoV-2 and are associated with the impaired development of hair follicles and epidermis. Different types of nervous system cells are also found to be infected, which can lead to neuron death. Findings from the present work provide evidence for the association between COVID-19 and hair loss. hiPSC-derived skin organoids are also presented as an experimental model which can be used to investigate the susceptibility of skin cells to SARS-CoV-2 infection and can help identify various pathological mechanisms and drug screening strategies.

Feature selection reveal peripheral blood parameter's changes between COVID-19 infections patients from Brazil and Ecuador

The investigation of conventional complete blood-count (CBC) data for classifying the SARS-CoV-2 infection status became a topic of interest, particularly as a complementary laboratory tool in developing and third-world countries that financially struggled to test their population. Although hematological parameters in COVID-19-affected individuals from Asian and USA populations are available, there are no descriptions of comparative analyses of CBC findings between COVID-19 positive and negative cases from Latin American countries. In this sense, machine learning techniques have been employed to examine CBC data and aid in screening patients suspected of SARS-CoV-2 infection. In this work, we used machine learning to compare CBC data between two highly genetically distinguished Latin American countries: Brazil and Ecuador. We notice a clear distribution pattern of positive and negative cases between the two countries. Interestingly, almost all red blood cell count parameters were divergent. For males, neutrophils and lymphocytes are distinct between Brazil and Ecuador, while eosinophils are distinguished for females. Finally, neutrophils, lymphocytes, and monocytes displayed a particular distribution for both genders. Therefore, our findings demonstrate that the same set of CBC features relevant to one population is unlikely to apply to another. This is the first study to compare CBC data from two genetically distinct Latin American countries.

Alveolar, Endothelial, and Organ Injury Marker Dynamics in Severe COVID-19

Rationale: Alveolar and endothelial injury may be differentially associated with coronavirus disease (COVID-19) severity over time. Objectives: To describe alveolar and endothelial injury dynamics and associations with COVID-19 severity, cardiorenovascular injury, and outcomes. Methods: This single-center observational study enrolled patients with COVID-19 requiring respiratory support at emergency department presentation. More than 40 markers of alveolar (including receptor for advanced glycation endproducts [RAGE]), endothelial (including angiopoietin-2), and cardiorenovascular injury (including renin, kidney injury molecule-1, and troponin-I) were serially compared between invasively and spontaneously ventilated patients using mixed-effects repeated-measures models. Ventilatory ratios were calculated for intubated patients. Associations of biomarkers with modified World Health Organization scale at Day 28 were determined with multivariable proportional-odds regression. Measurements and Main Results: Of 225 patients, 74 (33%) received invasive ventilation at Day 0. RAGE was 1.80-fold higher in invasive ventilation patients at Day 0 (95% confidence interval [CI], 1.50-2.17) versus spontaneous ventilation, but decreased over time in all patients. Changes in alveolar markers did not correlate with changes in endothelial, cardiac, or renal injury markers. In contrast, endothelial markers were similar to lower at Day 0 for invasive ventilation versus spontaneous ventilation, but then increased over time only among intubated patients. In intubated patients, angiopoietin-2 was similar (fold difference, 1.02; 95% CI, 0.89-1.17) to nonintubated patients at Day 0 but 1.80-fold higher (95% CI, 1.56-2.06) at Day 3; cardiorenovascular injury markers showed similar patterns. Endothelial markers were not consistently associated with ventilatory ratios. Endothelial markers were more often significantly associated with 28-day outcomes than alveolar markers. Conclusions: Alveolar injury markers increase early. Endothelial injury markers increase later and are associated with cardiorenovascular injury and 28-day outcome. Alveolar and endothelial injury likely contribute at different times to disease progression in severe COVID-19.

Associations Between Symptoms, Donor Characteristics and IgG Antibody Response in 2082 COVID-19 Convalescent Plasma Donors

Many studies already reported on the association between patient characteristics on the severity of COVID-19 disease outcome, but the relation with SARS-CoV-2 antibody levels is less clear. To investigate this in more detail, we performed a retrospective observational study in which we used the IgG antibody response from 11,118 longitudinal antibody measurements of 2,082 unique COVID convalescent plasma donors. COVID-19 symptoms and donor characteristics were obtained by a questionnaire. Antibody responses were modelled using a linear mixed-effects model. Our study confirms that the SARS-CoV-2 antibody response is associated with patient characteristics like body mass index and age. Antibody decay was faster in male than in female donors (average half-life of 62 versus 72 days). Most interestingly, we also found that three symptoms (headache, anosmia, nasal cold) were associated with lower peak IgG, while six other symptoms (dry cough, fatigue, diarrhoea, fever, dyspnoea, muscle weakness) were associated with higher IgG concentrations.

High-Flow Nasal Oxygen for Severe Hypoxemia: Oxygenation Response and Outcome in Patients with COVID-19

Rationale: The "Berlin definition" of acute respiratory distress syndrome (ARDS) does not allow inclusion of patients receiving high-flow nasal oxygen (HFNO). However, several articles have proposed that criteria for defining ARDS should be broadened to allow inclusion of patients receiving HFNO. Objectives: To compare the proportion of patients fulfilling ARDS criteria during HFNO and soon after intubation, and 28-day mortality between patients treated exclusively with HFNO and patients transitioned from HFNO to invasive mechanical ventilation (IMV). Methods: From previously published studies, we analyzed patients with coronavirus disease (COVID-19) who had PaO2/FiO2 of ⩽300 while treated with ⩾40 L/min HFNO, or noninvasive ventilation (NIV) with positive end-expiratory pressure of ⩾5 cm H2O (comparator). In patients transitioned from HFNO/NIV to invasive mechanical ventilation (IMV), we compared ARDS severity during HFNO/NIV and soon after IMV. We compared 28-day mortality in patients treated exclusively with HFNO/NIV versus patients transitioned to IMV. Measurements and Main Results: We analyzed 184 and 131 patients receiving HFNO or NIV, respectively. A total of 112 HFNO and 69 NIV patients transitioned to IMV. Of those, 104 (92.9%) patients on HFNO and 66 (95.7%) on NIV continued to have PaO2/FiO2 ⩽300 under IMV. Twenty-eight-day mortality in patients who remained on HFNO was 4.2% (3/72), whereas in patients transitioned from HFNO to IMV, it was 28.6% (32/112) (P < 0.001). Twenty-eight-day mortality in patients who remained on NIV was 1.6% (1/62), whereas in patients who transitioned from NIV to IMV, it was 44.9% (31/69) (P < 0.001). Overall mortality was 19.0% (35/184) and 24.4% (32/131) for HFNO and NIV, respectively (P = 0.2479). Conclusions: Broadening the ARDS definition to include patients on HFNO with PaO2/FiO2 ⩽300 may identify patients at earlier stages of disease but with lower mortality.

Self-reported symptom study of COVID-19 chemosensory dysfunction in Malaysia

Alterations in the three chemosensory modalities-smell, taste, and chemesthesis-have been implicated in Coronavirus Disease 2019 (COVID-19), yet emerging data suggest a wide geographic and ethnic variation in the prevalence of these symptoms. Studies on chemosensory disorders in COVID-19 have predominantly focused on Caucasian populations whereas Asians remain understudied. We conducted a nationwide, multicentre cross-sectional study using an online questionnaire on a cohort of RT-PCR-confirmed adult COVID-19 patients in Malaysia between 6 June and 30 November 2020. The aim of our study was to investigate their presenting symptoms and assess their chemosensory function using self-ratings of perceived smell, taste, chemesthesis, and nasal blockage. In this cohort of 498 patients, 41.4% reported smell and/or taste loss when diagnosed with COVID-19, which was the commonest symptom. Blocked nose, loss of appetite, and gastrointestinal disturbances were independent predictors of smell and/or taste loss on multivariate analysis. Self-ratings of chemosensory function revealed a reduction in smell, taste, and chemesthesis across the entire cohort of patients that was more profound among those reporting smell and/or taste loss as their presenting symptom. Perceived nasal obstruction accounted for only a small proportion of changes in smell and taste, but not for chemesthesis, supporting viral disruption of sensorineural mechanisms as the dominant aetiology of chemosensory dysfunction. Our study suggests that chemosensory dysfunction in COVID-19 is more widespread than previously reported among Asians and may be related to the infectivity of viral strains.Study Registration: NMRR-20-934-54803 and NCT04390165.

A population-based cohort study of obesity, ethnicity and COVID-19 mortality in 12.6 million adults in England

Obesity and ethnicity are known risk factors for COVID-19 outcomes, but their combination has not been extensively examined. We investigate the association between body mass index (BMI) and COVID-19 mortality across different ethnic groups using linked national Census, electronic health records and mortality data for adults in England from the start of pandemic (January 2020) to December 2020. There were 30,067 (0.27%), 1,208 (0.29%), 1,831 (0.29%), 845 (0.18%) COVID-19 deaths in white, Black, South Asian and other ethnic minority groups, respectively. Here we show that BMI was more strongly associated with COVID-19 mortality in ethnic minority groups, resulting in an ethnic risk of COVID-19 mortality that was dependant on BMI. The estimated risk of COVID-19 mortality at a BMI of 40 kg/m² in white ethnicities was equivalent to the risk observed at a BMI of 30.1 kg/m², 27.0 kg/m², and 32.2 kg/m² in Black, South Asian and other ethnic minority groups, respectively.

Focal Peripheral Neuropathies Observed in Patients Diagnosed With COVID-19: A Case Series

ABSTRACT

A growing number of studies have documented a wide variety of neurological manifestations associated with the novel SARS-CoV-2 (COVID-19). Of the available literature, cranial neuropathies and central nervous system disorders, such as encephalopathy and ischemic strokes, remain the predominant discussion. Limited investigations exist examining peripheral neuropathies of those with COVID-19. This case series discusses eight patients who tested positive for COVID-19 and presented with localized weakness after a prolonged course of mechanical ventilation (>21 days). We retrospectively reviewed all patients' charts who received electrodiagnostic evaluation between March and November 2020 in the outpatient clinic or in the acute care hospital at the JFK Medical Center/JFK Johnson Rehabilitation Institute and Saint Peter's University Hospital of New Jersey. A total of eight COVID-19-positive patients were identified to have a clinical presentation of localized weakness after a prolonged course of mechanical ventilation. All patients were subsequently found to have a focal peripheral neuropathy of varying severity that was confirmed by electrodiagnostic testing. Patient demographics, clinical, and electrodiagnostic findings were documented. The findings of local weakness and focal peripheral neuropathies after diagnosis of COVID-19 raise significant questions regarding underlying pathophysiology and overall prognosis associated with COVID-19.

Vitamin D as a Protective Factor in COVID-19 Infection in Elderly Schizophrenia and Dementia Inpatients: A Case Series

BACKGROUND

Risk factors for severe coronavirus disease-2019 (COVID-19) infection include old age, chronic illness, and neurological conditions. In contrast, high vitamin D levels are known to augment immune activity and to reduce the severity of viral infections. Recently, a possible association between the likelihood of COVID-19 infection, COVID-19 severity, and vitamin D blood levels was reported.

OBJECTIVES

To assess the possible association between vitamin D long-term supplementation and COVID-19 symptomatic severity and complications of COVID-19 infection in elderly psychiatric inpatients, a high at-risk group.

METHODS

We conducted a retrospective case series study. Data of 14 elderly COVID-19 positive inpatients, presenting with dementia or schizophrenia and other medical conditions were extracted from medical records. All patients maintained a 800 IU daily dose of vitamin D prior to the infection.

RESULTS

Most of the inpatients were asymptomatic or presented very few symptoms. No need for intensive care unit intervention or deaths were reported. Cognitive functioning of the patients remained unchanged.

CONCLUSIONS

Pre-existing vitamin D supplementation may reinforce immunity and reduce COVID-19 severity in elderly psychiatric inpatients.

Prevalence of Select New Symptoms and Conditions Among Persons Aged Younger Than 20 Years and 20 Years or Older at 31 to 150 Days After Testing Positive or Negative for SARS-CoV-2

IMPORTANCE

New symptoms and conditions can develop following SARS-CoV-2 infection. Whether they occur more frequently among persons with SARS-CoV-2 infection compared with those without is unclear.

OBJECTIVE

To compare the prevalence of new diagnoses of select symptoms and conditions between 31 and 150 days after testing among persons who tested positive vs negative for SARS-CoV-2.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study analyzed aggregated electronic health record data from 40 health care systems, including 338 024 persons younger than 20 years and 1 790 886 persons aged 20 years or older who were tested for SARS-CoV-2 during March to December 2020 and who had medical encounters between 31 and 150 days after testing.

MAIN OUTCOMES AND MEASURES

International Statistical Classification of Diseases, Tenth Revision, Clinical Modification codes were used to capture new symptoms and conditions that were recorded 31 to 150 days after a SARS-CoV-2 test but absent in the 18 months to 7 days prior to testing. The prevalence of new symptoms and conditions was compared between persons with positive and negative SARS-CoV-2 tests stratified by age (20 years or older and young than 20 years) and care setting (nonhospitalized, hospitalized, or hospitalized and ventilated).

RESULTS

A total of 168 701 persons aged 20 years or older and 26 665 younger than 20 years tested positive for SARS-CoV-2, and 1 622 185 persons aged 20 years or older and 311 359 younger than 20 years tested negative. Shortness of breath was more common among persons with a positive vs negative test result among hospitalized patients (≥20 years: prevalence ratio [PR], 1.89 [99% CI, 1.79-2.01]; <20 years: PR, 1.72 [99% CI, 1.17-2.51]). Shortness of breath was also more common among nonhospitalized patients aged 20 years or older with a positive vs negative test result (PR, 1.09 [99% CI, 1.05-1.13]). Among hospitalized persons aged 20 years or older, the prevalence of new fatigue (PR, 1.35 [99% CI, 1.27-1.44]) and type 2 diabetes (PR, 2.03 [99% CI, 1.87-2.19]) was higher among those with a positive vs a negative test result. Among hospitalized persons younger than 20 years, the prevalence of type 2 diabetes (PR, 2.14 [99% CI, 1.13-4.06]) was higher among those with a positive vs a negative test result; however, the prevalence difference was less than 1%.

CONCLUSIONS AND RELEVANCE

In this cohort study, among persons hospitalized after a positive SARS-CoV-2 test result, diagnoses of certain symptoms and conditions were higher than among those with a negative test result. Health care professionals should be aware of symptoms and conditions that may develop after SARS-CoV-2 infection, particularly among those hospitalized after diagnosis.

Classification and occurrence of an abnormal breathing pattern during cardiopulmonary exercise testing in subjects with persistent symptoms following COVID-19 disease

Reduced exercise capacity and several limiting symptoms during exercise have been reported following severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. From clinical observations, we hypothesized that an abnormal breathing pattern (BrP) during exercise may be common in these patients and related to reduced exercise capacity. We aimed to (a) evaluate a method to classify the BrP as normal/abnormal or borderline in terms of inter-rater agreement; (b) determine the occurrence of an abnormal BrP in patients with post-COVID; and (c) compare characteristics of post-COVID patients with normal and abnormal BrP. In a retrospective, cross-sectional study of patients referred for CPET due to post-COVID April 2020-April 2021, we selected subjects without a history of intensive care and with available medical records. Three raters independently categorized patients' BrP as normal, abnormal, or borderline, using four traditional CPET plots (respiratory exchange ratio, tidal volume over ventilation, ventilatory equivalent for oxygen, and ventilation over time). Out of 20 patients (11 male), 10 were categorized as having a normal, 7 an abnormal, and three a borderline BrP. Inter-rater agreement was good (Fleiss' kappa: 0.66 [0.66-0.67]). Subjects with an abnormal BrP had lower peak ventilation, lower exercise capacity, similar ventilatory efficiency and a similar level of dyspnea at peak exercise, as did subjects with a normal BrP. Patients' BrP was possible to classify with good agreement between observers. A third of patients had an abnormal BrP, associated with lower exercise capacity, which could possibly explain exercise related symptoms in some patients with post-COVID syndrome.

Covid-19 and Liver Injury: Role of Inflammatory Endotheliopathy, Platelet Dysfunction, and Thrombosis

Liver injury, characterized predominantly by elevated aspartate aminotransferase and alanine aminotransferase, is a common feature of coronavirus disease 2019 (COVID-19) symptoms caused by severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2). Additionally, SARS-CoV-2 infection is associated with acute-on-chronic liver failure in patients with cirrhosis and has a notably elevated mortality in patients with alcohol-related liver disease compared to other etiologies. Direct viral infection of the liver with SARS-CoV-2 remains controversial, and alternative pathophysiologic explanations for its hepatic effects are an area of active investigation. In this review, we discuss the effects of SARS-CoV-2 and the inflammatory environment it creates on endothelial cells and platelets more generally and then with a hepatic focus. In doing this, we present vascular inflammation and thrombosis as a potential mechanism of liver injury and liver-related complications in COVID-19.

Nitric oxide-mediated cutaneous microvascular function is not altered in young adults following mild-to-moderate SARS CoV-2 infection

Vascular dysfunction has been reported in adults who have recovered from COVID-19. To date, no studies have investigated the underlying mechanisms of persistent COVID-19-associated vascular dysfunction. Our purpose was to quantify nitric oxide (NO)-mediated vasodilation in healthy adults who have recovered from SARS-CoV-2 infection. We hypothesized that COVID-19-recovered adults would have impaired NO-mediated vasodilation compared with adults who have not had COVID-19. In methods, we performed a cross-sectional study including 10 (5 men/5 women, 24 ± 4 yr) healthy control (HC) adults who were unvaccinated for COVID-19, 11 (4 men/7 women, 25 ± 6 yr) healthy vaccinated (HV) adults, and 12 (5 men/7 women, 22 ± 3 yr) post-COVID-19 (PC, 19 ± 14 wk) adults. COVID-19 symptoms severity (survey) was assessed. A standardized 39°C local heating protocol was used to assess NO-dependent vasodilation via perfusion (intradermal microdialysis) of 15 mM NG-nitro-l-arginine methyl ester during the plateau of the heating response. Red blood cell flux was measured (laser-Doppler flowmetry) and cutaneous vascular conductance (CVC = flux/mmHg) was expressed as a percentage of maximum (28 mM sodium nitroprusside + 43°C). In results, the local heating plateau (HC: 61 ± 20%, HV: 60 ± 19%, PC: 67 ± 19%, P = 0.80) and NO-dependent vasodilation (HC: 77 ± 9%, HV: 71 ± 7%, PC: 70 ± 10%, P = 0.36) were not different among groups. Neither symptom severity (25 ± 12 AU) nor time since diagnosis correlated with the NO-dependent vasodilation (r = 0.46, P = 0.13; r = 0.41, P = 0.19, respectively). In conclusion, healthy adults who have had mild-to-moderate COVID-19 do not have altered NO-mediated cutaneous microvascular function.NEW & NOTEWORTHY Healthy young adults who have had mild-to-moderate COVID-19 do not display alterations in nitric oxide-mediated cutaneous microvascular function. In addition, healthy young adults who have COVID-19 antibodies from the COVID-19 vaccinations do not display alterations in nitric oxide-mediated cutaneous microvascular function.

Pathological sequelae of long-haul COVID

The world continues to contend with successive waves of coronavirus disease 2019 (COVID-19), fueled by the emergence of viral variants. At the same time, persistent, prolonged and often debilitating sequelae are increasingly recognized in convalescent individuals, named 'post-COVID-19 syndrome' or 'long-haul COVID'. Clinical symptomatology includes fatigue, malaise, dyspnea, defects in memory and concentration and a variety of neuropsychiatric syndromes as the major manifestations, and several organ systems can be involved. The underlying pathophysiological mechanisms are poorly understood at present. This Review details organ-specific sequelae of post-COVID-19 syndromes and examines the underlying pathophysiological mechanisms available so far, elaborating on persistent inflammation, induced autoimmunity and putative viral reservoirs. Finally, we propose diagnostic strategies to better understand this heterogeneous disorder that continues to afflict millions of people worldwide.

Metabolomics study of COVID-19 patients in four different clinical stages

SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) is the coronavirus strain causing the respiratory pandemic COVID-19 (coronavirus disease 2019). To understand the pathobiology of SARS-CoV-2 in humans it is necessary to unravel the metabolic changes that are produced in the individuals once the infection has taken place. The goal of this work is to provide new information about the altered biomolecule profile and with that the altered biological pathways of patients in different clinical situations due to SARS-CoV-2 infection. This is done via metabolomics using HPLC-QTOF-MS analysis of plasma samples at COVID-diagnose from a total of 145 adult patients, divided into different clinical stages based on their subsequent clinical outcome (25 negative controls (non-COVID); 28 positive patients with asymptomatic disease not requiring hospitalization; 27 positive patients with mild disease defined by a total time in hospital lower than 10 days; 36 positive patients with severe disease defined by a total time in hospital over 20 days and/or admission at the ICU; and 29 positive patients with fatal outcome or deceased). Moreover, follow up samples between 2 and 3 months after hospital discharge were also obtained from the hospitalized patients with mild prognosis. The final goal of this work is to provide biomarkers that can help to better understand how the COVID-19 illness evolves and to predict how a patient could progress based on the metabolites profile of plasma obtained at an early stage of the infection. In the present work, several metabolites were found as potential biomarkers to distinguish between the end-stage and the early-stage (or non-COVID) disease groups. These metabolites are mainly involved in the metabolism of carnitines, ketone bodies, fatty acids, lysophosphatidylcholines/phosphatidylcholines, tryptophan, bile acids and purines, but also omeprazole. In addition, the levels of several of these metabolites decreased to "normal" values at hospital discharge, suggesting some of them as early prognosis biomarkers in COVID-19 at diagnose.

Early assessment of the clinical severity of the SARS-CoV-2 omicron variant in South Africa: a data linkage study

BACKGROUND

The SARS-CoV-2 omicron variant of concern was identified in South Africa in November, 2021, and was associated with an increase in COVID-19 cases. We aimed to assess the clinical severity of infections with the omicron variant using S gene target failure (SGTF) on the Thermo Fisher Scientific TaqPath COVID-19 PCR test as a proxy.

METHODS

We did data linkages for national, South African COVID-19 case data, SARS-CoV-2 laboratory test data, SARS-CoV-2 genome data, and COVID-19 hospital admissions data. For individuals diagnosed with COVID-19 via TaqPath PCR tests, infections were designated as either SGTF or non-SGTF. The delta variant was identified by genome sequencing. Using multivariable logistic regression models, we assessed disease severity and hospitalisations by comparing individuals with SGTF versus non-SGTF infections diagnosed between Oct 1 and Nov 30, 2021, and we further assessed disease severity by comparing SGTF-infected individuals diagnosed between Oct 1 and Nov 30, 2021, with delta variant-infected individuals diagnosed between April 1 and Nov 9, 2021.

FINDINGS

From Oct 1 (week 39), 2021, to Dec 6 (week 49), 2021, 161 328 cases of COVID-19 were reported in South Africa. 38 282 people were diagnosed via TaqPath PCR tests and 29 721 SGTF infections and 1412 non-SGTF infections were identified. The proportion of SGTF infections increased from two (3·2%) of 63 in week 39 to 21 978 (97·9%) of 22 455 in week 48. After controlling for factors associated with hospitalisation, individuals with SGTF infections had significantly lower odds of admission than did those with non-SGTF infections (256 [2·4%] of 10 547 vs 121 [12·8%] of 948; adjusted odds ratio [aOR] 0·2, 95% CI 0·1-0·3). After controlling for factors associated with disease severity, the odds of severe disease were similar between hospitalised individuals with SGTF versus non-SGTF infections (42 [21%] of 204 vs 45 [40%] of 113; aOR 0·7, 95% CI 0·3-1·4). Compared with individuals with earlier delta variant infections, SGTF-infected individuals had a significantly lower odds of severe disease (496 [62·5%] of 793 vs 57 [23·4%] of 244; aOR 0·3, 95% CI 0·2-0·5), after controlling for factors associated with disease severity.

INTERPRETATION

Our early analyses suggest a significantly reduced odds of hospitalisation among individuals with SGTF versus non-SGTF infections diagnosed during the same time period. SGTF-infected individuals had a significantly reduced odds of severe disease compared with individuals infected earlier with the delta variant. Some of this reduced severity is probably a result of previous immunity.

FUNDING

The South African Medical Research Council, the South African National Department of Health, US Centers for Disease Control and Prevention, the African Society of Laboratory Medicine, Africa Centers for Disease Control and Prevention, the Bill & Melinda Gates Foundation, the Wellcome Trust, and the Fleming Fund.