Health outcomes one year after Omicron infection among 12,789 adults: a community-based cross-sectional study

Summary:

Background: Characterizing the paradigm and impact of long COVID is crucial for addressing this worldwide health challenge. This study aimed to investigate the prevalence of long COVID one year after primary Omicron infection and characterize differences in long-term health consequence between participants with persistent long COVID and those who fully recovered.

Methods: This a community-based cross-sectional study conducted from December 2023 to March 2024 at the China-Japan Friendship Hospital and 16 administrative districts in Beijing. 12,789 participants infected with Omicron between December 2022 and January 2023 were recruited through stratified multistage random sampling and included in the final analysis. Of them, 376 participants with persistent long COVID and 229 without long COVID were matched for further physical examinations. The primary outcome was the prevalence of long COVID one year after infection. Secondary outcomes included muscle strength, exercise capacity, health-related quality of life (HRQoL), mental health, work status, laboratory tests, and examinations.

Findings: Among 12,789 participants (media [IQR] age, 48.4 [37.3 to 61.4] years; 7817 females [61.1%]), 995 of them (7.8%) experienced long COVID within one year, with 651 (5.1%) having persistent symptoms. Fatigue (598/995 [60.1%]) and post-exertional malaise (367/995 [36.9%]) were the most common symptoms. Brain fog had the lowest resolution proportion as 4.2% within one year. The odds of long COVID increased with reinfections (odds ratios for one reinfection 2.592 [95% CI: 2.188 to 3.061]; two or more: 6.171 [3.227 to 11.557]; all p < 0.001). Participants with persistent long COVID had markedly lower muscle strength (upper-limb: 26.9 ± 12.4 vs. 29.1 ± 14.5 Kg; lower-limb: 40.0 [27.0 to 62.0] vs. 43.0 [28.0 to 59.0] s), worse exercise capacity and poorer HRQoL, and meaningful difference in laboratory tests results compared to those without long COVID. They also exhibited significantly higher proportions of abnormal lung function (FEV1 %pred<80%: 13.0% vs. 2.0%; DLco %pred<80%: 32.7% vs. 19.9%) and lung imaging abnormalities (23.5% vs. 13.6%).

Interpretation: The considerable health burden of long COVID and the progression of neurological symptoms following Omicron infection warrant close monitoring. Utilizing professional questionnaires and developing reliable diagnostic tools are necessary for improving diagnosis and treatment of long COVID.

Funding: This work was supported by Beijing Research Center for Respiratory Infectious Diseases (BJRID2024-012), Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences (2022-I2M-CoV19-005/CIFMS 2021-I2M-1-048), the National Natural Science Foundation of China (82241056/82200114/82200009), the New Cornerstone Science Foundation.

Source: Zhang, Hui et al.Health outcomes one year after Omicron infection among 12,789 adults: a community-based cross-sectional study. The Lancet Regional Health – Western Pacific, Volume 0, Issue 0, 101507  https://www.thelancet.com/journals/lanwpc/article/PIIS2666-6065(25)00044-6/fulltext (Full text)

Gulf War Illness: A Historical Review and Considerations of a Post-Viral Syndrome

Abstract:

Gulf War Illness (GWI) is a condition that affects 30-40% of nearly 700,000 Veterans who were deployed to Operations Desert Shield/Storm/Sabre (ODS/S/S) between August 1990 and June 1991 and is characterized by a constellation of symptoms, including fatigue, mood/cognition, chronic pain, gastrointestinal (most frequently referred to as “irritable bowel syndrome”), respiratory, and skin issues.

We review the development of various case definitions for GWI, as well as exposure theories. Despite heavy investment in research, both the pathophysiology and underlying cause of GWI remain areas of active inquiry. Similarities have previously been noted in symptomatology between GWI and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), and more recently, long COVID (LC), a late effect of infection with the Severe Acute Respiratory Syndrome Corona Virus-2 (SARS-CoV-2).

These conditions are discussed with respect to the similarities of their symptomatology and pathophysiology. Long COVID is a post-viral syndrome, and ME/CFS is widely considered to be likely post-infectious as well. This comparison leads to the proposal of the hypothesis that GWI may also be post-viral. Given the similarity of GWI and LC, it is possible that Veterans with GWI had an antecedent infection with a virus related to SARS-CoV-2, potentially the Middle East Respiratory Syndrome Coronavirus (MERS) or an ancestor of this virus. The MERS antibodies have been found in dromedary camels in Saudi Arabia since 1983 to the present, including the time of ODS/S/S. There is abundant evidence to support further investigation into this topic.

Source: Bast E, Jester DJ, Palacio A, Krengel M, Reinhard M, Ashford JW. Gulf War Illness: A Historical Review and Considerations of a Post-Viral Syndrome. Mil Med. 2025 Mar 21:usaf092. doi: 10.1093/milmed/usaf092. Epub ahead of print. PMID: 40117126. https://pubmed.ncbi.nlm.nih.gov/40117126/

Efficacy of vitamin D replacement therapy on 28 cases of myalgic encephalomyelitis/chronic fatigue syndrome after COVID-19 vaccination

Abstract:

Background: Prolonged symptoms have been reported following both COVID-19 infection and vaccination, with some cases leading to myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Of 80 patients presenting to our hospital with postvaccination syndrome, 28 met the diagnostic criteria for ME/CFS. We conducted a retrospective study on these 28 patients.

Methods: We measured serum 25-hydroxyvitamin D levels in 28 patients who developed ME/CFS after COVID-19 vaccination between August 2022 and February 2024. Vitamin D replacement therapy included dietary counseling, sun exposure recommendations, and oral vitamin D supplementation. We evaluated changes in blood vitamin D levels and symptom improvement.

Results: At initial visit, 27 of 28 patients diagnosed with ME/CFS had insufficient or deficient serum 25-hydroxyvitamin D levels (16 ± 4 ng/mL, mean ± SD). Following vitamin D replacement therapy, we observed an increase in blood vitamin D levels (28 ± 5 ng/mL) associated with a decrease in ME/CFS diagnostic symptoms (from 10.3 ± 2.1 to 3.3 ± 2.0). Notably, 23 of 28 patients (82%) no longer met ME/CFS diagnostic criteria after the therapy. Among the symptoms, sleep problems showed the most improvement (71%), followed by autonomic symptoms (68%).

Conclusions: For patients developing ME/CFS after COVID-19 vaccination with insufficient or deficient vitamin D levels, appropriate vitamin D replacement therapy under medical guidance may lead to symptomatic relief. We are preparing a randomized controlled trial to evaluate the efficacy of vitamin D replacement therapy in individuals with ME/CFS who have developed vitamin D deficiency following COVID-19 infection or vaccination.

Source: Kodama S, Konishi N, Hirai Y, Fujisawa A, Nakata M, Teramukai S, Fukushima M. Efficacy of vitamin D replacement therapy on 28 cases of myalgic encephalomyelitis/chronic fatigue syndrome after COVID-19 vaccination. Nutrition. 2025 Feb 18;134:112718. doi: 10.1016/j.nut.2025.112718. Epub ahead of print. PMID: 40090177. https://www.sciencedirect.com/science/article/pii/S089990072500036X (Full text)

mTORC1 syndrome (TorS): unifying paradigm for PASC, ME/CFS and PAIS

Abstract:

Post-acute SarS-Cov2 (PASC), Myalgia encephalomyelitis/Chronic fatigue syndrome (ME/CFS) and Post-acute infection syndrome (PAIS) consist of chronic post-acute infectious syndromes, sharing exhaustive fatigue, post exertional malaise, intermittent pain, postural tachycardia and neuro-cognitive-psychiatric dysfunction. However, the concerned shared pathophysiology is still unresolved in terms of upstream drivers and transducers. Also, risk factors which may determine vulnerability/progression to the chronic phase still remain to be defined.

In lack of drivers and a cohesive pathophysiology, the concerned syndromes still remain unmet therapeutic needs. ‘mTORC1 Syndrome’ (TorS) implies an exhaustive disease entity driven by sustained hyper-activation of the mammalian target of rapamycin C1 (mTORC1), and resulting in a variety of disease aspects of the Metabolic Syndrome (MetS), non-alcoholic fatty liver disease, chronic obstructive pulmonary disease, some cancers, neurodegeneration and other [Bar-Tana in Trends Endocrinol Metab 34:135-145, 2023]. TorS may offer a cohesive insight of PASC, ME/CFS and PAIS drivers, pathophysiology, vulnerability and treatment options.

Source: Bar-Tana J. mTORC1 syndrome (TorS): unifying paradigm for PASC, ME/CFS and PAIS. J Transl Med. 2025 Mar 10;23(1):297. doi: 10.1186/s12967-025-06220-z. PMID: 40059164. https://translational-medicine.biomedcentral.com/articles/10.1186/s12967-025-06220-z (Full text)

Direct effects of prolonged TNF-α and IL-6 exposure on neural activity in human iPSC-derived neuron-astrocyte co-cultures

Abstract:

Cognitive impairment is one of the many symptoms reported by individuals suffering from long-COVID and other post-viral infection disorders such as myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). A common factor among these conditions is a sustained immune response and increased levels of inflammatory cytokines. Tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) are two such cytokines that are elevated in patients diagnosed with long-COVID and ME/CFS.

In this study, we characterized the changes in neural functionality, secreted cytokine profiles, and gene expression in co-cultures of human iPSC-derived neurons and primary astrocytes in response to prolonged exposure to TNF-α and IL-6. We found that exposure to TNF-α produced both a concentration-independent and concentration-dependent response in neural activity.

Burst duration was significantly reduced within a few days of exposure regardless of concentration (1 pg/mL – 100 ng/mL) but returned to baseline after 7 days. Treatment with low concentrations of TNF-α (e.g., 1 and 25 pg/mL) did not lead to changes in the secreted cytokine profile or gene expression but still resulted in significant changes to electrophysiological features such as interspike interval and burst duration. Conversely, treatment with high concentrations of TNF-α (e.g., 10 and 100 ng/mL) led to reduced spiking activity, which may be correlated to changes in neural health, gene expression, and increases in inflammatory cytokine secretion (e.g., IL-1β, IL-4, and CXCL-10) that were observed at higher TNF-α concentrations.

Prolonged exposure to IL-6 led to changes in bursting features, with significant reduction in the number of spikes in bursts across a wide range of treatment concentrations (i.e., 1 pg/mL-10 ng/mL). In combination, the addition of IL-6 appears to counteract the changes to neural function induced by low concentrations of TNF-α, while at high concentrations of TNF-α the addition of IL-6 had little to no effect. Conversely, the changes to electrophysiological features induced by IL-6 were lost when the cultures were co-stimulated with TNF-α regardless of the concentration, suggesting that TNF-α may play a more pronounced role in altering neural function.

These results indicate that increased concentrations of key inflammatory cytokines associated with long-COVID can directly impact neural function and may be a component of the cognitive impairment associated with long-COVID and other post-viral infection disorders.

Source: Goshi N, Lam D, Bogguri C, George VK, Sebastian A, Cadena J, Leon NF, Hum NR, Weilhammer DR, Fischer NO, Enright HA. Direct effects of prolonged TNF-α and IL-6 exposure on neural activity in human iPSC-derived neuron-astrocyte co-cultures. Front Cell Neurosci. 2025 Feb 12;19:1512591. doi: 10.3389/fncel.2025.1512591. PMID: 40012566; PMCID: PMC11860967. https://pmc.ncbi.nlm.nih.gov/articles/PMC11860967/ (Full text)

Novel Oronasal Drainage for Long COVID: Proposed Mechanisms-Case Report

Abstract:

Long COVID, potentially emerging post COVID-19 infection, involves extreme health challenges. Based on current literature in the field, we propose a novel approach to Long COVID treatment based on epipharyngeal abrasive therapy targeting ostia of the oral and nasal mucosa, having been identified for the first time. The presented case report documents the application of innovative oronasal drainage (OND), a novel treatment integrating physiological, biochemical, and fluid mechanical components simultaneously.

OND led to remarkable improvements and even remissions of various symptoms, along with enhanced hand blood circulation. While the case suggests potential efficacy in Long COVID therapy, acknowledging inherent limitations is essential and its impact needs further validation through clinical trials.

Source: Lorenz C, Frankenberger R. Novel Oronasal Drainage for Long COVID: Proposed Mechanisms-Case Report. Viruses. 2025 Jan 31;17(2):210. doi: 10.3390/v17020210. PMID: 40006965. https://www.mdpi.com/1999-4915/17/2/210 (Full text)

Serum Spike Protein Persistence Post COVID Is Not Associated with ME/CFS

Abstract:

Background/Objectives: According to the World Health Organization (WHO) and Centers for Disease Control and Prevention (CDC), an estimated 3-6% of people suffer from post-COVID condition or syndrome (PCS). A subset meets the diagnostic criteria for myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Studies have reported that SARS-CoV-2 proteins or RNA can persist after acute infection in serum or tissues, but their role in PCS is unclear.

Methods: Here, SARS-CoV-2 spike protein was analyzed in the serum of 121 PCS patients with predominant fatigue and exertional intolerance, of whom 72 met diagnostic criteria for ME/CFS, 37 post-COVID recovered healthy controls, and 32 pre-pandemic healthy controls.

Results: Spike protein was detected in the serum of 11% of recovered controls, 2% of PCS patients, and 14% of ME/CFS patients between 4 and 31 months after SARS-CoV-2 infection, but not in pre-pandemic samples. The occurrence and concentration of spike protein did not correlate with infection or vaccination timepoints. In ME/CFS patients, spike protein presence was not associated with the severity of symptoms or functional disability. In 5 out of 22 patients who under-went immunoglobulin depletion, spike protein levels were reduced or undetectable after treatment, indicating binding to immunoglobulins.

Conclusions: In summary, this study identified serum spike protein in a subset of patients but found no association with ME/CFS.

Source: Fehrer A, Sotzny F, Kim L, Kedor C, Freitag H, Heindrich C, Grabowski P, Babel N, Scheibenbogen C, Wittke K. Serum Spike Protein Persistence Post COVID Is Not Associated with ME/CFS. J Clin Med. 2025 Feb 8;14(4):1086. doi: 10.3390/jcm14041086. PMID: 40004616. https://www.mdpi.com/2077-0383/14/4/1086 (Full text)

Language Matters: What Not to Say to Patients with Long COVID, Myalgic Encephalomyelitis/Chronic Fatigue Syndrome, and Other Complex Chronic Disorders

Abstract:

People with Long COVID, myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), and other complex chronic disorders consistently report having difficulty obtaining effective and compassionate medical care and being disbelieved, judged, gaslighted, and even dismissed by healthcare professionals. We believe that these adversarial interactions and language are more likely to arise when healthcare professionals are confronting complex chronic illnesses without proper training, diagnostic biomarkers, or FDA-approved therapies.
These problematic conversations between practitioners and patients often involve specific words and phrases—termed the “never-words”—can leave patients in significant emotional distress and negatively impact the clinician–patient relationship and recovery. Seeking to prevent these destructive interactions, we review key literature on best practices for difficult clinical conversations and discuss the application of these practices for people with Long COVID, ME/CFS, dysautonomia, and other complex chronic disorders. We provide recommendations for alternative, preferred phrasing to the never-words, which can enhance therapeutic relationship and chronic illness patient care via compassionate, encouraging, and non-judgmental language.
Source: Smyth NJ, Blitshteyn S. Language Matters: What Not to Say to Patients with Long COVID, Myalgic Encephalomyelitis/Chronic Fatigue Syndrome, and Other Complex Chronic Disorders. International Journal of Environmental Research and Public Health. 2025; 22(2):275. https://doi.org/10.3390/ijerph22020275 https://www.mdpi.com/1660-4601/22/2/275 (Full text)

Post-COVID-19 Small Fiber Neuropathy as a New Emerging Quality of Life-Threatening Disease: A Systematic Review

Abstract:

Post-acute sequelae of COVID-19 (PASC) syndrome is considered an emergent and diffuse multidisciplinary problem. Compelling evidence suggests that COVID-19 increases symptoms of pre-existent small fiber neuropathy (SFN) and might trigger de novo onset of SFN. In this systematic review, for the first time, we provide a comprehensive overview of the clinical and diagnostic features of PASC-SFN, including the accompanying disorders, disease evolution, and possible treatments, described in the recent literature.
Following infection, many patients reported a wide range of symptoms and complications, not self-limiting and independent from previous infection severity. SFN begins more frequently with distal limb burning pain and numbness, which accompany other dysautonomia, cognitive, visual, and osteoarticular disorders involving multiple organ systems. In an initial diagnostic suspicion, some tests might be useful as complementary examinations, such as nerve quantitative sensory testing, electromyography, and optic nerve tomography. Otherwise, definite diagnosis is reached with skin biopsy as the gold standard, along with corneal in vivo microscopy when ocular discomfort is present.
Being a long-term condition, multiple and dissimilar symptomatic and disease-modifying drugs were employed for the treatment of this condition with the achievement of partial results, including steroids, pregabalin, gabapentin, duloxetine, vitamins, homotaurine and phosphatidylserine, alpha lipoic acid, immunosuppressants, and intravenous immunoglobulin therapy. PASC-SFN is a complex emerging disease and extremely challenging for physicians. At present, the only feasible management of PASC-SFN is represented by a multidisciplinary tailored approach, with future definitive protocols for diagnosis and treatment deemed essential.
Source: Bandinelli F, Di Carlo M, Colantuono VA, Nozzoli F, Salaffi F, Chiocchetti B, Nucci E, Mastricci A, Gherardi E, Manetti M. Post-COVID-19 Small Fiber Neuropathy as a New Emerging Quality of Life-Threatening Disease: A Systematic Review. Microorganisms. 2025; 13(2):328. https://doi.org/10.3390/microorganisms13020328 https://www.mdpi.com/2076-2607/13/2/328 (Full text)

Exploring DNA methylation, telomere length, mitochondrial DNA, and immune function in patients with Long-COVID

Abstract:

Background: Long-COVID is defined as the persistency or development of new symptoms 3 months after the initial SARS-CoV-2 infection, with these symptoms lasting for at least 2 months with no other explanation. Common persistent symptoms are fatigue, sleep disturbances, post-exertional malaise (PEM), pain, and cognitive problems. Long-COVID is estimated to be present in about 65 million people. We aimed to explore clinical and biological factors that might contribute to Long-COVID.

Methods: Prospective longitudinal cohort study including patients infected with SARS-CoV-2 between March 2020 and March 2022. Patients were assessed between 4 and 12 months after infection at the COVID follow-up clinic at UZ Leuven. We performed a comprehensive clinical assessment (including questionnaires and the 6-min walking test) and biological measures (global DNA methylation, telomere length, mitochondrial DNA copy number, inflammatory cytokines, and serological markers such as C-reactive protein, D-dimer, troponin T).

Results: Of the 358 participants, 328 were hospitalised, of which 130 had severe symptoms requiring intensive care admission; 30 patients were ambulatory referrals. Based on their clinical presentation, we could identify 6 main clusters. One-hundred and twenty-seven patients (35.4%) belonged to at least one cluster. The bigger cluster included PEM, fatigue, sleep disturbances, and pain (n = 57). Troponin T and telomere shortening were the two main markers predicting Long-COVID and PEM-fatigue symptoms.

Conclusions: Long-COVID is not just one entity. Different clinical presentations can be identified. Cardiac involvement (as measured by troponin T levels) and telomere shortening might be a relevant risk factor for developing PEM-fatigue symptoms and deserve further exploring.

Source: Polli A, Godderis L, Martens DS, Patil MS, Hendrix J, Wyns A, Van Campenhout J, Richter E, Fanning L, Vandekerckhove O, Claeys E, Janssens W, Lorent N. Exploring DNA methylation, telomere length, mitochondrial DNA, and immune function in patients with Long-COVID. BMC Med. 2025 Feb 4;23(1):60. doi: 10.1186/s12916-025-03881-x. PMID: 39901177; PMCID: PMC11792217. https://pmc.ncbi.nlm.nih.gov/articles/PMC11792217/ (Full text)