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)

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)

Immunological and Antigenic Signatures Associated with Chronic Illnesses after COVID-19 Vaccination

Summary:

COVID-19 vaccines have prevented millions of COVID-19 deaths. Yet, a small fraction of the population reports a chronic debilitating condition after COVID-19 vaccination, often referred to as post-vaccination syndrome (PVS). To explore potential pathobiological features associated with PVS, we conducted a decentralized, cross-sectional study involving 42 PVS participants and 22 healthy controls enrolled in the Yale LISTEN study.

Compared with controls, PVS participants exhibited differences in immune profiles, including reduced circulating memory and effector CD4 T cells (type 1 and type 2) and an increase in TNFα+ CD8 T cells. PVS participants also had lower anti-spike antibody titers, primarily due to fewer vaccine doses. Serological evidence of recent Epstein-Barr virus (EBV) reactivation was observed more frequently in PVS participants. Further, individuals with PVS exhibited elevated levels of circulating spike protein compared to healthy controls.

These findings reveal potential immune differences in individuals with PVS that merit further investigation to better understand this condition and inform future research into diagnostic and therapeutic approaches.

Source: Bornali Bhattacharjee, Peiwen Lu, Valter Silva Monteiro, Alexandra Tabachnikova, Kexin Wang, William B. Hooper, Victoria Bastos, Kerrie Greene, Mitsuaki Sawano, Christian Guirgis, Tiffany J. Tzeng, Frederick Warner, Pavlina Baevova, Kathy Kamath, Jack Reifert, Danice Hertz, Brianne Dressen, Laura Tabacof, Jamie Wood, Lily Cooke, Mackenzie Doerstling, Shadan Nolasco, Amer Ahmed, Amy Proal, David Putrino, Leying Guan, Harlan M. Krumholz, Akiko Iwasaki. Immunological and Antigenic Signatures Associated with Chronic Illnesses after COVID-19 Vaccination

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)

Distinct pro-inflammatory/pro-angiogenetic signatures distinguish children with Long COVID from controls

Abstract:

Background: Recent proteomic studies have documented that Long COVID in adults is characterized by a pro-inflammatory signature with thromboinflammation. However, if similar events happen also in children with Long COVID has never been investigated.

Methods: We performed an extensive protein analysis of blood plasma from pediatric patients younger than 19 years of age Long COVID and a control group of children with acute COVID-19, MIS-C, and healthy controls resulted similar for sex distribution and age. Children were classified as Long COVID if symptoms persisted for at least 8 weeks since the initial infection, negatively impacted daily life and could not be explained otherwise.

Results: 112 children were included in the study, including 34 children fulfilling clinical criteria of Long COVID, 32 acute SARS-CoV-2 infection, 27 MIS-C and 19 healthy controls. Compared with controls, pediatric Long COVID was characterized by higher expression of the proinflammatory and pro-angiogenetic set of chemokines CXCL11, CXCL1, CXCL5, CXCL6, CXCL8, TNFSF11, OSM, STAMBP1a. A Machine Learning model based on proteomic profile was able to identify LC with an accuracy of 0.93, specificity of 0.86 and sensitivity of 0.97.

Conclusions: Pediatric Long COVID patients have a well distinct blood protein signature marked by increased ongoing general and endothelial inflammation, similarly as happens in adults.

Impact:

  • Pediatric Long COVID has a distinct blood protein signature marked by increased ongoing general and endothelial inflammation.
  • This is the first study studying and documenting proinflammatory profile in blood samples of children with long COVID.
  • Long COVID was characterized by higher expression of the proinflammatory and pro-angiogenetic set of chemokines CXCL11, CXCL1, CXCL5, CXCL6, CXCL8, TNFSF11, OSM, STAMBP1a.
  • A proteomic profile was able to identify Long COVID with an accuracy of 0.93, specificity of 0.86 and sensitivity of 0.97.
  • These findings may inform development of future diagnostic tests.

Source: Buonsenso, D., Cotugno, N., Amodio, D. et al. Distinct pro-inflammatory/pro-angiogenetic signatures distinguish children with Long COVID from controls. Pediatr Res (2025). https://doi.org/10.1038/s41390-025-03837-0  https://www.nature.com/articles/s41390-025-03837-0

Autoantibody-Driven Monocyte Dysfunction in Post-COVID Syndrome with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Abstract:

Post-COVID syndrome (PCS) has emerged as a significant health concern with persisting symptoms. A subset of PCS patients develops severe myalgic encephalomyelitis/chronic fatigue syndrome (pcME/CFS). Dysregulated autoantibodies (AABs) have been implicated in PCS, contributing to immune dysregulation, impairment of autonomous nerve and vascular function. As recently shown in autoimmune diseases, IgG fractions translate disease-specific pathways into various cells. Therefore, we asked whether IgG fractions from PCS patients could be applied in vitro to identify specific cytokine rersponses for PCS patients without (nPCS) and with pcME/CSF.

To assess this, we have stimulated monocyte cell lines with IgG fractions from PCS patients. Our findings reveal distinct patterns of immune regulation by AABs in vascular and immune dysfunction. In contrast to nPCS, pcME/CSF AABs induced enhanced neurotrophic responses, characterized by significant cytokine correlations involving brain-derived neurotrophic factor (BDNF), glial cell-derived neurotrophic factor (GDNF) and LIGHT. AAB-induced cytokine levels correlate with clinical symptoms. Further, this study emphasizes a contribution of AAB in PCS, in mitigating long-term immune dysregulation, and a need for therapies modulating IgG-induced pathways.

Source: Alexander HackelFranziska SotznyElise MennengaHarald HeideckeKai Schulze-FosterKontantinos FourlakisSusanne LuedersHanna GrasshoffKerstin RubarthFrank KonietschkeTanja LangeCarmen ScheibenbogenReza Akbarzade, Gabriela Riemekasten. Autoantibody-Driven Monocyte Dysfunction in Post-COVID Syndrome with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.

Effect of Immunoadsorption on clinical presentation and immune alterations in COVID-19-induced and/or aggravated ME/CFS

Abstract:

Autoreactive antibodies (AAB) are currently being investigated as causative or aggravating factors during post-COVID. In this study we analyze the effect of immunoadsorption therapy on symptom improvement and the relationship with immunological parameters in post-COVID patients exhibiting symptoms of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) induced or aggravated by an SARS-CoV-2 infection. This observational study includes 12 post-COVID patients exhibiting a predominance of ME/CFS symptoms alongside increased concentrations of autonomic nervous system receptors (ANSR) autoantibodies and neurological impairments.

We found that following immunoadsorption therapy, the ANSR autoantibodies were nearly eliminated from the patients’ blood. The removal of IgG antibodies was accompanied by a decrease of pro-inflammatory cytokines including IL4, IL2, IL1β, TNF and IL17A serum levels, and a significant reduction of soluble spike protein. Notably, a strong positive correlation between pro-inflammatory cytokines and ASNR-AABs β1, β2, M3, and M4 was observed in spike protein-positive patients, whereas no such correlation was evident in spike protein-negative patients.

30 days post-immunoadsorption therapy, patients exhibited notable improvement in neuropsychological function and a modest but statistically significant amelioration of hand grip strength was observed. However, neither self-reported symptoms nor scores on ME/CFS questionnaires showed a significant improvement and a rebound of the removed proteins occurring within a month.

Source: Anft M, Wiemers L, Rosiewicz KS, Doevelaar A, Skrzypczyk S, Kurek J, Kaliszczyk S, Seidel M, Stervbo U, Seibert FS, Westhoff TH, Babel N. Effect of Immunoadsorption on clinical presentation and immune alterations in COVID-19-induced and/or aggravated ME/CFS. Mol Ther. 2025 Jan 9:S1525-0016(25)00011-5. doi: 10.1016/j.ymthe.2025.01.007. Epub ahead of print. PMID: 39797400. https://www.cell.com/molecular-therapy-family/molecular-therapy/pdf/S1525-0016(25)00011-5.pdf (Full text) https://pubmed.ncbi.nlm.nih.gov/39797400/ (Abstract)

Incidence and Prevalence of Post-COVID-19 Myalgic Encephalomyelitis: A Report from the Observational RECOVER-Adult Study

Abstract:

Background: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) may occur after infection. How often people develop ME/CFS after SARS-CoV-2 infection is unknown.

Objective: To determine the incidence and prevalence of post-COVID-19 ME/CFS among adults enrolled in the Researching COVID to Enhance Recovery (RECOVER-Adult) study.

Design, setting, and participants: RECOVER-Adult is a longitudinal observational cohort study conducted across the U.S. We included participants who had a study visit at least 6 months after infection and had no pre-existing ME/CFS, grouped as (1) acute infected, enrolled within 30 days of infection or enrolled as uninfected who became infected (n=4515); (2) post-acute infected, enrolled greater than 30 days after infection (n=7270); and (3) uninfected (1439).

Measurements: Incidence rate and prevalence of post-COVID-19 ME/CFS based on the 2015 Institute of Medicine ME/CFS clinical diagnostic criteria.

Results: The incidence rate of ME/CFS in participants followed from time of SARS-CoV-2 infection was 2.66 (95% CI 2.63-2.70) per 100 person-years while the rate in matched uninfected participants was 0.93 (95% CI 0.91-10.95) per 100 person-years: a hazard ratio of 4.93 (95% CI 3.62-6.71). The proportion of all RECOVER-Adult participants that met criteria for ME/CFS following SARS-CoV-2 infection was 4.5% (531 of 11,785) compared to 0.6% (9 of 1439) in uninfected participants. Post-exertional malaise was the most common ME/CFS symptom in infected participants (24.0%, 2830 of 11,785). Most participants with post-COVID-19 ME/CFS also met RECOVER criteria for long COVID (88.7%, 471 of 531).

Limitations: The ME/CFS clinical diagnostic criteria uses self-reported symptoms. Symptoms can wax and wane.

Conclusion: ME/CFS is a diagnosable sequela that develops at an increased rate following SARS-CoV-2 infection. RECOVER provides an unprecedented opportunity to study post-COVID-19 ME/CFS.

Source: Vernon SD, Zheng T, Do H, Marconi VC, Jason LA, Singer NG, Natelson BH, Sherif ZA, Bonilla HF, Taylor E, Mullington JM, Ashktorab H, Laiyemo AO, Brim H, Patterson TF, Akintonwa TT, Sekar A, Peluso MJ, Maniar N, Bateman L, Horwitz LI, Hess R; NIH Researching COVID to Enhance Recovery (RECOVER) Consortium. Incidence and Prevalence of Post-COVID-19 Myalgic Encephalomyelitis: A Report from the Observational RECOVER-Adult Study. J Gen Intern Med. 2025 Jan 13. doi: 10.1007/s11606-024-09290-9. Epub ahead of print. PMID: 39804551. https://link.springer.com/article/10.1007/s11606-024-09290-9 (Full text)

Cluster analysis to identify long COVID phenotypes using 129Xe magnetic resonance imaging: a multicentre evaluation

Abstract:

Background: Long COVID impacts ∼10% of people diagnosed with coronavirus disease 2019 (COVID-19), yet the pathophysiology driving ongoing symptoms is poorly understood. We hypothesised that 129Xe magnetic resonance imaging (MRI) could identify unique pulmonary phenotypic subgroups of long COVID. Therefore, we evaluated ventilation and gas exchange measurements with cluster analysis to generate imaging-based phenotypes.

Methods: COVID-negative controls and participants who previously tested positive for COVID-19 underwent 129Xe MRI ∼14 months post-acute infection across three centres. Long COVID was defined as persistent dyspnoea, chest tightness, cough, fatigue, nausea and/or loss of taste/smell at MRI; participants reporting no symptoms were considered fully recovered. 129Xe MRI ventilation defect percent (VDP) and membrane-to-gas (Mem/Gas), red blood cell-to-membrane (RBC/Mem) and red blood cell-to-gas (RBC/Gas) ratios were used in k-means clustering for long COVID, and measurements were compared using ANOVA with post-hoc Bonferroni correction.

Results: We evaluated 135 participants across three centres: 28 COVID-negative (mean±sd age 40±16 years), 34 fully recovered (42±14 years) and 73 long COVID (49±13 years). RBC/Mem (p=0.03) and forced expiratory volume in 1 s (FEV1) (p=0.04) were different between long COVID and COVID-negative; FEV1 and all other pulmonary function tests (PFTs) were within normal ranges. Four unique long COVID clusters were identified compared with recovered and COVID-negative. Cluster 1 was the youngest with normal MRI and mild gas trapping; Cluster 2 was the oldest, characterised by reduced RBC/Mem but normal PFTs; Cluster 3 had mildly increased Mem/Gas with normal PFTs; and Cluster 4 had markedly increased Mem/Gas with concomitant reduction in RBC/Mem and restrictive PFT pattern.

Conclusions: We identified four 129Xe MRI long COVID phenotypes with distinct characteristics. 129Xe MRI can dissect pathophysiological heterogeneity of long COVID to enable personalised patient care.

Source: Eddy RL, Mummy D, Zhang S, Dai H, Bechtel A, Schmidt A, Frizzell B, Gerayeli FV, Leipsic JA, Leung JM, Driehuys B, Que LG, Castro M, Sin DD, Niedbalski PJ. Cluster analysis to identify long COVID phenotypes using 129Xe magnetic resonance imaging: a multicentre evaluation. Eur Respir J. 2024 Mar 28;63(3):2302301. doi: 10.1183/13993003.02301-2023. PMID: 38331459; PMCID: PMC10973687. https://pmc.ncbi.nlm.nih.gov/articles/PMC10973687/ (Full text)

More than “Brain Fog”: Cognitive Dysfunction and the Role of Occupational Therapy in Long COVID

Abstract:

Long COVID is a disabling condition which affects occupational performance and quality of life. It interferes with activities of daily living, work, and many meaningful life roles. Cognitive dysfunction is a frequently reported symptom, yet it is commonly overlooked. It is important that cognitive activity is considered when working with people with long COVID, particularly when identifying triggers of post exertional symptom exacerbation. There are many potential mechanisms that could be driving cognitive dysfunction in long COVID including neuroinflammation, viral persistence, vascular damage, and orthostatic intolerance. It is important to consider these to help guide intervention.

The purpose of this clinical perspective is to highlight the debilitating impact of cognitive dysfunction in those with long COVID and share the key role of occupational therapists in this area. Cognitive dysfunction may be missed on standardized assessments as they may not be sensitive enough due to the episodic nature of symptoms. Occupational therapists can play a key role in this area as they are experts in assessing occupational performance and in providing safe cognitive assessment and rehabilitation.

Source: Skiffington, Helen OT, BSc Hons1,2; Breen, Ciara MSc, HCM3,4,5. More than “Brain Fog”: Cognitive Dysfunction and the Role of Occupational Therapy in Long COVID. Cardiopulmonary Physical Therapy Journal 36(1):p 39-49, January 2025. | DOI: 10.1097/CPT.0000000000000274 https://journals.lww.com/cptj/fulltext/2025/01000/more_than__brain_fog___cognitive_dysfunction_and.7.aspx (Full text)