Brain FADE syndrome: the final common pathway of chronic inflammation in neurological disease

Abstract:

Importance: While the understanding of inflammation in the pathogenesis of many neurological diseases is now accepted, this special commentary addresses the need to study chronic inflammation in the propagation of cognitive Fog, Asthenia, and Depression Related to Inflammation which we name Brain FADE syndrome. Patients with Brain FADE syndrome fall in the void between neurology and psychiatry because the depression, fatigue, and fog seen in these patients are not idiopathic, but instead due to organic, inflammation involved in neurological disease initiation.

Observations: A review of randomized clinical trials in stroke, multiple sclerosis, Parkinson’s disease, COVID, traumatic brain injury, and Alzheimer’s disease reveal a paucity of studies with any component of Brain FADE syndrome as a primary endpoint. Furthermore, despite the relatively well-accepted notion that inflammation is a critical driving factor in these disease pathologies, none have connected chronic inflammation to depression, fatigue, or fog despite over half of the patients suffering from them.

Conclusions and relevance: Brain FADE Syndrome is important and prevalent in the neurological diseases we examined. Classical “psychiatric medications” are insufficient to address Brain FADE Syndrome and a novel approach that utilizes sequential targeting of innate and adaptive immune responses should be studied.

Source: Khalid A. Hanafy, Tudor G. Jovin. Brain FADE syndrome: the final common pathway of chronic inflammation in neurological disease. Front. Immunol., 17 January 2024, Sec. Inflammation, Volume 15 – 2024 | https://doi.org/10.3389/fimmu.2024.1332776 https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2024.1332776/full (Full text)

Immune cell exhaustion, dysfunction, and metabolism in myalgic encephalomyelitis/chronic fatigue syndrome

Abstract;
Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a chronic and incapacitating multisystem condition with unknown etiology, no cure, and no FDA- approved treatments, all of which can be attributed to historical underfunding, widespread misinformation, and the complexity of the disease. Many patients encounter several immune-related symptoms, extreme fatigue, post-exertional malaise, and a flu-like onset. Studies have documented changes in ME/CFS immune cell populations and decreased natural killer (NK) cell performance, along with aberrant cytokine production, reduced glycolysis in T cells, and altered metabolites relevant to fatty acid oxidation, implicating potential intracellular metabolic dysregulation.
This knowledge prompted me to investigate fatty acid oxidation and immune cell functional states in isolated ME/CFS lymphocytes. Using extracellular flux analysis and flow cytometry, I observed elevated fatty acid oxidation levels in ME/CFS immune cells, including NK cells, CD4+ memory cells, CD4+ effector cells, CD8+ naïve cells, and CD8+ memory cells compared to healthy controls, particularly during high energy demands and activation. My findings suggest a metabolic dysfunction in ME/CFS immune cells, consistent with T cell exhaustion – a state that hinders immune cell proliferation, survival, and cytokine production following persistent antigen stimulation.
Building upon these results, I further investigated immune cell exhaustion and dysfunction in isolated CD8+ and CD4+ T cells from ME/CFS and healthy samples. I analyzed T cell sub-populations, including naïve, effector, memory, regulatory, and helper T cells, for frequencies of inhibitory receptors and transcription factors associated with dysfunctional immune cell states.
I detected distinct transcription factor dynamics and elevated exhausted T cell phenotype proportions in ME/CFS CD8+ T cell populations compared to healthy controls. In ME/CFS CD4+ T cells, I also observed altered inhibitory receptor population frequencies compared to healthy control samples. Moreover, dysfunctional T cell features correlated with ME/CFS health status and symptom presentation.
Overall, my findings detect dysfunctional T cell states in specific ME/CFS cell populations, which can lead to reduced effector function that may contribute to ME/CFS symptom presentation. This work highlights the significance of assessing both metabolic components and immune cell dysfunction-associated targets in the development of potential therapeutic interventions for individuals with ME/CFS.
Source: Maya, Jessica. Immune cell exhaustion, dysfunction, and metabolism in myalgic encephalomyelitis/chronic fatigue syndrome. Cornell Theses and Dissertations. 2024. https://ecommons.cornell.edu/items/242f8723-6f87-47cc-b36d-bf51a21f4255

Unequal access to diagnosis of myalgic encephalomyelitis in England

Abstract:

Background People with Myalgic Encephalomyelitis (ME/CFS; sometimes referred to as chronic fatigue syndrome) experience very poor health-related quality of life and only rarely recover. ME/CFS has no curative treatment and no single diagnostic test. Public health and policy decisions relevant to ME/CFS require knowledge of its prevalence and barriers to diagnosis. However, people with ME/CFS report lengthy diagnostic delays and widespread misunderstanding of their symptoms. Published prevalence estimates vary greatly by country, gender, age and ethnicity.

Methods Hospital Episode Statistics data is routinely collected by the NHS in England together with patient age, gender and ethnicity. This data, downloaded from the Feasibility Self-Service of NHS DigiTrials, was used to stratify individuals with the ICD-10 code that best reflects ME/CFS symptoms (G93.3; “Postviral fatigue syndrome”) according to their age, self-reported gender and ethnicity, General Practice and NHS England Integrated Care Board (ICB).

Results In all, 100,055 people in England had been diagnosed with ME/CFS (ICD-10:G93.3) between April 1 1989 and October 7 2023, 0.16% of all registered patients. Of these, 79,445 were females and 20,590 males, a female-to-male ratio of 3.88:1. Female relative to male prevalence peaked at about 6-to-1 in individuals’ fourth and fifth decades of life. Prevalence varied widely across the 42 ICBs: 0.086%-0.82% for females and 0.024%-0.21% for males. White individuals were approximately 5-fold more likely to be diagnosed with ME/CFS than others; black, Asian or Chinese ethnicities are associated with particularly low rates of ME/CFS diagnoses. This ethnicity bias is stronger than for other common diseases. Among active English GP practices, 176 (3%) had no registered ME/CFS patients. Eight ICBs (19%) each contained fewer than 8 other-than-white individuals with a G93.3 code despite their registers containing a total of 293,770 other-than-white patients.

Conclusion Those who are disproportionately undiagnosed with ME/CFS are other-than-white ethnic groups, older females (>60y), older males (>80y), and people living in areas of multiple deprivation. The lifetime prevalence of ME/CFS for English females and males may be as high as 0.92% and 0.25%, respectively, or approximately 390,000 UK individuals overall. This improved estimate of ME/CFS prevalence allows more accurate assessment of the socioeconomic and disease burden imposed by ME/CFS.

Source: Gemma L. Samms, Chris P. Ponting. Unequal access to diagnosis of myalgic encephalomyelitis in England. medRxiv 2024.01.31.24302070; doi: https://doi.org/10.1101/2024.01.31.24302070 https://www.medrxiv.org/content/10.1101/2024.01.31.24302070v1.full-text (Full text)

Clinical and Laboratory Characteristics of Fatigue-dominant Long-COVID subjects: A Cross-Sectional Study

Abstract:

Background: Long-COVID is defined by persistent symptoms following COVID-19 infection. Approximately 71% of individuals with long-COVID experience ongoing fatigue, post-exertional malaise, and cognitive impairments, which share pathological similarities with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). This similarity has prompted studies to explore the characteristics of long-COVID to gain a better understanding of ME/CFS. To gain insights, we investigated the clinical and laboratory characteristics of individuals with fatigue-dominant long-COVID.

Methods: We enrolled 100 subjects (36 males, 64 females) with long-COVID who had a higher score than 60 in modified Korean version of the Chalder Fatigue Scale (mKCFQ11) and higher than 5 in fatigue-focused Visual Analogue Scale (VAS). To investigate fatigue symptoms, the mKCFQ11, the Multidimensional Fatigue Inventory (MFI-20), and VAS for fatigue and brain-fog, along with the Short Form Survey (SF-12) were employed. We also measured three cytokines and cortisol levels for immunological and endocrinological indicators. As a cross-sectional observational study, the data were collected at a single point in time.

Results: The mean scores on the measurements showed severe fatigue, and these scores were significantly correlated, with no differences based on sex, the post-COVID period, or age. Among the laboratory tests, plasma cortisol levels had a significant negative correlation with fatigue scores and a positive correlation with living quality. The negative correlation between cortisol levels and mKCFQ11 scores appeared to be more specific to mental fatigue than physical, which conflicted with other measurements.

Conclusion: Our findings provide the first insights into the characteristics of fatigue in individuals with long-COVID, particularly in terms of fatigue severity and cortisol levels. These results serve as valuable reference data for clinicians dealing with fatigue symptoms in long-COVID patients and for researchers exploring post-viral fatigue symptoms, including ME/CFS, in the future.

Source: Lee JS, Choi Y, Joung JY, Son CG. Clinical and Laboratory Characteristics of Fatigue-dominant Long-COVID subjects: A Cross-Sectional Study. Am J Med. 2024 Feb 6:S0002-9343(24)00057-3. doi: 10.1016/j.amjmed.2024.01.025. Epub ahead of print. PMID: 38331137. https://pubmed.ncbi.nlm.nih.gov/38331137/

Correspondence: Inaccurate reference leads to tripling of reported FND prevalence

Highlights:

  • Perez et al asserted that FND is the “2nd most common” diagnosis in outpatient neurology.
  • Stone et al (2010), cited by Perez et al, does not support the “2nd most common” claim.
  • In Stone et al, a broad “functional/psychological” category was the second most common
  • •

    FND is not synonymous with the “functional/psychological” category in Stone et al.

To the editor:

An article in NeuroImage: Clinical, “Neuroimaging in functional neurological disorder: state of the field and research agenda” (Perez et al., 2021), cited a prominent paper (Stone et al., 2010) as evidence for the assertion that functional neurological disorder (FND) is the “2nd most common outpatient neurologic diagnosis.” Although studies have yielded varying FND prevalence rates, the claim that it is the second-most common diagnosis at outpatient neurology clinics represents an erroneous interpretation of the findings of the referenced 2010 paper.

FND is the current name for what was formerly called conversion disorder, the diagnosis previously given to patients believed to have psychogenic motor and gait dysfunctions, sensory deficits, and non-epileptic seizures. According to the 2013 edition of the Diagnostic and Statistical Manual of Mental Disorders and as noted in Perez et al, FND is not a diagnosis of exclusion but requires the presence of specific “rule-in” clinical signs believed to be incompatible with known neurological disease. Some of these clinical signs have long been used by neurologists and other clinicians to help them identify cases of conversion disorder.

Stone et al.,’s (2010) paper was one of several arising from the Scottish Neurological Symptoms Study (SNSS). The study reviewed records from multiple outpatient neurology clinics and reported that 209 of 3781 attendees, or less than 6 %, received diagnoses compatible with conversion disorder–in other words, what would now be called FND. In terms of ranking, this group of patients—labeled in the SNSS as having “functional” symptoms or diagnoses–was far down the list. The study found higher rates of many other conditions, including headache (19 %), epilepsy (14 %), peripheral nerve disorders (11 %), miscellaneous neurological disorders (10 %), multiple sclerosis/demyelination (7 %), spinal disorders (6 %) and Parkinson’s disease/movement disorders (6 %).

Earlier this year, a paper in the European Journal of Neurology (Mason et al., 2023) cited a different SNSS paper (Stone et al., 2009) to support the assertion that FND prevalence at outpatient neurology clinics was 5.4 %—far lower than the percentage needed to be the “2nd most common” diagnosis. Moreover, the authors of another paper (Foley et al., 2022) have recently issued a correction for the same misstatement of FND prevalence from the SNSS findings as the one identified in Perez et al.

The assertion that the SNSS found FND to be the “2nd most common” diagnosis at outpatient neurology clinics is based on a parallel and commonly repeated claim that the study found the prevalence in these settings to be 16 % (e.g. Ludwig et al., 2018). That rate is almost three times the 5.4 % prevalence recently highlighted in Mason et al. The extra patients included in this greatly expanded FND category were another 10 % collectively identified in the SNSS as having “psychological” symptoms or diagnoses. These “psychological” patients fell into a range of clinical sub-categories, among them hyperventilation, anxiety and depression, atypical facial/temporomandibular joint pain, post-head injury symptoms, fibromyalgia, repetitive strain injury, and alcohol excess. The SNSS paper cited in Perez et al reported that a combined grouping of the patients with “functional and psychological” symptoms or diagnoses had a prevalence of 16 % but did not provide any evidence that the 10 % included under the “psychological” label met, or could have met, the explicit FND requirement for rule-in clinical signs.

FND is not synonymous with the broader “functional and psychological” category in the SNSS and should not be presented as if it were. The post-hoc reinterpretation of previously reported data in a way that conflates FND with other complex conditions—almost tripling its apparent prevalence in the process–is an example of the phenomenon known as diagnostic creep. In any event, the SNSS results are a matter of record. Whatever future studies might determine about FND rates, the published findings cited by Perez et al and addressed in this letter do not support either the claim that it is the “2nd most common” diagnosis in outpatient neurology clinics or the related claim that its prevalence at these venues is 16 %.

Sincerely–

David Tuller (corresponding author)

Center for Global Public Health

School of Public Health

University of California, Berkeley

Berkeley, CA, USA

David Davies-Payne

Department of Radiology

Starship Children’s Hospital

Auckland, New Zealand

Jonathan Edwards

Department of Medicine

University College London

London, England, UK

Keith Geraghty

Centre for Primary Care and Health Services Research

Faculty of Biology, Medicine and Health

University of Manchester

Manchester, England, UK

Calliope Hollingue

Center for Autism and Related Disorders/Kennedy Krieger Institute

Department of Mental Health/Johns Hopkins Bloomberg School of Public Health

Johns Hopkins University

Baltimore, MD, USA

Mady Hornig

Department of Epidemiology

Columbia University Mailman School of Public Health

New York, NY, USA

Brian Hughes

School of Psychology

University of Galway

Galway, Ireland

Asad Khan

North West Lung Centre

Manchester University Hospitals

Manchester, England, UK

David Putrino

Department of Rehabilitation Medicine

Icahn School of Medicine at Mt Sinai

New York, NY, USA

John Swartzberg

Division of Infectious Diseases and Vaccinology

School of Public Health

University of California, Berkeley

Berkeley, CA, USA

Source: Correspondence: Inaccurate reference leads to tripling of reported FND prevalence. Neuroimage Clin. 2024 Feb 7;41:103537. doi: 10.1016/j.nicl.2023.103537. Epub ahead of print. PMID: 38330816. https://www.sciencedirect.com/science/article/pii/S2213158223002280 (Full text)

Postacute Sequelae of SARS-CoV-2 in Children

Abstract:

The coronavirus disease 2019 (COVID-19) pandemic has caused significant medical, social, and economic impacts globally, both in the short and long term. Although most individuals recover within a few days or weeks from an acute infection, some experience longer lasting effects. Data regarding the postacute sequelae of severe acute respiratory syndrome coronavirus 2 infection (PASC) in children, or long COVID, are only just emerging in the literature. These symptoms and conditions may reflect persistent symptoms from acute infection (eg, cough, headaches, fatigue, and loss of taste and smell), new symptoms like dizziness, or exacerbation of underlying conditions. Children may develop conditions de novo, including postural orthostatic tachycardia syndrome, myalgic encephalomyelitis/chronic fatigue syndrome, autoimmune conditions and multisystem inflammatory syndrome in children.

This state-of-the-art narrative review provides a summary of our current knowledge about PASC in children, including prevalence, epidemiology, risk factors, clinical characteristics, underlying mechanisms, and functional outcomes, as well as a conceptual framework for PASC based on the current National Institutes of Health definition. We highlight the pediatric components of the National Institutes of Health-funded Researching COVID to Enhance Recovery Initiative, which seeks to characterize the natural history, mechanisms, and long-term health effects of PASC in children and young adults to inform future treatment and prevention efforts. These initiatives include electronic health record cohorts, which offer rapid assessments at scale with geographical and demographic diversity, as well as longitudinal prospective observational cohorts, to estimate disease burden, illness trajectory, pathobiology, and clinical manifestations and outcomes.

Source: Suchitra Rao, MBBS, MSCS; Rachel S. Gross, MD, MS; Sindhu Mohandas, MD; Cheryl R. Stein, PhD; Abigail Case, MD; Benard Dreyer, MD; Nathan M. Pajor, MD; H. Timothy Bunnell, PhD; David Warburton, MD; Elizabeth Berg, MD; Jonathan B. Overdevest, MD; Mark Gorelik, MD; Joshua Milner, MD; Sejal Saxena, BA; Ravi Jhaveri, MD; John C. Wood, MD, PhD; Kyung E. Rhee, MD, MSc, MA; Rebecca Letts, BA; Christine Maughan, BS; Nick Guthe, BA; Leah Castro-Baucom, MA; Melissa S. Stockwell, MD, MPH. Postacute Sequelae of SARS-CoV-2 in Children. Pediatrics e2023062570. https://doi.org/10.1542/peds.2023-062570 https://publications.aap.org/pediatrics/article/doi/10.1542/peds.2023-062570/196606/Postacute-Sequelae-of-SARS-CoV-2-in-Children (Full text)

Low-dose naltrexone and NAD+ for the treatment of patients with persistent fatigue symptoms after COVID-19

Highlights:

  • A subset of patients experienced persistent fatigue symptoms after COVID-19.
  • Treatment with low-dose naltrexone (LDN) and NAD+ was well tolerated.
  • Treatment increased SF-36 quality of life scores.
  • Treatment also improved fatigue symptom scores.
  • A subset of patients were clinically responsive.

Abstract:

A subset of patients experiences persistent fatigue symptoms after COVID-19, and patients may develop long COVID, which is characterized by lasting systemic symptoms. No treatments for this condition have been validated and are urgently warranted.

In this pilot study, we assessed whether treatment with low-dose naltrexone (LDN, 4.5 mg/day) and supplementation with NAD + through iontophoresis patches could improve fatigue symptoms and quality of life in 36 patients with persistent moderate/severe fatigue after COVID-19.

We detected a significant increase from baseline in SF-36 survey scores after 12 weeks of treatment (mean total SF-36 score 36.5 [SD: 15.6] vs. 52.1 [24.8]; p < 0.0001), suggestive of improvement of quality of life. Furthermore, participants scored significantly lower on the Chalder fatigue scale after 12 weeks of treatment (baseline: 25.9 [4.6], 12 weeks: 17.4 [9.7]; p < 0.0001).

We found a subset of 52 % of patients to be responders after 12 weeks of treatment. Treatment was generally safe, with mild adverse events previously reported for LDN, which could be managed with dose adjustments. The iontophoresis patches were associated with mild, short-lived skin irritation in 25 % of patients.

Our data suggest treatment with LDN and NAD+ is safe and may be beneficial in a subset of patients with persistent fatigue after COVID-19. Larger randomized controlled trials will have to confirm our data and determine which patient subpopulations might benefit most from this strategy.

Source: Anar Isman, Andy Nyquist, Bailey Strecker, Girish Harinath, Virginia Lee, Xingyu Zhang, Sajad Zalzala. Low-dose naltrexone and NAD+ for the treatment of patients with persistent fatigue symptoms after COVID-19. Brain, Behavior, & Immunity – Health, Volume 36, 2024, 100733, ISSN 2666-3546, https://doi.org/10.1016/j.bbih.2024.100733. https://www.sciencedirect.com/science/article/pii/S2666354624000115 (Full text)

Haematological sequelae in the post-acute phase of symptomatic SARS-CoV-2 infection

Abstract:

Many patients surviving SARS-CoV-2 infection suffer from long-term symptoms (long COVID or post COVID) such as shortness of breath, fatigue, loss of taste or smell and cognitive deterioration. However, few data are available concerning blood cell counts and haematological parameters during the post-COVID period.

We analysed haematological data from 83 patients previously admitted to the internal medicine unit of our institution because of symptomatic SARS-CoV-2 infection; all data were obtained within 1-12 months from disease onset. A control group of 70 apparently healthy, age- and sex-matched COVID-19 negative individuals was assessed for comparison. Blood cell counts improved in the post-COVID period, but 81% of patients had persistent abnormalities, compared with 50% in the control group, p < 0.001.

Most common haematological findings included anaemia (40%), reduced lymphocyte (43%) or eosinophil counts (38%) and low IgM memory B cells and correlated with advanced age, number of chronic comorbidities, female gender, altered renal function, reduced baseline Hb and procalcitonin concentrations and increased RDW. Data on lymphocytes and IgM memory B cells show that impaired immune responses may persist for up to one year in the post-COVID period, possibly contributing to long-term symptoms, especially in female patients.

Source: Bergamaschi G, Barteselli C, Calabretta F, Lenti MV, Merli S, Rossi CM, Di Sabatino A. Haematological sequelae in the post-acute phase of symptomatic SARS-CoV-2 infection. Intern Emerg Med. 2024 Jan;19(1):125-133. doi: 10.1007/s11739-023-03459-6. Epub 2023 Nov 24. PMID: 38001354. https://pubmed.ncbi.nlm.nih.gov/38001354/

Decreased risk of COVID-19 and long COVID in patients with psoriasis receiving IL-23 inhibitor: A cross-sectional cohort study from China

Abstract:

Background: Although clinical trials and real-world data suggest that the risk of COVID-19 and its complications is not exacerbated in patients with psoriasis treated by biological agents, the evidence for this is still limited.

Objectives: We aimed to assess the outcomes of COVID-19 among Chinese patients with psoriasis treated by IL-23 inhibitor, and to compare these variables in patients receiving other therapies.

Methods: A cross-sectional cohort study was conducted to compare psoriasis treatment with IL-23 inhibitor to other treatment methods. All the patients received a questionnaire that contained questions about their psoriasis treatment, COVID-19 symptoms, and related risk factors. The prevalence of COVID-19 was calculated, and logistic regression analyses were performed to determine the association between treatment method and COVID-19 risk. The symptoms of COVID-19 and long COVID were described for each treatment group.

Results: Between December 2022 and February 2023, 732 patients with psoriasis were included in the final analysis. 549 patients had a SARS-CoV-2 infection during the study period. Our results showed that individuals who worked outdoors had a decreased risk of COVID-19, as did those who had other allergic disease. With regard to the effect of the treatment regimens, IL-23 inhibitor treatment was associated with a decreased risk of COVID-19 compared to almost all the other treatments except acitretin. Fever was the most common symptom, but the maximum temperature and duration of fever were comparable among the treatment groups. Patients treated with IL-23 inhibitor were more likely to be asymptomatic after recovery compared to patients treated with methotrexate, narrow-bound ultra violet B, or TNF-α inhibitor.

Conclusions: IL-23 inhibitor treatment may lower the risk of COVID-19 and long COVID. Thus, IL-23 inhibitor treatment might be beneficial and positively considered for patients with psoriasis who require systemic treatment during periods when there is a surge in COVID-19 cases.

Source: Hu Y, Huang D, Jiang Y, Yu Q, Lu J, Ding Y, Shi Y. Decreased risk of COVID-19 and long COVID in patients with psoriasis receiving IL-23 inhibitor: A cross-sectional cohort study from China. Heliyon. 2024 Jan 9;10(2):e24096. doi: 10.1016/j.heliyon.2024.e24096. PMID: 38293509; PMCID: PMC10826651. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10826651/ (Full text)

Herbal Medicines for Long COVID: A Phase 2 Pilot Clinical Study

Abstract:

Background: Infections of Coronavirus Disease-2019 (COVID-19) can cause long-term effects known as long COVID. This pilot study aimed to evaluate the feasibility of a clinical study as well as the efficacy and safety of traditional East Asian herbal medicines in alleviating fatigue and cognitive dysfunction “brain fog” in patients with long COVID.

Methods: This prospective pilot study investigated the use of three types of herbal medicines, Bojungikki-tang (BIT), Kyungok-go (KOG), and Cheonwangbosim-dan (CBD), for a 12-week period as potential treatments for fatigue and cognitive dysfunction in patients with long COVID. Forty-five patients with long COVID were recruited, and one of three drugs was given based on the patient’s symptoms and pattern identification. The effect of herbal medications on fatigue and cognitive function outcomes was assessed over a 36-week period, with patient adherence closely monitored.

Results: After 12 weeks of herbal drug administration, fatigue symptoms improved significantly across all groups, with treatment success rates of 80%, 53.33%, and 46.67% in the BIT, KOG, and CBD groups, respectively. However, “brain fog” symptoms showed less improvement, with treatment success rates of 40%, 46.67%, and 13.33% in the BIT, KOG, and CBD groups, respectively. All adverse events reported were mild and unrelated to the medication. The study design was found to be feasible with high medication adherence.

Conclusions: This study demonstrated the feasibility of conducting a clinical trial with three herbal medicines to treat long COVID symptoms like fatigue and “brain fog.”

Source:Kim, T.; Yoon, J.; Kim, S.; Kang, B.; Kang, J.W.; Kwon, S. Herbal Medicines for Long COVID: A Phase 2 Pilot Clinical Study. Preprints 2024, 2024011605. https://doi.org/10.20944/preprints202401.1605.v1 https://www.preprints.org/manuscript/202401.1605/v1 (Full text available as PDF file)