Tag: Nath

Post-exertional malaise in Long COVID: subjective reporting versus objective assessment

Abstract:

Background: Post-exertional malaise (PEM) is a central feature of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and has emerged as a prominent feature of Long COVID. The optimal clinical approach to PEM is inconclusive, and studies of the impact of exercise have yielded contradictory results.

Objective: The objective of this study was to examine PEM in Long COVID by assessing the prevalence of self-reported PEM across study cohorts and symptom responses of Long COVID patients to a standardized exercise stressor. Secondarily, Long COVID symptom responses to exercise were compared to those of ME/CFS and healthy volunteers.

Methods: Data from three registered clinical trials comprised four cohorts in this study: Long COVID Questionnaire Cohort (QC; n = 244), Long COVID Exercise Cohort (EC; n = 34), ME/CFS cohort (n = 9), and healthy volunteers (HV; n = 9). All cohorts completed questionnaires related to physical function, fatigue, and/or PEM symptoms. EC also performed a standardized exercise test (cardiopulmonary exercise test, CPET), and the PEM response to CPET was assessed using visual analog scales and qualitative interviews (QIs) administered serially over 72 h. EC PEM measures were compared to ME/CFS and HV cohorts. A secondary analysis of QI explored positive responses to CPET among EC, ME/CFS and HV.

Results: Self-reported PEM was 67% in QC and estimated at 27% in EC. Only 2 of 34 EC patients (5.9%) were observed to develop PEM after a CPET. In addition, PEM responses after CPET in Long COVID were not as severe and prolonged as those assessed in ME/CFS. Twenty-two of 34 EC patients (64.7%) expressed at least one of 7 positive themes after the CPET.

Conclusion: Self-report of PEM is common in Long COVID. However, observable PEM following an exercise stressor was not frequent in this small cohort. When present, PEM descriptions during QI were less severe in Long COVID than in ME/CFS. Positive responses after an exercise stressor were common in Long COVID. Exercise testing to determine the presence of PEM may have utility for guiding clinical management of Long COVID.

Source: Stussman B, Camarillo N, McCrossin G, Stockman M, Norato G, Vetter CS, Ferrufino A, Adedamola A, Grayson N, Nath A, Chan L, Walitt B, Chin LMK. Post-exertional malaise in Long COVID: subjective reporting versus objective assessment. Front Neurol. 2025 Apr 23;16:1534352. doi: 10.3389/fneur.2025.1534352. PMID: 40337174; PMCID: PMC12055772. https://pmc.ncbi.nlm.nih.gov/articles/PMC12055772/ (Full text)

NIH study offers new clues into the causes of post-infectious ME/CFS

Press Release:

In a detailed clinical study, researchers at the National Institutes of Health have found differences in the brains and immune systems of people with post-infectious myalgic encephalomyelitis/chronic fatigue syndrome (PI-ME/CFS). They also found distinct differences between men and women with the disease. The findings were published in Nature Communications.

“People with ME/CFS have very real and disabling symptoms, but uncovering their biological basis has been extremely difficult,” said Walter Koroshetz, M.D., director of NIH’s National Institute of Neurological Disorders and Stroke (NINDS). “This in-depth study of a small group of people found a number of factors that likely contribute to their ME/CFS. Now researchers can test whether these findings apply to a larger patient group and move towards identifying treatments that target core drivers of the disease.”

A team of multidisciplinary researchers discovered how feelings of fatigue are processed in the brains of people with ME/CFS. Results from functional magnetic resonance imaging (fMRI) brain scans showed that people with ME/CFS had lower activity in a brain region called the temporal-parietal junction (TPJ), which may cause fatigue by disrupting the way the brain decides how to exert effort.

They also analyzed spinal fluid collected from participants and found abnormally low levels of catecholamines and other molecules that help regulate the nervous system in people with ME/CFS compared to healthy controls. Reduced levels of certain catecholamines were associated with worse motor performance, effort-related behaviors, and cognitive symptoms. These findings, for the first time, suggest a link between specific abnormalities or imbalances in the brain and ME/CFS.

“We think that the immune activation is affecting the brain in various ways, causing biochemical changes and downstream effects like motor, autonomic, and cardiorespiratory dysfunction,” said Avindra Nath, M.D., clinical director at NINDS and senior author of the study.

Immune testing revealed that the ME/CFS group had higher levels of naive B cells and lower levels of switched memory B cells—cells that help the immune system fight off pathogens—in blood compared to healthy controls. Naive B cells are always present in the body and activate when they encounter any given antigen, a foreign substance that triggers the immune system. Memory B cells respond to a specific antigen and help maintain adaptive or acquired immunity. More studies are needed to determine how these immune markers relate to brain dysfunction and fatigue in ME/CFS.

To study fatigue, Dr. Nath and his team asked participants to make risk-based decisions about exerting physical effort. This allowed them to assess the cognitive aspects of fatigue, or how an individual decides how much effort to exert when given a choice. People with ME/CFS had difficulties with the effort choice task and with sustaining effort. The motor cortex, a brain region in charge of telling the body to move, also remained abnormally active during fatiguing tasks. There were no signs of muscle fatigue. This suggests that fatigue in ME/CFS could be caused by a dysfunction of brain regions that drive the motor cortex, such as the TPJ.

“We may have identified a physiological focal point for fatigue in this population,” said Brian Walitt, M.D., M.P.H., associate research physician at NINDS and first author of the study. “Rather than physical exhaustion or a lack of motivation, fatigue may arise from a mismatch between what someone thinks they can achieve and what their bodies perform.”

Deeper analyses revealed differences between men and women in gene expression patterns, immune cell populations, and metabolic markers. Males had altered T cell activation, as well as markers of innate immunity, while females had abnormal B cell and white blood cell growth patterns. Men and women also had distinct markers of inflammation.

“Men and women were quite divergent in their data, and that tells you that ME/CFS is not one-size-fits-all,” said Dr. Nath. “Considering male and female immune differences in ME/CFS, the results may open up new avenues of research that could provide insight into other infection-associated chronic diseases.”

The study, which was conducted at the NIH Clinical Center, took a comprehensive look at ME/CFS that developed after a viral or bacterial infection. The team used state-of-the-art techniques to examine 17 people with PI-ME/CFS who had been sick for less than five years and 21 healthy controls. Participants were screened and medically evaluated for ME/CFS over several days and underwent extensive tests, including clinical exams, fMRI brain imaging, physical and cognitive performance tests, autonomic function tests, skin and muscle biopsies, and advanced analyses of blood and spinal fluid. Participants also spent time in metabolic chambers where, under controlled conditions, their diet, energy consumption, metabolism, sleep patterns, and gut microbiome were evaluated. During a second visit, they completed a cardiopulmonary exercise test to measure the body’s response to exercise.

Many studies have identified immune, microbiome, and other abnormalities in ME/CFS, but the results tend to be inconsistent and exactly how these markers relate to or cause fatigue and other symptoms is unknown. By using a rigorous phenotyping approach to pull out meaningful differences, this study helps validate prior results and may identify new ways to target the brain or immune system therapeutically.

The highly collaborative project involved 75 investigators across 15 institutes and centers in the NIH Intramural Research Program, and at national and international institutions. Dr. Nath and his colleagues plan to publish additional findings from the data that was collected during this study.

The study was supported in part by the Intramural Research Program at the NIH.

Article:

Walitt, B., et al. “Deep phenotyping of Post-infectious Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.” Nature Communications. February 21, 2024. DOI: 10.1038/s41467-024-45107-3

NINDS is the nation’s leading funder of research on the brain and nervous system. The mission of NINDS is to seek fundamental knowledge about the brain and nervous system and to use that knowledge to reduce the burden of neurological disease.

About the National Institutes of Health (NIH): NIH, the nation’s medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit the NIH website.

Mixed methods system for the assessment of post-exertional malaise in myalgic encephalomyelitis/chronic fatigue syndrome: an exploratory study

Abstract:

Background A central feature of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is post-exertional malaise (PEM), which is an acute worsening of symptoms after a physical, emotional and/or mental exertion. Dynamic measures of PEM have historically included scaled questionnaires, which have not been validated in ME/CFS. To enhance our understanding of PEM and how best to measure it, we conducted semistructured qualitative interviews (QIs) at the same intervals as visual analogue scale (VAS) measures after a cardiopulmonary exercise test (CPET).

Methods Ten ME/CFS and nine healthy volunteers participated in a CPET. For each volunteer, PEM symptom VAS (12 symptoms) and semistructured QIs were administered at six timepoints over 72 hours before and after a single CPET. QI data were used to plot the severity of PEM at each time point and identify the self-described most bothersome symptom for each ME/CFS volunteer. Performance of QI and VAS data was compared with each other using Spearman correlations.

Results Each ME/CFS volunteer had a unique PEM experience, with differences noted in the onset, severity, trajectory over time and most bothersome symptom. No healthy volunteers experienced PEM. QI and VAS fatigue data corresponded well an hour prior to exercise (pre-CPET, r=0.7) but poorly at peak PEM (r=0.28) and with the change from pre-CPET to peak (r=0.20). When the most bothersome symptom identified from QIs was used, these correlations improved (r=0.0.77, 0.42. and 0.54, respectively) and reduced the observed VAS scale ceiling effects.

Conclusion In this exploratory study, QIs were able to capture changes in PEM severity and symptom quality over time, even when VAS scales failed to do so. Measurement of PEM can be improved by using a quantitative–qualitative mixed model approach.

Source: Stussman B, Calco B, Norato G, et al. Mixed methods system for the assessment of post-exertional malaise in myalgic encephalomyelitis/chronic fatigue syndrome: an exploratory study. BMJ Neurology Open 2024;6:e000529. doi: 10.1136/bmjno-2023-000529  https://neurologyopen.bmj.com/content/6/1/e000529 (Full text)

Deep Phenotyping of Neurologic Postacute Sequelae of SARS-CoV-2 Infection

Abstract:

Background and Objectives SARS-CoV-2 infection has been associated with a syndrome of long-term neurologic sequelae that is poorly characterized. We aimed to describe and characterize in-depth features of neurologic postacute sequelae of SARS-CoV-2 infection (neuro-PASC).

Methods Between October 2020 and April 2021, 12 participants were seen at the NIH Clinical Center under an observational study to characterize ongoing neurologic abnormalities after SARS-CoV-2 infection. Autonomic function and CSF immunophenotypic analysis were compared with healthy volunteers (HVs) without prior SARS-CoV-2 infection tested using the same methodology.

Results Participants were mostly female (83%), with a mean age of 45 ± 11 years. The median time of evaluation was 9 months after COVID-19 (range 3–12 months), and most (11/12, 92%) had a history of only a mild infection. The most common neuro-PASC symptoms were cognitive difficulties and fatigue, and there was evidence for mild cognitive impairment in half of the patients (MoCA score <26). The majority (83%) had a very disabling disease, with Karnofsky Performance Status ≤80. Smell testing demonstrated different degrees of microsmia in 8 participants (66%). Brain MRI scans were normal, except 1 patient with bilateral olfactory bulb hypoplasia that was likely congenital. CSF analysis showed evidence of unique intrathecal oligoclonal bands in 3 cases (25%). Immunophenotyping of CSF compared with HVs showed that patients with neuro-PASC had lower frequencies of effector memory phenotype both for CD4+ T cells (p < 0.0001) and for CD8+ T cells (p = 0.002), an increased frequency of antibody-secreting B cells (p = 0.009), and increased frequency of cells expressing immune checkpoint molecules. On autonomic testing, there was evidence for decreased baroreflex-cardiovagal gain (p = 0.009) and an increased peripheral resistance during tilt-table testing (p < 0.0001) compared with HVs, without excessive plasma catecholamine responses.

Discussion CSF immune dysregulation and neurocirculatory abnormalities after SARS-CoV-2 infection in the setting of disabling neuro-PASC call for further evaluation to confirm these changes and explore immunomodulatory treatments in the context of clinical trials.

Source: Yair Mina, Yoshimi Enose-Akahata, Dima A. Hammoud, Anthony J. Videckis, Sandeep R. Narpala, Sarah E. O’Connell, Robin Carroll, Bob C. Lin, Cynthia Chen McMahan, Govind Nair, Lauren B. Reoma, Adrian B. McDermott, Brian Walitt, Steven Jacobson, David S. Goldstein, Bryan R. Smith, Avindra Nath. Deep Phenotyping of Neurologic Postacute Sequelae of SARS-CoV-2 Infection. Neurol Neuroimmunol Neuroinflamm Jul 2023, 10 (4) e200097; DOI: 10.1212/NXI.0000000000200097 

A Mixed Methods System for the Assessment of Post Exertional Malaise in Encephalomyelitis/Chronic Fatigue Syndrome

Abstract:

Background A central feature of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is post exertional malaise (PEM), which is an acute worsening of symptoms after a physical, emotional and/or mental exertion. PEM is also a feature of Long COVID. Dynamic measures of PEM have historically included scaled questionnaires which have not been validated in ME/CFS. To enhance our understanding of PEM and how best to measure it, we conducted semi-structured qualitative interviews (QIs) at the same intervals as Visual Analog Scale (VAS) measures after a Cardiopulmonary Exercise Test (CPET).

Methods Ten ME/CFS and nine healthy volunteers participated in a CPET. For each participant, PEM symptom VAS (7 symptoms) and semi-structured QIs were administered at six timepoints over 72 hours before and after a single CPET. QI data were used to plot the severity of PEM at each time point and identify the self-described most bothersome symptom for each patient. QI data were used to determine the symptom trajectory and peak of PEM. Performance of QI and VAS data were compared to each other using Spearman correlations.

Results QIs documented that each ME/CFS volunteer had a unique PEM experience, with differences noted in the onset, severity, trajectory over time, and most bothersome symptom. No healthy volunteers experienced PEM. Scaled QI data were able to identify PEM peaks and trajectories, even when VAS scales were unable to do so due to known ceiling and floor effects. QI and VAS fatigue data corresponded well prior to exercise (baseline, r=0.7) but poorly at peak PEM (r=0.28) and with the change from baseline to peak (r=0.20). When the most bothersome symptom identified from QIs was used, these correlations improved (r=.0.77, 0.42. and 0.54 respectively) and reduced the observed VAS scale ceiling and floor effects.

Conclusion QIs were able to capture changes in PEM severity and symptom quality over time in all the ME/CFS volunteers, even when VAS scales failed to do so. Information collected from QIs also improved the performance of VAS. Measurement of PEM can be improved by using a quantitative-qualitative mixed model approach.

Disclaimer This research/work/investigator was supported (in part) by the Division of Intramural Research of the National Institutes of Health, NINDS. The content is solely the responsibility of the author(s) and does not necessarily represent the official views of the National Institutes of Health.

Source: Barbara Stussman, Brice Calco, Gina Norato, Angelique Gavin, Snigdha Chigurupati, Avindra Nath, Brian Walitt. A Mixed Methods System for the Assessment of Post Exertional Malaise in Encephalomyelitis/Chronic Fatigue Syndrome. medRxiv 2023.04.24.23288821;  doi: https://doi.org/10.1101/2023.04.24.23288821 https://www.medrxiv.org/content/10.1101/2023.04.24.23288821v1.full-text (Full text)

Neurovascular injury with complement activation and inflammation in COVID-19

Abstract:

The underlying mechanisms by which severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) leads to acute and long-term neurological manifestations remains obscure. We aimed to characterize the neuropathological changes in patients with coronavirus disease 2019 and determine the underlying pathophysiological mechanisms. In this autopsy study of the brain, we characterized the vascular pathology, the neuroinflammatory changes and cellular and humoral immune responses by immunohistochemistry.

All patients died during the first wave of the pandemic from March to July 2020. All patients were adults who died after a short duration of the infection, some had died suddenly with minimal respiratory involvement. Infection with SARS-CoV-2 was confirmed on ante-mortem or post-mortem testing. Descriptive analysis of the pathological changes and quantitative analyses of the infiltrates and vascular changes were performed.

All patients had multifocal vascular damage as determined by leakage of serum proteins into the brain parenchyma. This was accompanied by widespread endothelial cell activation. Platelet aggregates and microthrombi were found adherent to the endothelial cells along vascular lumina. Immune complexes with activation of the classical complement pathway were found on the endothelial cells and platelets. Perivascular infiltrates consisted of predominantly macrophages and some CD8+ T cells. Only rare CD4+ T cells and CD20+ B cells were present. Astrogliosis was also prominent in the perivascular regions. Microglial nodules were predominant in the hindbrain, which were associated with focal neuronal loss and neuronophagia.

Antibody-mediated cytotoxicity directed against the endothelial cells is the most likely initiating event that leads to vascular leakage, platelet aggregation, neuroinflammation and neuronal injury. Therapeutic modalities directed against immune complexes should be considered.

Source: Lee MH, Perl DP, Steiner J, Pasternack N, Li W, Maric D, Safavi F, Horkayne-Szakaly I, Jones R, Stram MN, Moncur JT, Hefti M, Folkerth RD, Nath A. Neurovascular injury with complement activation and inflammation in COVID-19. Brain. 2022 Jul 5:awac151. doi: 10.1093/brain/awac151. Epub ahead of print. PMID: 35788639; PMCID: PMC9278212. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9278212/ (Full text)

Microvascular Injury in the Brains of Patients with Covid-19

To the Editor:

We conducted postmortem high-resolution magnetic resonance imaging (magnetic resonance microscopy) of the brains of patients with coronavirus disease 2019 (Covid-19) (median age, 50 years) and histopathological examination that focused on microvascular changes in the olfactory bulb and brain stem. (See the Materials and Methods section in the Supplementary Appendix, available with the full text of this letter at NEJM.org.) Images were obtained from the brains of 13 patients with the use of an 11.7-Tesla scanner at a resolution of 25 μm for the olfactory bulb and at a resolution of 100 μm for the brain. Abnormalities were seen in the brains of 10 patients.

We examined the brains of patients that showed abnormalities by means of multiplex fluorescence imaging (in 5 patients) and by means of chromogenic immunostaining (in 10 patients). We performed conventional histopathological examination of the brains of 18 patients. Fourteen patients had chronic illnesses, including diabetes and hypertension, and 11 had been found dead or had died suddenly and unexpectedly. Of the 16 patients with available medical histories, 1 had delirium, 5 had mild respiratory symptoms, 4 had acute respiratory distress syndrome, 2 had pulmonary embolism, and the symptoms were not known in 3.

Read the rest of this letter HERE.

Source: Lee MH, Perl DP, Nair G, Li W, Maric D, Murray H, Dodd SJ, Koretsky AP, Watts JA, Cheung V, Masliah E, Horkayne-Szakaly I, Jones R, Stram MN, Moncur J, Hefti M, Folkerth RD, Nath A. Microvascular Injury in the Brains of Patients with Covid-19. N Engl J Med. 2021 Feb 4;384(5):481-483. doi: 10.1056/NEJMc2033369. Epub 2020 Dec 30. PMID: 33378608; PMCID: PMC7787217. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7787217/ (Full text)

Mild respiratory COVID can cause multi-lineage neural cell and myelin dysregulation

Summary:

COVID survivors frequently experience lingering neurological symptoms that resemble cancer therapy-related cognitive impairment, a syndrome for which white-matter microglial reactivity and consequent neural dysregulation is central. Here, we explored the neurobiological effects of respiratory SARS-CoV-2 infection and found white-matter-selective microglial reactivity in mice and humans.
Following mild respiratory COVID in mice, persistently impaired hippocampal neurogenesis, decreased oligodendrocytes and myelin loss were evident together with elevated CSF cytokines/chemokines including CCL11. Systemic CCL11 administration specifically caused hippocampal microglial reactivity and impaired neurogenesis. Concordantly, humans with lasting cognitive symptoms post-COVID exhibit elevated CCL11 levels. Compared to SARS-CoV-2, mild respiratory influenza in mice caused similar patterns of white matter-selective microglial reactivity, oligodendrocyte loss, impaired neurogenesis and elevated CCL11 at early timepoints, but after influenza only elevated CCL11 and hippocampal pathology persisted. These findings illustrate similar neuropathophysiology after cancer therapy and respiratory SARS-CoV-2 infection which may contribute to cognitive impairment following even mild COVID.
Source: Anthony Fernández-Castañeda, Peiwen Lu, Anna C. Geraghty, Eric Song, MyoungHwa Lee, Jamie Wood, Michael R. O’Dea, Selena Dutton, Kiarash Shamardani, Kamsi Nwangwu, Rebecca Mancusi, Belgin Yalçın, Kathryn R. Taylor, Lehi AcostaAlvarez, Karen Malacon, Michael B. Keough, Lijun Ni, Pamelyn J. Woo, Daniel Contreras-Esquivel, Angus Martin Shaw Toland, Jeff R. Gehlhausen, Jon Klein, Takehiro Takahashi, Julio Silva, Benjamin Israelow, Carolina Lucas, Tianyang Mao, Mario A. Peña-Hernández, Alexandra Tabachnikova, Robert J. Homer, Laura Tabacof, Jenna Tosto-Mancuso, Erica Breyman, Amy Kontorovich, Dayna McCarthy, Martha Quezado, Hannes Vogel, Marco M. Hefti, Daniel P. Perl, Shane Liddelow, Rebecca Folkerth, David Putrino, Avindra Nath, Akiko Iwasaki, Michelle Monje. Mild respiratory COVID can cause multi-lineage neural cell and myelin dysregulation.  Cell (2022). Published: June 12, 2022 DOI:https://doi.org/10.1016/j.cell.2022.06.008 https://www.sciencedirect.com/science/article/pii/S0092867422007139 (Full text available as PDF file)

Acute and chronic neurological disorders in COVID-19: potential mechanisms of disease

Abstract:

Coronavirus disease 2019 (COVID-19) is a global pandemic caused by SARS-CoV-2 infection and is associated with both acute and chronic disorders affecting the nervous system. Acute neurological disorders affecting patients with COVID-19 range widely from anosmia, stroke, encephalopathy/encephalitis, and seizures to Guillain-Barré syndrome. Chronic neurological sequelae are less well defined although exercise intolerance, dysautonomia, pain, as well as neurocognitive and psychiatric dysfunctions are commonly reported. Molecular analyses of CSF and neuropathological studies highlight both vascular and immunologic perturbations.

Low levels of viral RNA have been detected in the brains of few acutely ill individuals. Potential pathogenic mechanisms in the acute phase include coagulopathies with associated cerebral hypoxic-ischaemic injury, blood-brain barrier abnormalities with endotheliopathy and possibly viral neuroinvasion accompanied by neuro-immune responses. Established diagnostic tools are limited by a lack of clearly defined COVID-19 specific neurological syndromes. Future interventions will require delineation of specific neurological syndromes, diagnostic algorithm development and uncovering the underlying disease mechanisms that will guide effective therapies.

Source: Balcom EF, Nath A, Power C. Acute and chronic neurological disorders in COVID-19: potential mechanisms of disease. Brain. 2021 Dec 31;144(12):3576-3588. doi: 10.1093/brain/awab302. PMID: 34398188; PMCID: PMC8719840. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8719840/ (Full text)

Nervous system consequences of COVID-19

Although severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is considered a respiratory pathogen, myriad neurologic complications—including confusion, stroke, and neuromuscular disorders—manifest during acute COVID-19. Furthermore, maladies such as impaired concentration, headache, sensory disturbances, depression, and even psychosis may persist for months after infection, as part of a constellation of symptoms now called Long Covid. Even young people with mild initial disease can develop acute COVID-19 and Long Covid neuropsychiatric syndromes. The pathophysiological mechanisms are not well understood, although evidence primarily implicates immune dysfunction, including nonspecific neuroinflammation and antineural autoimmune dysregulation. It is uncertain whether unforeseen neurological consequences may develop years after initial infection. With millions of individuals affected, nervous system complications pose public health challenges for rehabilitation and recovery and for disruptions in the workforce due to loss of functional capacity. There is an urgent need to understand the pathophysiology of these disorders and develop disease-modifying therapies.

Read the rest of this article HERE.

Source: Serena Spudich and Avindra Nath. Nervous system consequences of COVID-19. Science, Volume 375 | Issue 6578, 21 January 2022.