Distinguishing features of long COVID identified through immune profiling.

Post-acute infection syndromes may develop after acute viral disease1. Infection with SARS-CoV-2 can result in the development of a post-acute infection syndrome known as long COVID. Individuals with long COVID frequently report unremitting fatigue, post-exertional malaise, and a variety of cognitive and autonomic dysfunctions2-4. However, the biological processes that are associated with the development and persistence of these symptoms are unclear. Here 275 individuals with or without long COVID were enrolled in a cross-sectional study that included multidimensional immune phenotyping and unbiased machine learning methods to identify biological features associated with long COVID. Marked differences were noted in circulating myeloid and lymphocyte populations relative to the matched controls, as well as evidence of exaggerated humoral responses directed against SARS-CoV-2 among participants with long COVID. Furthermore, higher antibody responses directed against non-SARS-CoV-2 viral pathogens were observed among individuals with long COVID, particularly Epstein-Barr virus. Levels of soluble immune mediators and hormones varied among groups, with cortisol levels being lower among participants with long COVID. Integration of immune phenotyping data into unbiased machine learning models identified the key features that are most strongly associated with long COVID status. Collectively, these findings may help to guide future studies into the pathobiology of long COVID and help with developing relevant biomarkers.

Long COVID or Post-Acute Sequelae of SARS-CoV-2 Infection (PASC) and the Urgent Need to Identify Diagnostic Biomarkers and Risk Factors.

Long COVID, or post-acute sequelae of SARS-CoV-2 infection (PASC), also known as post-COVID-19 condition or post-COVID syndrome, can affect anyone infected with SARS-CoV-2, regardless of age or the severity of the initial symptoms of COVID-19. Long COVID/PASC is the continuation or development of new symptoms after three months from the initial SARS-CoV-2 infection, which lasts for at least two months and has no other identifiable cause. Long COVID/PASC occurs in 10-20% of patients infected with SARS-CoV-2. The most common symptoms include fatigue, cognitive impairment (brain fog), and shortness of breath. However, more than 200 symptoms have been reported. No phenotypic or diagnostic biomarkers have been identified for developing long COVID/PASC, which is a multisystem disorder that can present with isolated or combined respiratory, hematological, immunological, cardiovascular, and neuropsychiatric symptoms. There is no cure. Therefore, individualized patient management requires a multidisciplinary clinical approach. Because millions of people have had and continue to have COVID-19, even in the era of vaccination and antiviral therapies, long COVID/PASC is now and will increasingly become a health and economic burden that the world must prepare for. Almost five years from the beginning of the COVID-19 pandemic, this article aims to review what is currently known about long COVID/PASC, the anticipated increasing global health burden, and why there is still an urgent need to identify diagnostic biomarkers and risk factors to improve prevention and treatment.

Applicability of heart rate variability for cardiac autonomic assessment in long-term COVID patients: A systematic review.

PURPOSE: To carry out a systematic review to determine the main methods used to study the heart rate variability (HRV) in individuals after the acute phase of COVID-19. METHODS: The study followed the Preferred Items for Reporting for Systematic Reviews and Meta-Analyses (PRISMA) statement. PubMed, Web of Science, Scopus and CINAHAL electronic databases were searched from the inception to November 2022. The studies were included if they used HRV assessment based on linear and non-linear methods in long-term COVID-19 patients. Review studies, theses and dissertations, conference abstracts, longitudinal studies, studies conducted on animals and studies that included individuals in the acute phase of the COVID-19 were excluded. The methodological quality of the studies was analyzed using the Joanna Briggs Institute's critical evaluation checklist for cross-sectional analytical studies. RESULTS: HRV was mainly assessed using 24-h Holter monitoring in 41.6% (5/12) of the studies, and 12­lead ECG was used in 33.3% (4/12). Regarding the type of assessment, 66.6% (8/12) of the studies only used linear analysis, where 25% (3/12) used analysis in the time domain, and 41.6% (5/12) used both types. Non-linear methods were combined with the previously cited linear method in 25% (3/12) of the studies. Moreover, 50% (6/12) of the studies demonstrated post-COVID-19 autonomic dysfunction, with an increase in the predominance of cardiac sympathetic modulation. The average score of the evaluation checklist was 6.6, characterized as having reasonable methodological quality. CONCLUSION: 24-h Holter and 12­lead ECG are considered effective tools to assess HRV in post-COVID-19 patients. Furthermore, the findings reveal diverse effects of COVID-19 on the autonomic nervous system's sympathovagal balance, which might be influenced by secondary factors such as disease severity, patients' overall health, evaluation timing, post-infection complications, ventilatory functions, and age.

Persistent Circulating Severe Acute Respiratory Syndrome Coronavirus 2 Spike Is Associated With Post-acute Coronavirus Disease 2019 Sequelae.

The diagnosis of postacute sequelae of coronavirus disease 2019 (PASC) poses an ongoing medical challenge. To identify biomarkers associated with PASC we analyzed plasma samples collected from PASC and coronavirus disease 2019 patients to quantify viral antigens and inflammatory markers. We detect severe acute respiratory syndrome coronavirus 2 spike predominantly in PASC patients up to 12 months after diagnosis.

Liquid biomarkers of macrophage dysregulation and circulating spike protein illustrate the biological heterogeneity in patients with post-acute sequelae of COVID-19.

Post-acute sequelae of COVID-19 (PASC) are long-term consequences of SARS-CoV-2 infection that can substantially impair the quality of life. Underlying mechanisms ranging from persistent viruses to innate and adaptive immune dysregulation have been discussed. Here, we profiled the plasma of 181 individuals from the cohort study for digital health research in Germany (DigiHero), including individuals after mild to moderate COVID-19 with or without PASC and uninfected controls. We focused on soluble factors related to monocyte/macrophage biology and on circulating SARS-CoV-2 spike (S1) protein as a potential biomarker for persistent viral reservoirs. At a median time of 8 months after infection, we found pronounced dysregulation in almost all tested soluble factors, including both pro-inflammatory and pro-fibrotic cytokines. These immunological perturbations were remarkably independent of ongoing PASC symptoms per se, but further correlation and regression analyses suggested PASC-specific patterns involving CCL2/MCP-1 and IL-8 that either correlated with sCD162, sCD206/MMR, IFN-α2, IL-17A and IL-33, or IL-18 and IL-23. None of the analyzed factors correlated with the detectability or levels of circulating S1, indicating that this represents an independent subset of patients with PASC. These data confirm prior evidence of immune dysregulation and persistence of viral protein in PASC and illustrate its biological heterogeneity that still awaits correlation with clinically defined PASC subtypes.

Emerging research on postacute COVID-19 complications.

ABSTRACT: An estimated 21.5% of patients in the United States who have had COVID-19 report development of a prolonged postviral syndrome that has been called postacute sequelae of COVID-19 (PASC). Symptoms can range from very mild to debilitating damage to organ systems caused directly by the virus and indirectly by the body's inflammatory response. Research into defining PASC and discovering effective treatments is ongoing. This article discusses the common presentations of PASC in patients who have had COVID-19; describes specific effects on the pulmonary, cardiovascular, and central nervous systems; and identifies potential treatments based on current literature.

How Primary Care Physicians Can Recognize and Treat Long COVID.

This Medical News article discusses challenges to treatment of post­COVID-19 condition in primary care.

Effects of rehabilitation interventions for old adults with long COVID: A systematic review and meta-analysis of randomised controlled trials.

Background: There is limited evidence on the effectiveness of the existing rehabilitation interventions for old adults with long coronavirus disease (COVID), which is of particular concern among old adults. Methods: We systematically searched studies published in PubMed, EMBASE, Web of Science, Scopus, and Cochrane Library databases from their inception to 15 November 2023. Randomised controlled trials (RCTs) compared rehabilitation interventions with other controls in old adults (mean/median age of 60 or older) with long COVID were included. We performed a meta-analysis to compare the effects of the rehabilitation interventions with the common control group. Mean difference (MD) or standardised mean difference (SMD) with its 95% confidence intervals (CI) were used as summary statistics. Moreover, subgroup analyses based on the intervention programmes, the severity of acute infection, and the age of participants were carried out. Results: A total of 11 RCTs involving 832 participants (64.37 ± 7.94 years, 52.2% were men) were included in the analysis. Compared with the control groups, rehabilitation interventions significantly improved 6-minute walking test (6 MWT; MD = 15.77 metres (m), 95% CI = 5.40, 26.13, P < 0.01), 30-second sit-to-stand test (MD = 4.11 number of stands (n), 95% CI = 2.46, 5.76, P < 0.001), all aspects of quality of life, independence in activities of daily living (SMD = 0.31, 95% CI = 0.14, 0.48, P < 0.001), and relieved fatigue (SMD = -0.66, 95% CI = -1.13, -0.19, P < 0.01), depression (SMD = -0.89, 95% CI = -1.76, -0.02, P < 0.05) and anxiety (SMD = -0.81, 95% CI = -1.58, -0.05, P < 0.05). However, the improvement of hand grip strength and pulmonary function was not statistically significant (P > 0.05). Subgroup analyses showed that improvements in 6 MWT, fatigue, anxiety, and depression were more pronounced in old patients who received exercise training, while those who received respiratory rehabilitation had more pronounced improvements in pulmonary function and quality of life. Conclusions: Old adults with long COVID who underwent rehabilitation interventions experienced significant improvement in functional capacity, fatigue, quality of life, independence in activities of daily living, and mental health outcomes compared with usual/standard care. These findings suggest that screening, management, and rehabilitation interventions for long COVID in older adults should be strengthened to improve their complete health status and functional status, thereby reducing the long-term disease burden caused by long COVID and fostering healthy aging during the post-pandemic era.

Developing effective strategies to optimize physical activity and cardiorespiratory fitness in the long Covid population- The need for caution and objective assessment.

The Post Covid-19 Condition (commonly known as Long Covid) has been defined by the World Health Organisation as occurring in individuals with a history of probable or confirmed SARS CoV 2 infection, usually within 3 months from the onset of acute Covid-19 infection with symptoms that last for at least two months which cannot be explained by an alternative diagnosis. Long Covid is associated with over two hundred recognised symptoms and affects tens of millions of people worldwide. Widely reported reductions in quality of life(QoL) and functional status are caused by extremely sensitive and cyclical symptom profiles that are augmented following exposure to physical, emotional, orthostatic, and cognitive stimuli. This manifestation prevents millions of people from engaging in routine activities of daily living (ADLs) and has important health and well-being, social and economic impacts. Post-exertional symptom exacerbation (PESE) (also known as post-exertional malaise) is an exacerbation in the severity of fatigue and other symptoms following physical, emotional, orthostatic and cognitive tasks. Typically, this will occur 24-72 h after "over-exertion" and can persist for several days and even weeks. It is a hallmark symptom of Long Covid with a reported prevalence of 86%. The debilitating nature of PESE prevents patients from engaging in physical activity which impacts functional status and QoL. In this review, the authors present an update to the literature relating to PESE in Long Covid and make the case for evidence-based guidelines that support the design and implementation of safe rehabilitation approaches for people with Long Covid. This review also considers the role of objective monitoring to quantify a patient's response to external stimuli which can be used to support the safe management of Long Covid and inform decisions relating to engagement with any stimuli that could prompt an exacerbation of symptoms.

Post-COVID Trajectory of Pentraxin 3 Plasma Levels Over 6 Months and Their Association with the Risk of Developing Post-Acute Depression and Anxiety.

BACKGROUND AND OBJECTIVES: Clinical manifestations of coronavirus disease 2019 (COVID-19) often persist after acute disease resolution. Underlying molecular mechanisms are unclear. The objective of this original article was to longitudinally measure plasma levels of markers of the innate immune response to investigate whether they associate with and predict post-COVID symptomatology. METHODS: Adult patients with previous severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection during the first pandemic wave who underwent the 6-month multidisciplinary follow-up were included. Plasma levels of pentraxin 3 (PTX3), the complement components C3a and C5a, and chitinase-3 like-protein-1 (CHI3L1) were measured at hospital admission during acute disease (baseline) and at 1 and 6 months after hospital discharge. Associations with post-COVID-19 sequelae at 6 months were investigated using descriptive statistic and multiple regression models. RESULTS: Ninety-four COVID-19 patients were included. Baseline PTX3, C5a, C3a, and CHI3L1 did not predict post-COVID-19 sequelae. The extent of the reduction of PTX3 over time (delta PTX3) was associated with lower depressive and anxiety symptoms at 6 months (both p < 0.05). When entering sex, age, need for intensive care unit or non-invasive ventilation during hospital stay, psychiatric history, and baseline PTX3 as nuisance covariates into a generalized linear model (GLM), the difference between baseline and 6-month PTX3 levels (delta PTX3) significantly predicted depression (χ2 = 4.66, p = 0.031) and anxiety (χ2 = 4.68, p = 0.031) at 6 months. No differences in PTX3 levels or PTX3 delta were found in patients with or without persistent or new-onset other COVID-19 symptoms or signs at 6 months. Plasma levels of C3a, C5a, and CHI3L1 did not correlate with PTX3 levels at either time point and failed to associate with residual or de novo respiratory or systemic clinical manifestations of the disease at 6 months. CONCLUSIONS: A lower reduction of plasma PTX3 after acute COVID-19 associates with the presence of depression and anxiety, suggesting an involvement of inflammation in post-COVID-19 psychopathology and a potential role of PTX3 as a biomarker.

[Proposal for a diagnostic approach to long COVID]. / Propuesta de abordaje diagnóstico del COVID persistente.

The objective of this communication is to provide a proposal for a diagnostic approach to persistent COVID based on the various current etiopathogenic theories and to serve as a guide on how to start the diagnostic process in a patient affected by this syndrome according to the prevailing symptomatology and the basic studies and of extension that can be requested and even assisted by commercial kits that would help a better diagnosis.

La presente comunicación tiene como objetivo aportar una propuesta de abordaje diagnóstico del COVID persistente con base en las diversas teorías etiopatogénicas actuales, así como servir de guía para iniciar el proceso diagnóstico en un paciente afectado por este síndrome, acorde a la sintomatología prevaleciente y a los estudios básicos y de extensión que se pueden solicitar, e incluso auxiliados por pruebas comerciales que ayudarían a un mejor diagnóstico.

Swiss recommendations for the diagnosis, management and follow-up of post-COVID condition in primary care medicine (2023).

No abstract available.