Tag: review

Post-COVID-19 Vaccination (or Long Vax) Syndrome: Putative Manifestation, Pathophysiology, and Therapeutic Options

Abstract:

With the global rollout of COVID-19 vaccines, vaccine safety remains a priority. Emerging concerns have raised the potential risk of a long COVID-like syndrome following vaccination, informally called long Vax and provisionally termed post-COVID-19 vaccination syndrome (PCVS). Our narrative review describes the putative manifestation, pathophysiology, and therapeutic approaches of PCVS based on the available evidence, mostly from case reports/series and observational studies.

Our review noted that PCVS typically manifests within days to weeks post-vaccination, with symptoms lasting months to years. PCVS may present as recognized diagnoses such as postural orthostatic tachycardia syndrome (POTS), small-fibre neuropathy (SFN), myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), or as long-term sequelae of myocarditis, vaccine-induced thrombotic thrombocytopaenia (VITT), or immune thrombocytopaenia purpura (ITP). Symptomatically, PCVS overlaps with long COVID, such as fatigue and brain fog, but PCVS may involve more frequent paraesthesia and less dyspnoea.

We also review pathophysiological hypotheses of PCVS, focussing on the vaccine-derived spike protein and related immune responses. Finally, we discuss potential therapies used to treat patients with PCVS or related conditions, primarily documented in case reports/series, which could guide future clinical research. Overall, PCVS remains a poorly understood condition that requires more research to elucidate its prevalence, prognosis, risk factors, and treatments.

Source: Yong SJ, Kenny TA, Halim A, Munipalli B, Alhashem YN, AlSaihati H, Al-Subaie MF, Al Kaabi NA, Al Fares MA, Garout M, Sabour AA, Alshiekheid MA, Almansour ZH, Alotaibi J, Alrasheed HA, Alamri AA, Albayat H, Alamodi AS, Tombuloglu H, Mohapatra RK, Hazazi A, Rabaan AA. Post-COVID-19 Vaccination (or Long Vax) Syndrome: Putative Manifestation, Pathophysiology, and Therapeutic Options. Rev Med Virol. 2025 Sep;35(5):e70070. doi: 10.1002/rmv.70070. PMID: 40944962. https://pubmed.ncbi.nlm.nih.gov/40944962/

A Perspective on the Role of Metformin in Treating Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and Long COVID

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and Long COVID (LC) are increasingly recognized as debilitating postinfectious conditions that impact both individuals and society. Recent research highlights the potential of metformin, an antidiabetic agent, as a treatment for these syndromes by targeting their underlying mechanisms. This review assesses the effectiveness of metformin in ME/CFS and LC, which involve complex dysfunctions related to cytokines, glycolysis, ATP generation, oxidative stress, gastrointestinal microbiomes, and vascular endothelial function.

Metformin, traditionally known for its antihyperglycemic properties may offer broader therapeutic benefits by influencing these pathological pathways. It works by inhibiting complexes I and IV of the electron transport chain, which reduces the strain on malfunctioning complex V and decreases the production of harmful free radicals. Additionally, metformin’s impact on mTOR signaling could improve energy metabolism in ME/CFS and LC by downregulating an overactive but underperforming protein, thereby alleviating symptoms. Beyond the impact on cellular metabolism, metformin has shown to have anti-inflammatory, vascular, gastrointestinal, neuroprotective and epigenetic effects.

We explore this impact of metformin and the potential role it could play to help people with ME/CFS. While metformin shows promise, it is unlikely to be a stand-alone solution. Instead, it may be part of a broader treatment strategy that includes other therapies targeting neurocognitive and autonomic impairments.

Source: David Fineberg, Alain Moreau, Elena K. Schneider-Futschik, and Christopher W. Armstrong. A Perspective on the Role of Metformin in Treating Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and Long COVID. ACS Pharmacology & Translational Science Article ASAP. DOI: 10.1021/acsptsci.5c00229 https://pubs.acs.org/doi/full/10.1021/acsptsci.5c00229 (Full text)

Mapping cerebral blood flow in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and orthostatic intolerance: insights from a systematic review

Abstract:

Background: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a complex and debilitating condition with a large proportion of patients that experience orthostatic intolerance (OI). This systematic review aimed to assess whether cerebral blood flow (CBF) is reduced in ME/CFS and OI, and whether the presence of both conditions leads to an additional decline in CBF.

Methods: PubMed (from 1943), MEDLINE (from 1946), EMBASE (from 1947) and Cochrane were searched from inception to February 14th, 2025, using terms including “chronic fatigue syndrome”, “myalgic encephalomyelitis”, “orthostatic intolerance” and “cerebral blood flow”. Article selection required the following criteria: published in English; CBF measured in participants with either ME/CFS or OI, or both ME/CFS and OI combined. Quality assessment and risk of bias was assessed using the Newcastle-Ottawa Scale and the systematic review was conducted in accordance with the PRISMA 2020 guidelines.

Results: Of 14,928 articles, 118 were included, 26 (22.1%) of which studied CBF in ME/CFS alone, 81 (68.6%) in OI alone and 11 (9.3%) in both ME/CFS and OI. Overall, the articles included 9185 participants, with a mean age of 39.1 years (SD = 8.8), and 73.8% of participants were female. Studies found CBF was significantly reduced in 12 of the articles focused on ME/CFS and in 56 of those focused on OI; compared to controls. Additionally, in 4 out of 11 studies that examined both conditions, CBF was further reduced in participants suffering from both conditions compared to those with ME/CFS alone.

Conclusions: CBF is reduced in ME/CFS and OI alone and having both conditions comorbidly amplifies CBF reductions. Therefore, observing CBF changes in ME/CFS with and without OI may be important in monitoring disease severity. Despite this, few studies focus on the combination of ME/CFS and OI, and OI may be a confounding factor in CBF in a large portion of ME/CFS studies.

Source: Christopoulos EM, Tantanis D, Huang K, Schneider-Futschik EK, Gooley PR, Moneghetti KJ, Armstrong CW. Mapping cerebral blood flow in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and orthostatic intolerance: insights from a systematic review. J Transl Med. 2025 Aug 26;23(1):963. doi: 10.1186/s12967-025-06954-w. PMID: 40859389. https://translational-medicine.biomedcentral.com/articles/10.1186/s12967-025-06954-w (Full text)

Approach to nursing diagnoses of people with myalgic encephalomyelitis / chronic fatigue syndrome: a qualitative meta-synthesis

Abstract:

Objective: To identify human responses (diagnostic foci) that shape the experience of living with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and how they manifest throughout the course of the illness.

Methods: A qualitative meta-synthesis was conducted. Original studies exploring the experience of living with ME/CFS in adults with a confirmed diagnosis, published in English or Spanish between 1994 and June 2024, were included. The literature search was carried out in Medline/Medline In-Process, Embase, CINAHL, PsycINFO, SCI-EXPANDED, SSCI, SciELO, Lilacs, and Cuiden. Data analysis was based on the human responses (diagnostic foci) from the NANDA-I Nursing Diagnoses Classification, 2021–2023, with findings structured according to Fennell’s Four-Phase Model.

Results: A total of 42 articles were selected. Twenty human responses (diagnostic foci) and three classes of the NANDA-I Nursing Diagnoses Classification were identified, interwoven across the different phases of the model. Some responses were present throughout all phases, while others, such as Energy Balance and Health Self-Management, became particularly relevant from Phase 2 onwards. Phases 3 and 4 were characterised by losses and processes of subjective reconstruction, with diagnostic foci such as Sorrow, Spiritual Distress, and Personal Identity being predominant.

Conclusions: The identified human responses (diagnostic foci) highlight how the contested and chronic nature of ME/CFS profoundly shapes the lived experience of those affected. The model derived from this review provides a structured framework for targeted nursing interventions, aligned with the phase each individual is experiencing.

Source: Oter-Quintana, C., Esteban-Hernandez, J., Cuellar-Pompa, L., Gil-Carballo, C., Brito-Brito, P. R., Martín-García, A., … Alameda-Cuesta, A. (2025). Approach to nursing diagnoses of people with myalgic encephalomyelitis / chronic fatigue syndrome: a qualitative meta-synthesis. Fatigue: Biomedicine, Health & Behavior, 1–32. https://doi.org/10.1080/21641846.2025.2522028 https://www.tandfonline.com/doi/full/10.1080/21641846.2025.2522028

Nutraceutical Supplementation Effects on Subjective Fatigue Symptoms in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Systematic Review

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating condition marked by severe, long-lasting fatigue and exhaustion that does not improve with rest. ME/CFS is reported in individuals of all ages and various racial, socioeconomic, and ethnic groups. This condition lacks standard treatment. Nutritional supplements and dietary interventions are often used to manage symptoms, but the efficacy of these interventions remains scarce in the current literature. This systematic review aims to evaluate and summarize recent evidence on nutrient supplementation and diet-based interventions in patients with ME/CFS sourced from clinical trial registries and article databases.

Registries improve the quality, integrity, and transparency of clinical trials by providing a standardized platform for reporting study design and results and, thus, reducing the biases related to selective reporting practices. Systematic reviews using these registries, therefore, are an efficient pathway to acquire current medical evidence for use in clinical decision-making and the development of practice guidance in various fields. ClinicalTrials.gov, Medline, PubMed, Cochrane, and Web of Science were systematically searched for interventional studies in which patients suffering from ME/CFS supplemented or altered their diet.

The results of this review showed several supplements that suggest improvement in patients’ symptomatology, including nicotinamide adenine dinucleotide (NADH), coenzyme Q10 (CoQ10), wasabi, and probiotics. However, many of these registered clinical trials did not employ the U.S. National Institutes of Health (NIH)’s National Institute of Neurological Disorders and Stroke (NINDS) suggested common data elements (CDEs). These standardized outcome-measuring tools allow the generalization and true comparison of the patient-reported outcomes.

Source: Brito EM, Bonifanti L, Patel R, Jimenez J, Junco J, Rozenfeld IR, Renesca V, Cheema AK. Nutraceutical Supplementation Effects on Subjective Fatigue Symptoms in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Systematic Review. Cureus. 2025 Jul 2;17(7):e87178. doi: 10.7759/cureus.87178. PMID: 40755709; PMCID: PMC12315604. https://pmc.ncbi.nlm.nih.gov/articles/PMC12315604/ (Full text)

Causes of symptoms and symptom persistence in long COVID and myalgic encephalomyelitis/chronic fatigue syndrome

Abstract:

Debilitating symptoms for many years can follow acute COVID-19 (“long COVID”), myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), and various post-acute infection syndromes (PAISs). Together, long COVID and ME/CFS affect 60-400 million individuals, globally. Many similar underlying biological abnormalities have been identified in both conditions including autoantibodies against neural targets, endothelial dysfunction, acquired mitochondrial dysfunction, and a pro-inflammatory gut microbiome. Each of these abnormalities may directly cause some of the symptoms.

In addition, the symptoms also may be caused by ancient, evolutionarily conserved symptomatic and metabolic responses to vital threats-sickness behavior and torpor-responses mediated by specific, recently discovered neural circuits. These neural circuits constitute a symptom-generating pathway, activated by neuroinflammation, which may be targeted by therapeutics to quell neuroinflammation.

Many factors cause the symptoms to become chronic, including persistent infectious agents (and/or their nucleic acids and antigens) and the fact that many of the underlying biological abnormalities reinforce each other, creating ongoing physiological vicious cycles.

Source:Komaroff AL, Dantzer R. Causes of symptoms and symptom persistence in long COVID and myalgic encephalomyelitis/chronic fatigue syndrome. Cell Rep Med. 2025 Jul 25:102259. doi: 10.1016/j.xcrm.2025.102259. Epub ahead of print. PMID: 40744021. https://www.cell.com/cell-reports-medicine/fulltext/S2666-3791(25)00332-5 (Full text)

Inflammation, Autoimmunity, and Infection in Fibromyalgia: A Narrative Review

Abstract:

Fibromyalgia (FM) is a chronic disease characterized by widespread musculoskeletal pain of unknown etiology. The condition is commonly associated with other symptoms, including fatigue, sleep disturbances, cognitive impairment, and depression. For this reason, FM is also referred to as FM syndrome. The nature of the pain is defined as nociplastic according to the latest international classification and is characterized by altered nervous sensitization both centrally and peripherally. Psychosocial conditions have traditionally been considered critical in the genesis of FM. However, recent studies in animal models and humans have provided new evidence in favor of an inflammatory and/or autoimmune pathogenesis.

In support of this hypothesis are epidemiological data of an increased female prevalence, similar to that of autoimmune diseases, and the frequent association with immune-mediated inflammatory disorders. In addition, the observation of an increased incidence of this condition during long COVID revived the hypothesis of an infectious pathogenesis. This narrative review will, therefore, discuss the evidence supporting the immune-mediated pathogenesis of FM in light of the most current data available in the literature.

Source: Paroli M, Gioia C, Accapezzato D, Caccavale R. Inflammation, Autoimmunity, and Infection in Fibromyalgia: A Narrative Review. Int J Mol Sci. 2024 May 29;25(11):5922. doi: 10.3390/ijms25115922. PMID: 38892110; PMCID: PMC11172859. https://pmc.ncbi.nlm.nih.gov/articles/PMC11172859/ (Full text)

Advancing research on regulatory autoantibodies targeting GPCRs: Insights from the 5th international symposium

Abstract:

The 5th International Symposium on Regulatory Autoantibodies Targeting GPCR (RAB-GPCRs) advanced the understanding of the significant role played by autoantibodies targeting G-protein-coupled receptors (GPCRs) in various human diseases. Once considered passive markers, RAB-GPCRs are now recognized as active modulators of cellular signaling, immune regulation, and inflammation.

The symposium highlighted their involvement in multiple prominent pathologies, including autoimmune diseases, cardio- and cerebrovascular diseases, and neuroimmunologic disorders such as myalgic encephalomyelitis/chronic fatigue syndrome and post-COVID-19 syndrome (ME/CFS/PCS), as well as solid organ and hematopoietic stem cell transplantation (SOT/HSCT). Experts from rheumatology, immunology, and neurology presented interdisciplinary discussions on the potential of RAB-GPCRs as biomarkers and therapeutic targets. Advances in screening methods, biomarker identification, and therapeutic strategies were shared, emphasizing their diagnostic potential and application in novel therapeutic interventions.

This report summarizes key insights from the symposium, particularly focusing on the modulatory properties of RAB-GPCRs and their relevance in both immune-mediated diseases and other pathologies (e.g., vascular, degenerative) that are traditionally not considered primarily immune-mediated. Ongoing research is expected to further establish these autoantibodies as crucial components in disease modulation and systems biology contexts, offering new opportunities for precision medicine and improved clinical outcomes in immune-related disorders.

Source: Cabral-Marques O, Schimke LF, Moll G, Filgueiras IS, Nóbile AL, Adri AS, do Vale FYN, Usuda JN, Corrêa YLG, Albuquerque D, Nava RG, Santos RS, Dias HD, Silva HF, Marconi PB, Catar R, Adu-Gyamfi M, Wang P, Khan TA, Hackel AM, Leheis A, Stähle A, Müller A, Schmidt C, Radunovic C, Adjailia EB, Grasshoff H, Humrich JY, Menz J, Fourlakis K, Winziers M, Jäpel M, Wegner MV, Lamprecht P, Nieberding R, Akbarzadeh R, Arnold S, Jendrek S, Klapa S, Augustin S, Biedermann S, Schinke S, Scheerer P, Endres M, Schulze-Forster K, Paul F, Yu X, Sotzny F, Sakmar TP, Banasik M, Haghikia A, Hoffmann MH, Veprintsev D, Witte T, Dalmolin RJS, Ochs HD, Heidecke H, Scheibenbogen C, Shoenfeld Y, Riemekasten G. Advancing research on regulatory autoantibodies targeting GPCRs: Insights from the 5th international symposium. Autoimmun Rev. 2025 Jun 19:103855. doi: 10.1016/j.autrev.2025.103855. Epub ahead of print. PMID: 40543860. https://www.sciencedirect.com/science/article/pii/S1568997225001156 (Full text)

The pivotal role of central sensitization in long COVID, fibromyalgia and myalgic encephalomyelitis/chronic fatigue syndrome

Abstract:

Introduction: Long COVID is a condition characterized by persistent unexplained symptoms following COVID-19 infection. These symptoms are not related to another disease or organ damage and are similar to those in fibromyalgia and myslgic encephalomyelitis/chronic fatigue syndrome (ME/CFS).

Areas covered: The similar clinical and pathophysiological features and management of long COVID, fibromyalgia and ME/CFS are explored from the unifying framework of central sensitivity syndromes. The article is based on a literature search utilizing PubMed for content published between 2021 and 1 May 2025, using search terms: long COVID, long COVID syndrome, post-COVID-19, post-acute SARS-CoV-2, fibromyalgia, ME/CFS, post-exertional malaise and central sensitization.

Expert opinion: Once long COVID is redefined to exclude patients with well-defined organ disease, it fits best as a model of central sensitization. Long COVID is a single syndrome, rather than many distinct diseases. Optimal management of long COVID and similar central sensitivity

Source: Goldenberg DL. The pivotal role of central sensitization in long COVID, fibromyalgia and myalgic encephalomyelitis/chronic fatigue syndrome. Expert Rev Neurother. 2025 Jun 13:1-17. doi: 10.1080/14737175.2025.2516097. Epub ahead of print. PMID: 40512228. https://www.tandfonline.com/doi/full/10.1080/14737175.2025.2516097

Ignored, dismissed, and minimized: Understanding the harmful consequences of invalidation in health care-A systematic meta-synthesis of qualitative research

Abstract:

The upsurge in the prevalence of contested, ambiguous, and difficult-to-diagnose illnesses presents challenges for clinicians who too often respond by invalidating patients’ symptoms. Although numerous qualitative studies have reported the effects of invalidation on patients’ psychological and behavioral outcomes, this body of research has not been systematically reviewed. Informed by Linehan’s (1993) conceptualization of invalidation, this systematic review elucidated the negative consequences, of symptom invalidation, or the dismissal or minimization of a person’s experiences with illness.

We reviewed 151 qualitative reports representing 11,307 individuals with Ehlers-Danlos syndrome, endometriosis, fibromyalgia syndrome, Gulf War syndrome, irritable bowel syndrome, long COVID, multiple chemical sensitivity, myalgic encephalomyelitis/chronic fatigue syndrome, postural orthostatic tachycardia syndrome, systemic lupus erythematosus, and vulvodynia.

Consistent with Linehan’s theorizing, thematic analysis identified four broad classes of consequences: induced emotional states and beliefs (e.g., shame, suicidality), induced health care emotional states and beliefs (e.g., health care-related anxiety and trauma), induced health care behavior (e.g., health care system avoidance), and diagnostic delay.

Informed by these findings, we developed a novel conceptual model explaining how symptom invalidation leads to these consequences and thereby undermines health outcomes. Future work should explore the proposed conceptual model and identify theoretically informed interventions and policies aimed at preventing symptom invalidation to improve psychological, behavioral, and health outcomes. (PsycInfo Database Record (c) 2025 APA, all rights reserved).

Source: Bontempo AC, Bontempo JM, Duberstein PR. Ignored, dismissed, and minimized: Understanding the harmful consequences of invalidation in health care-A systematic meta-synthesis of qualitative research. Psychol Bull. 2025 Apr;151(4):399-427. doi: 10.1037/bul0000473. PMID: 40310228. https://psycnet.apa.org/fulltext/2026-10154-001.html (Full text)