Pathogenic mechanisms of post-acute sequelae of SARS-CoV-2 infection (PASC)

Translating animal models of SARS-CoV-2 infection to vascular, neurological and gastrointestinal manifestations of COVID-19

Since the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) initiated a global pandemic resulting in an estimated 775 million infections with over 7 million deaths, it has become evident that COVID-19 is not solely a pulmonary disease. Emerging evidence has shown that, in a subset of patients, certain symptoms - including chest pain, stroke, anosmia, dysgeusia, diarrhea and abdominal pain - all indicate a role of vascular, neurological and gastrointestinal (GI) pathology in the disease process. Many of these disease processes persist long after the acute disease has been resolved, resulting in 'long COVID' or post-acute sequelae of COVID-19 (PASC). The molecular mechanisms underlying the acute and systemic conditions associated with COVID-19 remain incompletely defined. Appropriate animal models provide a method of understanding underlying disease mechanisms at the system level through the study of disease progression, tissue pathology, immune system response to the pathogen and behavioral responses. However, very few studies have addressed PASC and whether existing models hold promise for studying this challenging problem. Here, we review the current literature on cardiovascular, neurological and GI pathobiology caused by COVID-19 in patients, along with established animal models of the acute disease manifestations and their prospects for use in PASC studies. Our aim is to provide guidance for the selection of appropriate models in order to recapitulate certain aspects of the disease to enhance the translatability of mechanistic studies.

NETosis: A key player in autoimmunity, COVID-19, and long COVID

NETosis, the process through which neutrophils release neutrophil extracellular traps (NETs), has emerged as a crucial mechanism in host defense and the pathogenesis of autoimmune responses. During the SARS-CoV-2 pandemic, this process received significant attention due to the central role of neutrophil recruitment and activation in infection control. However, elevated neutrophil levels and dysregulated NET formation have been linked to coagulopathy and endothelial damage, correlating with disease severity and poor prognosis in COVID-19. Moreover, it is known that SARS-CoV-2 can induce persistent low-grade systemic inflammation, known as long COVID, although the underlying causes remain unclear. It has been increasingly acknowledged that excessive NETosis and NET generation contribute to further pathophysiological abnormalities following SARS-CoV-2 infection. This review provides an updated overview of the role of NETosis in autoimmune diseases, but also the relationship between COVID-19 and long COVID with autoimmunity (e.g., latent and overt autoimmunity, molecular mimicry, epitope spreading) and NETosis (e.g., immune responses, NET markers). Finally, we discuss potential therapeutic strategies targeting dysregulated NETosis to mitigate the severe complications of COVID-19 and long COVID.

Nanoparticle-mediated sodium butyrate delivery for repairing hypoxic-ischemic brain injury in premature infants

Hypoxic-ischemic encephalopathy of prematurity (HIEP) is a leading cause of acute mortality and chronic neurological injury in premature infants. This study investigates the molecular mechanisms by which magnetic fluorescent nanoparticles loaded with sodium butyrate (MNs@SB) repair HIEP by modulating the Sp1 and TGF-β1 signaling pathways. Untargeted metabolomics analysis revealed significant suppression of the butyrate metabolism pathway in the intestinal tissues of HIEP mice. We synthesized and characterized MNs@SB nanoparticles, with zeta potential and DLS results indicating an average nanoparticle size of approximately 79.89 nm and a zeta potential of -36.87 mV. TEM images confirmed that the nanoparticles formed polymer-coated clusters. MNs@SB demonstrated excellent biocompatibility and stable magnetic targeting behavior. The nanoparticles were delivered to the brain via tail vein injection and magnetic targeting, with focused ultrasound facilitating their diffusion. The results showed that HIEP mice exhibited a significant increase in infarct size and extensive tissue loss, whereas MNs@SB treatment effectively reversed HIEP-induced brain damage, improving both short-term and long-term neurological deficits. Single-cell RNA sequencing and high-throughput transcriptome analysis revealed that MNs@SB promoted brain repair by upregulating neuronal Sp1, activating the TGF-β1 signaling pathway, and inhibiting neuronal apoptosis. In vivo experiments further confirmed that MNs@SB treatment restored SP1 mRNA and protein expression in the brain. Additionally, MNs@SB treatment significantly restored TGF-β1, p-SMAD2, and p-SMAD3 protein expression, indicating activation of the TGF-β1/SMAD2/3 signaling pathway. This study presents a novel nanomedicine therapeutic strategy with potential clinical applications.

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

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.

Symptoms and pathophysiology of post-acute sequelae following COVID-19 (PASC): a cohort study

BACKGROUND

Several studies reported long-term consequences of severe COVID-19. However, pathophysiological mechanisms of Post-Acute Sequelae following COVID-19 (PASC) in patients with mild acute COVID-19 have been less investigated. Specifically, the link between PASC and immuno-inflammatory abnormalities is inconsistent in the literature. The hypothesis that different pathophysiological mechanisms could explain the persistent symptoms needs to be explored.

METHODS

The COPER cohort is a prospective study that included participants with PASC and with a history of COVID-19 without persistent symptoms. None were hospitalised for COVID-19. Participants underwent two home visits six months apart for biological sample collection and completed questionnaires on medical history, infection, vaccination, symptoms, and mental health. The study analysed association between persistent symptoms and 14 blood biomarkers, comparing participants with PASC with recovered participants.

FINDINGS

Between June and November 2022, 1000 participants were included in the study, 199 were excluded due to missing data or sample (35), SARS-CoV-2 infection less than 3 months (36) or lack of known SARS-CoV-2 infection and negative serology (128), with two groups analysed: recovered (n = 490), PASC (n = 311). Participants with PASC were more frequently women, had a higher BMI and a median number of 3 persistent symptoms, with common symptoms being asthenia, dyspnoea, cough, and sleep disorders. Biological analysis revealed significant associations between certain PACS symptoms and biomarkers of viral activation (IFNγ, IP-10), COVID-19 severity (CD163) and vascular activation (VCAM-1, ICAM-1), mainly in subjects whose symptoms had lasted less than a year. However, these associations did not persist over time.

INTERPRETATION

The results suggest a polymorphic and dynamic pathophysiology according to symptoms and time since infection. Other hypotheses, beyond those related to persistent inflammation, should be explored.

FUNDING

French Ministry of Health and Prevention and the French Ministry of Higher Education, Research and Innovation.

Causal relationship between immune cells and post-viral fatigue syndrome: a Mendelian randomization study

BACKGROUND

Accumulating evidence has hinted at a correlation between immune cells and post-viral fatigue syndrome (PVFS). However, it is still ambiguous whether these associations indicate a causal connection.

OBJECTIVE

To elucidate the potential causal link between immune cells and PVFS, we performed a two-sample Mendelian randomization (MR) study.

METHODS

We obtained summary data on PVFS cases (Ncase = 195) and controls (Ncontrol = 382,198) from the FinnGen consortium. Additionally, we retrieved comprehensive statistical information on 731 immune cell features. Our analysis encompassed both forward and reverse MR approaches. To ensure the reliability and validity of our findings, we conducted rigorous sensitivity analyses, addressing issues of robustness and heterogeneity.

RESULT

Our study presents compelling evidence of a probable causal link between immune cells and PVFS. Notably, we have pinpointed 28 distinct types of immune cell traits that potentially exhibit a causal association with PVFS. Among a pool of 7 31 immune cell traits, we identified 28 immune cell types that exhibited a potential causal association with PVFS. These included 9 B cells, 1 conventional dendritic cell (cDC), 1 maturation stage of T cell, 3 myeloid cells, 9 T, B, NK, and monocyte cells (TBNK), and 5 regulatory T cells (Treg).

CONCLUSION

Through genetic analyses, our study has unveiled profound causal connections between specific types of immune cells and PVFS, offering valuable guidance for forthcoming clinical investigations.

Elevated amputation rates in COVID-19 survivors: Insights from a large-scale Japanese cohort study

OBJECTIVE

COVID-19 has been linked to increased vascular complications, but its long-term impact on amputation rates is unclear. This study evaluated amputation risk post-COVID-19 using a nationwide insurance claims database in Japan.

METHODS

We conducted a retrospective cohort study using data from the National Database of Health Insurance Claims and Specific Health Checkups of Japan. COVID-19 cases were identified via insurance payment waivers, and amputations were defined by procedure codes. Propensity score matching created balanced cohorts of COVID-19 exposed and unexposed individuals. Matched cohorts were compared for amputation incidence, calculating incidence rate ratios (IRRs), and differences (IRDs). Sensitivity analyses examined outcomes at different time points, and subgroup analyses stratified results by key characteristics.

RESULTS

This study included 3,098,948 matched pairs. Over a median follow-up of 7 months, 286 amputations occurred in the COVID-19 group vs 123 in controls (IRR 2.33, 95% CI 1.88-2.90; IRD 5.57 per 1,000,000 person-months, 95% CI 4.22-6.92). The elevated risk persisted beyond 2 years post infection (IRR 2.03, 95% CI 1.31-3.20). Subgroup analyses showed higher risks in individuals with higher comorbidity burden (Charlson Comorbidity Index [CCI] ≥2; IRR 2.45 95% CI 1.92, 2.79) vs lower comorbidity burden (CCI 0-1; IRR 0.71 95%CI 0.29, 1.71) with significant interaction (P = 0.04).

CONCLUSIONS

Amputation rates increased among COVID-19 survivors, persisting for over 2 years post infection. The interaction between COVID-19 and comorbidity burden highlights the need for vigilant long-term monitoring and management of vascular complications in COVID-19 survivors, particularly those with multiple comorbidities.

The role of DAMP cytotoxic fractions in the immune markers' disruption in patients with urgent surgical pathology and against the background of post-COVID-19 syndrome

BACKGROUND

As a result of the SARS-CoV-2 pandemic, various population groups were formed that had acute and asymptomatic COVID-19. A survey in these groups revealed with equal frequency an asthenic symptom complex, the so-called post-COVID-19 syndrome (PCS). The frequency of urgent surgical pathology against the background of PCS and structural and functional disorders of various organs was increased. The aim - to study the dynamics of immunoresistance factors changes in patients with urgent surgical pathology that developed against the background of PCS and to identify pathogenic markers of the severe course and the risk of mortality.

MATERIALS AND METHODS

To examine patients with PCS and urgent cardiovascular (n = 103) and abdominal (n = 106) pathology we used the following methods: fluorescence microscopy, confocal microscopy, flow cytometry, spectrophotometry, ELISA.

RESULTS

We revealed a temporal dependence of immune dysfunction in patients with a comorbid course of urgent surgical pathology and PCS. The nature of the DAMP (damage-associated molecular patterns) cytotoxic fractions ratio was associated with certain changes in innate and adaptive immunity factors, severity of the condition and risk of mortality. At the first stage (2020-2021), patients with PCS has disorders of the humoral and cellular components of innate immunity against the background of an increase in the oligopeptide and peptide DAMP fractions. At the second stage (2022-2024) of PCS development, changes in innate as well as adaptive immunity were observed against the background of an increase in the cytotoxic oligonucleotide DAMP fraction (mortality was 17.3%).

CONCLUSIONS

The identified markers of impaired immunoresistance in cardiovascular and abdominal urgent pathology can be used to select targeted therapy tactics.

Investigating the profile of patients with idiopathic inflammatory myopathies in the post-COVID-19 period

The 2019 coronavirus disease (COVID-19) pandemic has changed the characteristics of many diseases. It remains unclear whether idiopathic inflammatory myopathies (IIMs) exhibit distinct phenotypes in the context of COVID-19. This retrospective study analyzed patients with IIMs admitted to West China Hospital from January 2022 to December 2023. Among them, 171 had a history of COVID-19 (prior COVID-19 [PC]), while 121 did not (no prior COVID-19 [NPC]). Medical histories, lab tests, and echocardiography data were compared. The PC group exhibited a greater incidence of cardiac damage, including a greater proportion of cardiac injury (P = 0.016), clinical diagnosis of myocarditis (P = 0.02), palpitation (P = 0.031), and Myositis Activity Assessment Visual Analog Scale/Myositis Intention-to-Treat Activity Index cardiovascular involvement scores (all P < 0.001), and elevated levels of myoglobin (P = 0.03), creatinine kinase MB (P = 0.015), cardiac troponin T (P = 0.011), N-terminal pro-B-type natriuretic peptide (P = 0.028), lactate dehydrogenase (P = 0.033), and hydroxybutyrate dehydrogenase (P = 0.019). Echocardiographic analysis revealed a greater diameter of the left atrium (P = 0.040), left ventricle (P = 0.013), greater end-diastolic dimension (P = 0.042), and greater end-diastolic volume (P = 0.036) in the PC group than in the NPC group. Transcriptional data analysis based on public databases indicated that various mechanisms, including collagen matrix proliferation, calcium ion pathway regulation, oxidative stress, cell proliferation, and inflammatory molecules, collectively contribute to the pathogenesis of myocardial damage in patients with IIMs and COVID-19. The study serves as a crucial reminder for clinicians to remain vigilant regarding the enduring cardiovascular consequences associated with IIMs after COVID-19.

IMPORTANCE

This study systematically analyzed the clinical features, laboratory test results, and echocardiographic findings of patients with IIMs, comparing those with and without a history of COVID-19 infection. The analysis revealed significant alterations in the clinical manifestations of IIM patients after COVID-19, particularly in relation to cardiac involvement. Our findings highlight the crucial importance for clinicians to maintain vigilance concerning the potential long-term cardiovascular sequelae associated with IIMs in post-COVID-19 patients.

Identification of soluble biomarkers that associate with distinct manifestations of long COVID

Long coronavirus disease (COVID) is a heterogeneous clinical condition of uncertain etiology triggered by infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Here we used ultrasensitive approaches to profile the immune system and the plasma proteome in healthy convalescent individuals and individuals with long COVID, spanning geographically independent cohorts from Sweden and the United Kingdom. Symptomatic disease was not consistently associated with quantitative differences in immune cell lineage composition or antiviral T cell immunity. Healthy convalescent individuals nonetheless exhibited higher titers of neutralizing antibodies against SARS-CoV-2 than individuals with long COVID, and extensive phenotypic analyses revealed a subtle increase in the expression of some co-inhibitory receptors, most notably PD-1 and TIM-3, among SARS-CoV-2 nonspike-specific CD8+ T cells in individuals with long COVID. We further identified a shared plasma biomarker signature of disease linking breathlessness with apoptotic inflammatory networks centered on various proteins, including CCL3, CD40, IKBKG, IL-18 and IRAK1, and dysregulated pathways associated with cell cycle progression, lung injury and platelet activation, which could potentially inform the diagnosis and treatment of long COVID.

Post-COVID-Syndrome Patients Might Overestimate Own Cognitive Impairment

BACKGROUND

After a COVID-19 infection, some patients experience long-term consequences known as Post-Covid Syndrome, which often includes cognitive impairment. We investigated the congruence between subjectively experienced and objectively measured cognitive deficits after a COVID-19 infection in an unselected, successively admitted cohort of 46 patients reporting subjective cognitive complaints (SCC).

METHODS

We employed a comprehensive neuropsychological test battery to assess objective cognitive impairment across various cognitive domains. Three different cut-off criteria were applied, commonly used in the literature to define objective neurocognitive disorder (NCD).

RESULTS

We observed a notably low congruence between SCC and NCD in Post-Covid Syndrome, regardless of the cut-off criterion. Depending on the cognitive domain, only 4% to maximally 40% of the SCC could be objectified.

CONCLUSIONS

One possible explanation for this discrepancy could be the high rate of depressive symptoms observed in the group of patients studied, which may negatively influence the perception of one's cognitive abilities. These findings emphasize the need for careful evaluation of SCC in Post-Covid Syndrome and suggest that treating depressive symptoms may also alleviate some of the perceived cognitive deficits.

Cardiovascular disease as part of Long COVID: a systematic review

AIMS

Long COVID syndrome has had a major impact on million patients' lives worldwide. The cardiovascular system is an important aspect of this multifaceted disease that may manifest in many ways. We have hereby performed a narrative review in order to identify the extent of the cardiovascular manifestations of the Long COVID syndrome.

METHODS AND RESULTS

An in-depth systematic search of the literature has been conducted for this narrative review. The systematic search of PubMed and Cochrane databases yielded 3993 articles, of which 629 underwent full-text screening. A total of 78 studies were included in the final qualitative synthesis and data evaluation. The pathophysiology of the cardiovascular sequelae of Long COVID syndrome and the cardiac manifestations and complications of Long COVID syndrome are critically evaluated. In addition, potential cardiovascular risk factors are assessed, and preventive methods and treatment options are examined in this review.

CONCLUSION

This systematic review poignantly summarizes the evidence from the available literature regarding the cardiovascular manifestations of Long COVID syndrome and reviews potential mechanistic pathways, diagnostic approaches, preventive measures, and treatment options.

Investigating post-infection anxiety- and depression-like behaviors in a SARS-CoV-2 mouse model

Rationale: The COVID-19 pandemic, driven by SARS-CoV-2, has resulted in a wide range of neuropsychiatric symptoms associated with post-acute sequelae (PASC). However, the mechanisms by which SARS-CoV-2 impacts the brain and leads to persistent behavioral changes remain poorly understood. We hypothesize that SARS-CoV-2 exposure induces neuroinflammation and microglial activation, leading to anxiety- and depression-like behaviors in mice. Methods: We established a SARS-CoV-2 mouse model using the virulent SARS2-N501YMA30 strain to investigate its impact on the central nervous system (CNS). We assessed neuroinvasion via immunostaining of dsRNA and markers for neuronal, astrocyte, and microglia in brain slices. Behavioral changes were evaluated at 2 weeks, 2 months, and 4 months post-infection. Molecular and cellular analyses included bulk RNA-seq, Golgi-Cox staining, field excitatory postsynaptic potential (fEPSP) recordings, immunofluorescence, and quantitative real-time PCR (qRT-PCR) to assess gene expression, neuronal morphology, and microglial activation in the brain. Results: We demonstrated that intranasal inoculation of SARS2-N501YMA30 results in viral dissemination to multiple brain regions, including the amygdala and the prefrontal cortex (PFC). Behavioral assays indicated a marked elevation in anxiety- and depression-like behaviors post-infection. A comparative analysis of RNA expression profiles disclosed alterations in the post-infected brains. Additionally, we observed dendritic spine remodeling on neurons within the amygdala after infection. Infection with SARS2-N501YMA30 was associated with microglial activation and a subsequent increase in microglia-dependent neuronal activity in the amygdala. Transcriptomic analysis of infected brains revealed the upregulation of inflammatory and cytokine-related pathways, implicating neuroinflammation in the pathogenesis of neuronal hyperactivity and behavioral abnormality. Conclusion: Our findings provide evidence that SARS-CoV-2 neuroinvasion plays a critical role in the development of lasting behavioral sequelae observed in PASC. These data provide critical insights into the neurological consequences of SARS-CoV-2 infection and underscore microglia as a potential therapeutic target for ameliorating virus-induced neurobehavioral abnormalities.

Insights into Long COVID: Unraveling Risk Factors, Clinical Features, Radiological Findings, Functional Sequelae and Correlations: A Retrospective Cohort Study

BACKGROUND

The long-term symptomatology of COVID-19 has yet to be comprehensively described. The aim of the study was to describe persistent COVID-19 symptoms in a cohort of hospitalized and home-isolated patients.

METHODS

A retrospective cohort study was conducted on long COVID patients. Long COVID symptoms were identified, and patients were divided into hospitalized (in-patients) and home-isolated (out-patients), as well as according to the number of symptoms. Patients were examined by a multidisciplinary medical team. Blood tests, high resolution chest computed tomography (CT), and physical and infectious examinations were performed. Finally, in-patients were evaluated at 2 time-points: on hospital admission (T0) and 3 months after discharge (Tpost).

RESULTS

There were 364 COVID-19 patients enrolled; 82% of patients reported one or more symptoms. The most reported symptom was fatigue. Chest CT showed alteration in 76% of patients, and pulmonary function alterations were observed in 44.7% of patients. A higher risk of presenting at least one symptom was seen in patients treated with corticosteroid, and a higher risk of presenting chest CT residual lesion was observed in hospitalized patients and in patients that received hydroxychloroquine treatment. Moreover, a higher risk of altered pulmonary function was observed in older patients.

CONCLUSION

Long-term sequelae are present in a remarkable number of long COVID patients and pose a new challenge to the health care system to identify long-lasting effects and improve patients' well-being. Multidisciplinary teams are crucial to develop preventive measures, and clinical management strategies.

Risk, determinants, and persistence of long-COVID in a population-based cohort study in Catalonia

BACKGROUND

Long-COVID has mostly been investigated in clinical settings. We aimed to assess the risk, subtypes, persistence, and determinants of long-COVID in a prospective population-based study of adults with a history of SARS-CoV-2 infection in Catalonia.

METHODS

We examined 2764 infected individuals from a population-based cohort (COVICAT) established before the pandemic and followed up three times across the pandemic (2020, 2021, 2023). We assessed immunoglobulin (Ig)G levels against SARS-CoV-2, clinical, vaccination, sociodemographic, and lifestyle factors. Long-COVID risk and subtypes were defined based on participant-reported symptoms and electronic health records. We identified a total of 647 long-COVID cases and compared them with 2117 infected individuals without the condition.

RESULTS

Between 2021 and 2023, 23% of infected subjects developed long-COVID symptoms. In 56% of long-COVID cases in 2021, symptoms persisted for 2 years. Long-COVID presented clinically in three subtypes, mild neuromuscular, mild respiratory, and severe multi-organ. The latter was associated with persistent long-COVID. Risk was higher among females, participants under 50 years, of low socioeconomic status, severe COVID-19 infection, elevated pre-vaccination IgG levels, obesity, and prior chronic disease, particularly asthma/chronic obstructive pulmonary disease and mental health conditions. A lower risk was associated to pre-infection vaccination, infection after omicron became the dominant variant, higher physical activity levels, and sleeping 6-8 h. Vaccination during the 3 months post-infection was also protective against long-COVID.

CONCLUSIONS

Long-COVID persisted for up to 2 years in half of the cases, and risk was influenced by multiple factors.

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

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.

An Allele of the MTHFR one-carbon metabolism gene predicts severity of COVID-19

While the public health burden of SARS-CoV-2 infection has lessened due to natural and vaccine-acquired immunity, the emergence of less virulent variants, and antiviral medications, COVID-19 continues to take a significant toll. There are > 10,000 new hospitalizations per week in the U.S., many of whom develop post-acute sequelae of SARS-CoV-2 (PASC), or "long COVID", with long-term health issues and compromised quality of life. Early identification of individuals at high risk of severe COVID-19 is key for monitoring and supporting respiratory status and improving outcomes. Therefore, precision tools for early detection of patients at high risk of severe disease can reduce morbidity and mortality. Here we report an untargeted and longitudinal metabolomic study of plasma derived from adult patients with COVID-19. One-carbon metabolism, a pathway previously shown as critical for viral propagation and disease progression, and a potential target for COVID-19 treatment, scored strongly as differentially abundant in patients with severe COVID-19. A follow-up targeted metabolite profiling revealed that one arm of the one-carbon metabolism pathway, the methionine cycle, is a major driver of the metabolic profile associated with disease severity. The methionine cycle produces S-adenosylmethionine (SAM), the methyl group donor important for methylation of DNA, RNA, and proteins, and its high abundance was reported to correlate with disease severity. Further, genomic data from the profiled patients revealed a genetic contributor to methionine metabolism and identified the C677T allele of the MTHFR gene as a pre-existing predictor of disease trajectory - patients homozygous for the MTHFR C677T have higher incidence of experiencing severe disease. Our results raise the possibility that screening for the common genetic MTHFR variant may be an actionable approach to stratify risk of COVID severity and may inform novel precision COVID-19 treatment strategies.

Prevalence of cardiovascular symptoms in post-acute COVID-19 syndrome: a meta-analysis

BACKGROUND

Since its emergence in 2019, COVID-19 has continued to pose significant threats to both the physical and mental health of the global population, as well as to healthcare systems worldwide (Raman et al., Eur Heart J 43:1157-1172, 2022). Emerging evidence indicates that COVID-19 may lead to post-acute COVID-19 syndrome (PACS) with cardiovascular implications, potentially driven by factors such as ACE2 interaction with viruses, systemic inflammation, and endothelial dysfunction. However, there remains a limited amount of research on the cardiovascular manifestations of PACS, which may delay the development of optimal treatment strategies for affected patients. Therefore, it is crucial to investigate the prevalence of cardiovascular sequelae in COVID-19 patients and to determine whether COVID-19 infection acts as an independent risk factor for these outcomes.

METHODS

This meta-analysis adhered to PRISMA guidelines and was registered in PROSPERO (CRD42024524290). A systematic search of PubMed, Embase, and the Cochrane Library was conducted up to March 17, 2024. The primary outcomes included hypertension, palpitations, and chest pain, with pooled effect estimate reported as proportions and odds ratios (ORs) with 95% confidence intervals (CIs). Sensitivity and subgroup analysis were performed to assess the robustness of the results and to identify sources of heterogeneity.

RESULTS

A total of 37 studies, encompassing 2,965,467 patients, were included in the analysis. Pooled results from case-control studies revealed that, compared to the control group, the ORs of chest pain in the COVID-19 group was 4.0 (95% CI: 1.6, 10.0). The ORs for palpitation and hypertension were 3.4 (95% CI: 1.1, 10.2) and 1.7 (95% CI: 1.6, 1.8), respectively. The proportions of PACS patients experiencing chest pain, palpitation, and hypertension as sequelae were 22% (95% CI: 14%, 33%), 18% (95% CI: 13%, 24%), and 19% (95% CI: 12%, 31%), respectively.

CONCLUSIONS

Our findings indicate that 15% of COVID-19 patients experience cardiovascular sequelae. Furthermore, COVID-19 infection significantly increases the likelihood of developing these sequelae compared to uninfected individuals. Future research should prioritize investigating the underlying pathological mechanisms and developing targeted preventive and management strategies.

TRIAL REGISTRATION

CRD42024524290.

Sleep and long COVID: preexisting sleep issues and the risk of post-acute sequelae of SARS-CoV-2 infection in a large general population using 3 different model definitions

STUDY OBJECTIVES

Insomnia, poor sleep quality, and extremes of sleep duration are associated with COVID-19 infection. This study assessed whether these factors are related to post-acute sequelae of SARS-CoV-2 infection (PASC).

METHODS

Cross-sectional survey of a general population of 24,803 United States adults to determine the association of insomnia, poor sleep quality, and sleep duration with PASC. Three definitions of PASC were used based on post COVID-19 clinical features: COVID-19 Outbreak Public Evaluation Initiative (COPE) (≥ 3), National Institute for Health and Care Excellence (NICE) (≥ 1), and Researching COVID to Enhance Recovery (RECOVER) (scoring algorithm).

RESULTS

Prevalence rates of PASC were 21.9%, 38.9%, and 15.5% for COPE, NICE, and RECOVER PASC definitions, respectively. PASC was associated with insomnia in all 3 models after full adjustment with odds ratios and 95% confidence intervals (CIs) ranging from 1.30 (95% CI: 1.11-1.52, P ≤ .05, RECOVER PASC score) to 1.52 (95% CI: 1.34-1.71, P ≤ .001, NICE). Poor sleep quality was related to PASC in all models with adjusted odds ratios ranging from 1.77 (95% CI: 1.60-1.97, P ≤ .001, NICE) to 2.00 (95% CI: 1.77-2.26, P ≤ .001, COPE). Sleep < 6 hours was associated with PASC with adjusted odds ratios between 1.59 (95% CI: 1.40-1.80, P ≤ .001, RECOVER PASC score) and 1.70 (95% CI: 1.53-1.89, P ≤ .001, COPE). Sleep ≥ 9 hours was not associated with PASC in any model. Although vaccination with COVID-19 booster decreased the likelihood of developing PASC, it did not attenuate associations between insomnia, poor sleep quality, and short sleep duration with PASC in any of the models.

CONCLUSIONS

Insomnia, poor sleep quality, and short sleep duration are cross-sectionally associated with PASC and may be potential risk factors. Further longitudinal studies should be conducted.

CITATION

Quan SF, Weaver MD, Czeisler MÉ, et al. Sleep and long COVID: preexisting sleep issues and the risk of post-acute sequelae of SARS-CoV-2 infection in a large general population using 3 different model definitions. J Clin Sleep Med. 2025;21(2):249-259.

Computation and analysis of stationary and periodic solutions of the COVID-19 infection dynamics model

In this work, we search for the conditions for the occurrence of long COVID using the recently developed COVID-19 disease dynamics model which is a system of delay differential equations. To do so, we search for stable stationary or periodic solutions of this model with low viral load that can be interpreted as long COVID using our recently developed technology for analysing time-delay systems. The results of the bifurcation and sensitivity analysis of the mathematical model of SARS-CoV-2 infection suggest the following biological conclusions concerning the mechanisms of pathogenesis of long COVID-19. First, the possibility of SARS-CoV-2 persistence requires a 3-time reduction of the virus production rate per infected cell, or 18-times increase of the antibody-mediated elimination rate of free viruses as compared to an acute infection baseline estimates. Second, the loss of kinetic coordination between virus-induced type I IFN, antibody, and cytotoxic T lymphocyte (CTL) responses can result in the development of mild severity long-lasting infection. Third, the low-level persistent SARS-CoV-2 infection is robust to up to 100-fold perturbations (increase) in viral load and most sensitive to parameters of the humoral immune response.

SARS-COV-2 re-infection and incidence of post-acute sequelae of COVID-19 (PASC) among essential workers in New York: a retrospective cohort study

Background

After surviving Coronavirus Disease 2019 (COVID-19), some people develop symptoms known as post-acute sequelae of COVID-19 (PASC). PASC is an emerging phenomenon yet to be fully understood, and identifying risk factors has been challenging. This study investigated the association between the number of COVID-19 episodes and the incidence of PASC among essential workers.

Methods

We analyzed data from 2511 essential workers, mainly first responders, with confirmed polymerase chain reaction, antibody, or antigen-positive test results for SARS-CoV-2 infection from March 2020 to February 2024. Data were collected through in-person questionnaires and surveys sent via text and email, internal medical records, follow-up calls, and external medical records. Participants who reported continuation or the development of new symptoms three months after the initial SARS-CoV-2 infection, with symptoms lasting for at least two months, were categorized as having PASC, while those without any COVID-19 or whose symptoms resolved were classified as non-PASC. PASC was common in this cohort so we used a Poisson regression model to compute multivariable-adjusted Relative Risk (RR) for the association between risk of PASC and SARS-CoV-2 re-infection, severity, and vaccination status at first infection.

Findings

A total of 475 (prevalence = 18.9%, [95% confidence interval] = [17.4-20.5]) PASC patients were identified. The mean (standard deviation (SD)) age of participants who experienced PASC (54.8 (7.2) years) was similar to those who did not (54.2 (7.4) years). There were 403 (16.1% [14.6-17.5]) participants who experienced multiple instances of COVID-19. After adjusting for relevant demographic, lifestyle, and clinical variables, we found a significant association between the risk of experiencing PASC and multiple SARS-COV-2 infections (RR = 1.41 [1.14-1.74]), severe COVID-19 (RR = 3.17 [2.41-4.16]), and being unvaccinated at first infection (RR = 3.29 [2.46-4.41]).

Interpretation

Although the pathogenetic mechanism for PASC remains unclear, identifying risk factors such as lack of vaccination or re-infection can assist in better understanding and managing the condition.

Funding

National Institute on Aging (NIH/NIA R01 AG049953) and Centers for Disease Control and Prevention (CDC/NIOSH U01 OH011864) and (CDC/NIOSH U01 OH012275).

Long COVID Research, 2020-2024: A PubMed-Based Bibliometric Analysis

Long COVID is a SARS-CoV-2 infection-associated chronic condition with great potential to impact health and socioeconomic outcomes. The research efforts to face the challenges related to long COVID have resulted in a substantial amount of publications, which warrants the need for bibliometric profiling. This is a large-scale PubMed-based bibliometric analysis of more than 390,000 COVID-19 publications. The overall aim was to update the profile of long COVID publications in comparison with the rest of the COVID-19 scientific literature through December 2024. The estimated proportion of long COVID publications was relatively low (2.3% of all COVID-19 publications), although the cumulative frequency (n = 8928) continues to pose a challenge for proper information management. Currently, "treatment" and "mechanism" appear to be the most predominant research topics in the long COVID literature. Interestingly, this evaluation revealed a distinctive profile of the long COVID literature, with a clear preponderance of "case report" and "mechanism" research topics when compared with other COVID-19 publications. This evaluation also identified and ranked the most prolific scientific journals in the production of long COVID-related publications. This study may improve the visibility of long COVID research and contribute to the management of the growing scientific knowledge on long COVID.

Respiratory symptoms after coalmine fire and pandemic: A longitudinal analysis of the Hazelwood Health Study adult cohort

The aim of this study was to determine whether the effects of extreme but discrete PM2.5 exposure from a coal mine fire on respiratory symptoms abated, persisted, or worsened over time, and whether they were exacerbated by COVID-19. We analysed longitudinal survey data from a cohort residing near a 2014 coalmine fire in regional Australia. A 2016/2017 survey included 4,056 participants, of whom 612 were followed-up in 2022. Items included respiratory symptoms, history of COVID-19, and time-location diaries from the mine fire period, which were combined with geospatial and temporal models of fire-related PM2.5. Longitudinal effects of fire-related PM2.5 were examined using a mixed-effects logistic regression model. Exacerbation due to COVID-19 was examined using a logistic regression model. PM2.5 exposure was associated with chronic cough and possibly current wheeze, chest tightness, and current nasal symptoms 2-3 years post-fire, and chronic cough and current wheeze 8.5-9 years post-fire. Further, the association between PM2.5 and chronic cough and possibly current wheeze appeared to increase between the survey periods. While there were no detectable interactions between PM2.5 and COVID-19, PM2.5 exposure was associated with additional respiratory symptoms among participants who reported a history of COVID-19. In summary, medium-duration exposure to extreme levels of fire-related PM2.5 may have increased the long-term risk of chronic cough and current wheeze. While the COVID-19 pandemic started several years after the mine fire, contracting this illness may have exacerbated the effect of fire-related PM2.5 through development of additional respiratory symptoms.

Sparse Bernoulli mixture modeling with negative-unlabeled data: an approach to identify and characterize long COVID

SARS-CoV-2-infected individuals have reported a diverse collection of persistent and often debilitating symptoms commonly referred to as long COVID or post-acute sequelae of SARS-CoV-2 (PASC). Identifying PASC and its subphenotypes is challenging because available data are "negative-unlabeled" as uninfected individuals must be PASC negative, but those with prior infection have unknown PASC status. Moreover, feature selection among many potentially informative characteristics can facilitate reaching a concise and easily interpretable PASC definition. Therefore, to characterize PASC and the spectrum of PASC subphenotypes while identifying a minimal set of features, we propose a Bernoulli mixture model with novel parameterization to accommodate negative-unlabeled data and Bayesian priors to induce sparsity. We present an efficient expectation-maximization algorithm for estimation, and a grid search procedure to select the number of clusters and level of sparsity. We evaluate the proposed method with a simulation study and an analysis of data on self-reported symptoms from the ongoing Researching COVID to Enhance Recovery-Adult Cohort study.

Unveiling risk factors for post-COVID-19 syndrome development in people with type 2 diabetes

Introduction

Post-COVID-19 syndrome (PCS) is a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection-associated chronic condition characterized by long-term violations of physical and mental health. People with type 2 diabetes (T2D) are at high risk for severe COVID-19 and PCS.

Aim

The current study aimed to define the predictors of PCS development in people with T2D for further planning of preventive measures and improving patient outcomes.

Materials and methods

The data were collected through the national survey targeting persons with T2D concerning the history of COVID-19 course and signs and symptoms that developed during or after COVID-19 and continued for more than 12 weeks and were not explained by an alternative diagnosis. In total, 469 patients from different regions of Ukraine were enrolled in the study. Among them, 227 patients reported PCS development (main group), while 242 patients did not claim PCS symptoms (comparison group). Stepwise multivariate logistic regression and probabilistic neural network (PNN) models were used to select independent risk factors.

Results

Based on the survey data, 8 independent factors associated with the risk of PCS development in T2D patients were selected: newly diagnosed T2D (OR 4.86; 95% CI 2.55-9.28; p<0.001), female sex (OR 1.29; 95% CI 0.86-1.94; p=0.220), COVID-19 severity (OR 1.35 95% CI 1.05-1.70; p=0.018), myocardial infarction (OR 2.42 95% CI 1.26-4.64; p=0.002) and stroke (OR 3.68 95% CI 1.70-7.96; p=0.001) in anamnesis, HbA1c above 9.2% (OR 2.17 95% CI 1.37-3.43; p=0.001), and the use of insulin analogs (OR 2.28 95% CI 1.31-3.94; p=0.003) vs human insulin (OR 0.67 95% CI 0.39-1.15; p=0.146). Although obesity aggravated COVID-19 severity, it did not impact PCS development. In ROC analysis, the 8-factor multilayer perceptron (MLP) model exhibited better performance (AUC 0.808; 95% CІ 0.770-0.843), allowing the prediction of the risk of PCS development with a sensitivity of 71.4%, specificity of 76%, PPV of 73.6% and NPV of 73.9%.

Conclusions

Patients who were newly diagnosed with T2D, had HbA1c above 9.2%, had previous cardiovascular or cerebrovascular events, and had severe COVID-19 associated with mechanical lung ventilation were at high risk for PCS.

Acute gastrointestinal and post-acute COVID-19 gastrointestinal syndrome assessment on the Gastrointestinal Symptom Rating Scale scoring system: A questionnaire-based survey

Background

Post-acute coronavirus disease 2019 (COVID-19) syndrome (PACS) is the persistence of sequel of acute SARS-COV-2 infection. Persistent/acquired gastrointestinal symptoms (GI-PACS) include loss of appetite, nausea, weight loss, abdominal pain, heartburn, dysphagia, altered bowel motility, dyspepsia, and irritable bowel syndrome. The study aimed to assess the short- and long-term GI-PACS syndrome on the GSRS scale.

Methods

A cross-sectional, retrospective record analysis and telephonic questionnaire-based survey were conducted at a tertiary referral center in northern India. The data incorporated patients treated from April 2021 to March 2023. Exclusion criteria were neurological disorders, dementia, inability to understand Hindi/English languages, and psychiatric problems. All patients who met the inclusion criteria were telephonically called from November 2023 to January 2024.

Results

The study population was 350 recovered patients from SARS-COVID-19 illness. Forty-three responses were removed during data cleaning and removal of duplication. The data analysis of 307 participants (ICU admissions=92, non-ICU admissions=123, and outdoor treatment =92) was done. The proportion of patients not having any GI symptoms, having at least one GI symptom, and having more than one GI symptom before SARS-COV-2 illness was 3%(3/307), 4.9% (15/307), and 3.6% (11/307), respectively. The four major GI symptoms analyzed in the study were vomiting, pain in the abdomen, diarrhea, and constipation. Overall, 13% (40/307) of the study population did not have any major GI symptoms before SARS-COV-2 diseases. During acute SARS-COV-2 illness, 86.97% (267/307) of patients develop new GI symptoms. Post SARS-COV-2 illness, the overall mean GSRS score for 15 items was 2.14 ± 0.829. The acquired GI-PACS was abdominal pain syndrome (mean score 2.5190 ± SD 0.86650), constipation syndrome (mean score 2.3844 ± 0.83840), reflux syndrome (mean score 2.2866 ± 1.31889), indigestion syndrome (mean score 1.8591 ± 0.93076), and diarrhea syndrome (mean score 1.8122 ± 0.90899). Overall, fever (95.1%, P = 0.007), anosmia (45.0%, P = 0.042), cough (80.1%, P = 0.032), and hospitalization (30.0%, P = 0.003) had a more significant association with one of the major four GI symptoms during the acute phase of SARS-COV-2 illness. Home-isolated patients having loss of appetite (95.4%, P = 0.0001) had a significant association with one of the major four GI symptoms during the acute phase of SARS-COV-2 illness. Hospitalized patients having fever (80.7%, P = 0.031), breathlessness (83.8%, P = 0.003), loss of smell (97.0%, P = 0.001), and cough (82.7%, P = 0.048) had a more significant association with one of the major four GI symptoms during the acute SARS-COV-2 illness. Abdominal pain, reflux, and constipation were considered severe GI symptoms (symptom GSRS score greater than total mean GSRS score). Diarrhea and indigestion were considered mild symptoms (symptom GSRS score was less than the total mean GSRS score). The GI symptoms during acute SARS-COV-2 illness recovered in 66.1% (203/307) patients within 3 months. The respondents taking medicines for more than 1 year following SARS-COV-2 illness were 19.2%. 12.0% (37/307) of respondents suffered from persistent GI symptoms on a mean follow-up of 20.1 ± 0.82 months.

Conclusion

Long-term COVID-19 syndrome frequently manifested as GI symptoms, whereas most symptoms subsided with time.

Post-acute sequelae of SARS-CoV-2 infection (Long COVID) in older adults

Long COVID, also known as PASC (post-acute sequelae of SARS-CoV-2), is a complex infection-associated chronic condition affecting tens of millions of people worldwide. Many aspects of this condition are incompletely understood. Among them is how this condition may manifest itself in older adults and how it might impact the older population. Here, we briefly review the current understanding of PASC in the adult population and examine what is known on its features with aging. Finally, we outline the major gaps and areas for research most germane to older adults.

Clinical features and predictive nomogram for fatigue sequelae in non-severe patients infected with SARS-CoV-2 Omicron variant in Shanghai, China

Background

Patients with coronavirus disease 2019(COVID-2019) infections may still experience long-term effects, with fatigue being one of the most frequent ones. Clinical research on the long COVID in the Chinese population after infection is comparatively lacking.

Objective

To collect and analyze the long-term effects of non-severe COVID-19 infection patients and to develop a model for the prediction of fatigue symptoms.

Methods

223 non-severe COVID-19 patients admitted to one designated hospital were enrolled after finish all the self-designed clinical information registration form and nine-month follow-up. We explored the frequency and symptom types of long COVID. Correlation analysis was done on the neuropsychological scale results. After cluster analysis, lasoo regression and logistic regressions, a nomogram prediction model was produced as a result of investigating the risk factors for fatigue.

Results

A total of 108 (48.4%) of the 223 non-severe COVID-19 patients reported sequelae for more than 4 weeks, and of these, 35 (15.7%) had fatigue sequelae that were scale-confirmed. Other sequelae of more than 10% were brain fog (n = 37,16.6%), cough (n = 26,11.7%) and insomnia (n = 23,10.3%). A correlation between depression and fatigue was discovered following the completion of neuropsychological scale. The duration of hospitalization, the non-use of antiviral medications in treatment, IL-6 and CD16+CD56+ cell levels in blood are the main independent risk factors and predictors of fatigue sequelae in long COVID. Additionally, the neurology diseases and vaccination status may also influence the fatigue sequelae.

Conclusion

Nearly half of the patients infected with COVID-19 Omicron variant complained of sequelae, and fatigue was the most common symptom, which was correlated with depression. Significant predictors of fatigue sequelae included length of hospitalization, non-use of antiviral drug, and immune-related serum markers of IL-6 and CD16+CD56+ NK cell levels. The presence of neurology diseases and a lack of vaccination could also predict the occurrence of fatigue sequelae.

Perceptions of prevalence and management of post-acute sequelae of SARS-CoV-2 (PASC) infection among healthcare workers in Kweneng District, Botswana: Report of a district-wide survey

Over 9.5 million confirmed cases of COVID-19 infection have been recorded in Africa. The syndrome of post-acute sequelae of SARS-CoV-2 infection (PASC) affects an estimated 32% to 87% of COVID patients globally. Data regarding prevalence and impact of PASC in Botswana are limited. This study used a cross-sectional survey design to query healthcare workers in Kweneng District, Botswana about perceived PASC prevalence, duration, symptoms, impact, and management strategies. The survey was disseminated to participants via pre-existing WhatsApp groups and paper copy. Descriptive statistics were used to analyse quantitative data, including demographic data. 72 respondents consented and completed the survey, from an estimated 650 staff meeting eligibility criteria; 63% were female and 36% were male. The majority (90%) were nurses, with doctors and "other" accounting for 6% and 4% of respondents, respectively; no administrators responded. Over half (72%) worked at primary care facilities and 28% worked in hospitals. Nearly all (93%) indicated seeing patients with PASC on a weekly basis, though the majority (61%) identified these patients as comprising <10% of total patients. The most frequently reported PASC symptom was persistent cough (64%), followed by shortness of breath (54%) and fatigue (49%). A substantial minority of respondents were unsure how to manage common PASC symptoms, with 29% and 36% indicating uncertainty regarding management of persistent cough and fatigue, respectively. Findings indicate that PASC symptoms are frequently encountered in clinical practice in Botswana with significant overlap with acute COVID-19, influenza-like illnesses, and tuberculosis, likely placing increased burden on existing health system processes. Providers reported uncertainty in managing presumed PASC, and current practice patterns may contribute to unintended adverse effects. Clear clinical algorithms for PASC screening, diagnosis, and management should be developed and disseminated in Botswana to mitigate the effects of PASC symptoms and improve the quality of life of COVID-19 survivors.

Persistent Symptoms (Lasting Longer than 1 Year) in Children Hospitalized with Acute COVID-19 Versus Other Conditions

Background: We evaluated the prevalence and characteristics of persistent signs and/or symptoms in children and young people (CYP) one year after hospitalization for acute COVID-19 compared with a control group of CYP hospitalized for other conditions. Methods: We conducted an observational study in three hospitals in Madrid, which included a group of children aged between 1 month and 18 years who were hospitalized due to acute COVID-19 from March 2020 to December 2021. We also selected a comparison group of patients hospitalized for other, unrelated conditions within the same month. Eligible participants had no history of COVID-19 at recruitment or during follow-up. Data were collected from clinical records and a standardized questionnaire completed by the patients' families. The primary outcome was the presence of persistent symptoms one year after hospitalization. Results: A total of 96 patients were enrolled and analyzed (50 acute COVID-19 patients and 46 non-COVID-19 participants). Of these, 34/96 (35%) met the criteria for persistent symptoms (CYP: 17/50 (34%) COVID-19 participants and 17/46 (37%) non-COVID-19 participants (p = 0.767)). Symptoms persisted ≥12 months in 14/50 (28%) COVID-19 participants and in 7/46 (15%) non-COVID-19 participants (p = 0.140). Both before and after admission, all of the participants provided similar ratings for all of the specific items related to emotional welfare, social relationships, and current activities. Readmissions occurred in 11/50 (22%) COVID-19 participants and in 6/46 (13%) non-COVID-19 participants (p = 0.267). Conclusions: We identified a non-significant difference in the prevalence of persistent symptoms 1 year after hospitalization between children and young people (CYP) with acute COVID-19 and those hospitalized for non-COVID-19-related conditions.

Cardiac Arrhythmias and Autonomic Dysfunction Associated With COVID-19: A Scientific Statement From the American Heart Association

Cardiac arrhythmias are commonly noted in patients during infections with and recovery from COVID-19. Arrhythmic manifestations span the spectrum of innocuous and benign to life-threatening and deadly. Various pathophysiological mechanisms have been proposed. Debate continues on the impact of incident and exacerbated arrhythmias on the acute and chronic (recovery) phase of the illness. COVID-19 and COVID-19 vaccine-associated myocardial inflammation and autonomic disruption remain concerns. As the pandemic has transformed to an endemic, with discovery of new SARS-CoV-2 variants, updated vaccines, and potent antiviral drugs, vigilance for COVID-19-associated arrhythmic and dysautonomic manifestations remains. The objective of this American Heart Association scientific statement is to review the available evidence on the epidemiology, pathophysiology, clinical presentation, and management of cardiac arrhythmias and autonomic dysfunction in patients infected with and recovering from COVID-19 and to provide evidence-based guidance. The writing committee's consensus on implications for clinical practice, gaps in knowledge, and directions for future research are highlighted.

Red Blood Cell Morphology Is Associated with Altered Hemorheological Properties and Fatigue in Patients with Long COVID

BACKGROUND

SARS-CoV-2 infection adversely affects rheological parameters, particularly red blood cell (RBC) aggregation and deformability, but whether these changes persist in patients suffering from Long-COVID (LC) and whether these changes are related to RBC morphology remain unknown.

METHODS

Venous blood was collected from n = 30 diagnosed LC patients and n = 30 non-LC controls and RBC deformability, RBC aggregation, and hematological parameters were measured. In addition, RBCs were examined microscopically for morphological abnormalities. The mechanical sensitivity index (MS) was assessed in n = 15 LC and n = 15 non-LC samples.

RESULTS

Hematological parameters did not differ between the groups. However, LC showed higher aggregation-related parameters. Although RBC deformability was higher in LC, MS, reflecting the functional capacity to deform, was limited in this group. RBCs from LC showed significantly more morphological abnormalities. The extent of morphological abnormalities correlated with MS and the FACIT-Fatigue score of the LC patients.

CONCLUSION

RBCs from LC show a high degree of morphological abnormalities, which might limit the blood flow determining RBC properties and also be related to fatigue symptomatology in LC. Approaches are now needed to understand the underlying cause of these alterations and to ameliorate these permanent changes.

Prevalence and measurement of post-exertional malaise in post-acute COVID-19 syndrome: A systematic review and meta-analysis

OBJECTIVE

Post-exertional malaise (PEM) is a common and debilitating symptom of post-acute COVID-19 syndrome (PACS), and it is also included in the core outcome set for PACS. Our aims are to determine the prevalence of PEM in patients with PACS, and to review the measurement tools utilized in studies assessing PEM among these patients.

METHODS

A systematic literature search was conducted up to 29 February 2024 across four databases: PubMed, EMBASE, Web of Science, and Cochrane Library. Studies were included if they evaluated PACS individuals who had at least one persistent symptom, with the mean or median follow-up duration of at least 3 months after COVID-19 diagnosis or hospital discharge, and specially reported on PEM or any measurement tools utilized to assess PEM. Data extraction and quality assessment were performed independently by two authors.

RESULTS

After screening 953 articles, 12 studies comprising 2665 patients were included in the meta-analysis, and 16 studies were included in the narrative review. The pooled prevalence of PEM among PACS patients at 3 months or more after COVID-19 diagnosis was 0.55 (95 % CI, 0.38, 0.71). Moreover, narrative review identified seven questionnaires used to assess PEM in PACS individuals, with the DePaul Symptom Questionnaire-Post Exertional Malaise (DSQ-PEM) being the most frequently utilized instrument.

CONCLUSION

Our findings indicate that over half of the PACS individuals experience PEM, and seven questionnaires have been identified for researchers to assess PEM. It is imperative to develop effective intervention strategies to treat and alleviate the burden of PEM.

Inflammatory pathways in patients with post-acute sequelae of COVID-19: The role of the clinical immunologist

As the SARS-CoV-2 pandemic progressed, some survivors noted prolonged symptoms after acute infection, termed post-acute sequelae of COVID-19 (PASC) or "long COVID." PASC is a significant clinical and public health concern that adversely affects patients' quality of life, income, and health care expenses. Moreover, PASC symptoms are highly heterogeneous, the most common being fatigue and cognitive impairment, and they likely reflect a spectrum of clinical phenotypes. The proposed role of persistent inflammation is one of leading pathophysiological theories. This review article addresses these proposed mechanisms of persistent and aberrant inflammation, their clinical evaluation, and theoretical approaches to management. A review of public databases was used to collect literature for the review. The literature supports a prominent role of persistent and aberrant inflammation as a major contributor to the symptoms of PASC. Proposed mechanisms for persistent inflammation include reactivation of latent viruses, viral persistence, loss of immunoregulatory pathways, autoimmune mechanisms, and/or mast cell dysregulation. Persistent inflammation may result in constitutional symptoms such as fatigue, brain fog, body aches, and/or organ-specific dysfunction, such as gastrointestinal dysregulation and myocardial inflammation. There are no approved or even proven therapies for PASC at this time, but some studies have identified therapeutic options that may either reduce the risk for progression to PASC or decrease symptom burden. Laboratory evaluation and therapeutic options are limited and require further investigation to establish their clinical value. A more refined definition of PASC is needed to address the wide variety of clinical presentations, pathophysiology, and therapeutic options.

Neuroinflammation in Post COVID-19 Sequelae: Neuroinvasion and Neuroimmune Crosstalk

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in December 2019 triggered a swift global spread, leading to a devastating pandemic. Alarmingly, approximately one in four individuals diagnosed with coronavirus disease 2019 (COVID-19) experience varying degrees of cognitive impairment, raising concerns about a potential increase in neurological sequelae cases. Neuroinflammation seems to be the key pathophysiological hallmark linking mild respiratory COVID-19 to cognitive impairment, fatigue, and neurological sequelae in COVID-19 patients, highlighting the interaction between the nervous and immune systems following SARS-CoV-2 infection. Several hypotheses have been proposed to explain how the virus disrupts physiological pathways to trigger inflammation within the CNS, potentially leading to neuronal damage. These include neuroinvasion, systemic inflammation, disruption of the lung and gut-brain axes, and reactivation of latent viruses. This review explores the potential origins of neuroinflammation and the underlying neuroimmune cross-talk, highlighting important unanswered questions in the field. Addressing these fundamental issues could enhance our understanding of the virus's impact on the CNS and inform strategies to mitigate its detrimental effects.

The home-based breathing and chest mobility exercise improves cardiorespiratory functional capacity in long COVID with cardiovascular comorbidities: a randomized study

BACKGROUND

Beyond the acute phase, a considerable proportion of patients recovering from the coronavirus disease 2019 (COVID-19) experience long-term sequelae that profoundly impact their quality of life, particularly their physical fitness. This study aims to assess the effect of home-based breathing and chest mobility exercise on the cardiorespiratory functional capacity of long COVID with cardiovascular comorbidity.

METHODS

In this randomized, controlled, single-blind clinical trial, 46 long COVID with cardiovascular comorbidities were randomly assigned to either intervention or control group. The intervention group (n = 23) received additional home-based breathing and chest mobility exercise 3x/week for 12 weeks supervised by attending physicians, whereas the control group only received a home-based cardiac rehabilitation program. Baseline and post-intervention assessments consisted of laboratory (D-Dimer and CRP levels) and functional capacity, assessed through 6-minute walking test (6-MWT), exercise stress test's metabolic equivalents (METS), and predicted peak oxygen consumption (VO2 peak), peak expiratory flow rate (PEFR), peak cough flow (PCF), chest expansion, and EuroQoL's quality of life. Intention to treat analysis was performed.

RESULTS

At the 12th week, intervention subjects had significantly greater functional capacity with higher mean PEFR (p = .031) and PCF (p = .016). Similarly, 6-MWT was higher in the group receiving home-based breathing and chest mobility training (p = .032). The bottom part of the chest circumference was statistically different between the two groups (p = .01). METS and predicted VO2 peak were also higher in the intervention group. However, laboratory parameters and quality of life did not differ markedly (p > .05).

CONCLUSIONS

Home-based respiratory and chest mobility exercise could be an adjunct to cardiac rehabilitation in long COVID with cardiovascular comorbidities for improving cardiorespiratory functional capacity.

TRIAL REGISTRATION

The study protocol was registered at http://ClinicalTrial.gov.id NCT05077943 (14/10/2021).

Mechanisms of long COVID and the path toward therapeutics

Long COVID, a type of post-acute sequelae of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (PASC) defined by medically unexplained symptoms following infection with SARS-CoV-2, is a newly recognized infection-associated chronic condition that causes disability in some people. Substantial progress has been made in defining its epidemiology, biology, and pathophysiology. However, there is no cure for the tens of millions of people believed to be experiencing long COVID, and industry engagement in developing therapeutics has been limited. Here, we review the current state of knowledge regarding the biology and pathophysiology of long COVID, focusing on how the proposed mechanisms explain the physiology of the syndrome and how they provide a rationale for the implementation of a broad experimental medicine and clinical trials agenda. Progress toward preventing and curing long COVID and other infection-associated chronic conditions will require deep and sustained investment by funders and industry.

Chronic lung inflammation and CK14+ basal cell proliferation induce persistent alveolar-bronchiolization in SARS-CoV-2-infected hamsters

BACKGROUND

Post-acute sequalae of COVID-19 defines a wide range of ongoing symptoms and conditions long after SARS-CoV-2 infection including respiratory diseases. The histopathological changes in the lung and underlying mechanism remain elusive.

METHODS

We investigated lung histopathological and transcriptional changes in SARS-CoV-2-infected male hamsters at 7, 14, 42, 84 and 120dpi, and compared with A (H1N1)pdm09 infection.

FINDINGS

We demonstrated viral residue, inflammatory and fibrotic changes in lung after SARS-CoV-2 but not H1N1 infection. The most prominent histopathological lesion was multifocal alveolar-bronchiolization observed in every SARS-CoV-2 infected hamster (31/31), from 42dpi to 120dpi. Proliferating (Ki67+) CK14+ basal cells accumulated in alveoli adjacent to bronchioles at 7dpi, where they proliferated and differentiated into SCGB1A+ club cell or Tubulin+ ciliated cells forming alveolar-bronchiolization foci. Molecularly, Notch pathway significantly upregulated with intensive Notch3 and Hes1 protein expression in alveolar-bronchiolization foci at 42 and 120dpi, suggesting Notch signaling involving the persistence of alveolar-bronchiolization. This is further demonstrated by spatial transcriptomic analysis. Intriguingly, significant upregulation of some cell-growth promoting pathways and genes such as Tubb4b, Stxbp4, Grb14 and Mlf1 were spatially overlapping with bronchiolization lesion.

INTERPRETATION

Incomplete resolution of SARS-CoV-2 infection in lung with viral residue, chronic inflammatory and fibrotic damage and alveolar-bronchiolization impaired respiratory function. Aberrant activation of CK14+ basal cells during tissue regeneration led to persistent alveolar-bronchiolization due to sustained Notch signaling. This study advances our understanding of respiratory PASC, sheds light on disease management and highlights the necessity for monitoring disease progression in people with respiratory PASC.

FUNDING

Funding is listed in the Acknowledgements section.

Personalised Health Behaviour Support Programme in Adults With Post-COVID Syndrome: A Randomised, Controlled Pilot Feasibility Trial

BACKGROUND

We investigated whether a novel 8-week personalised health behaviour support programme, focusing on the stability of symptoms and strategies to improve activities of daily living, was feasible and acceptable in adults with post-COVID syndrome.

METHODS

In this randomised, controlled, pilot feasibility trial, 32 adults with post-COVID syndrome (continued symptoms for ≥ 12 weeks) were randomised 1:1 to receive personalised health behaviour support (self-reported physical activity and symptom diaries, plus seven one-to-one remotely delivered personalised self-management support sessions), once weekly for 8-weeks, or usual care (referral to online 'your COVID-19 recovery' programme). The primary outcome was the feasibility of recruiting and randomising adults with post-COVID syndrome. The secondary outcomes were to assess the acceptability and safety of the intervention and various outcome measures.

RESULTS

Of the 48 adults who expressed interest in the study, 32 (67%) were eligible and completed the baseline assessment. All 32 adults were willing to be randomised to either the personalised health behaviour support programme (n = 17) or usual care (n = 15) and 27 (age: 45 ± 12 years) adults completed follow-up at 9 weeks. The intervention was deemed feasible, with high adherence (92% and 94% completion rates for the physical activity and symptom diaries, respectively) and excellent acceptability rates (94% 'liked the intervention a lot'). The intervention was deemed safe, with no symptom exacerbations reported.

CONCLUSION

An 8-week personalised health behaviour support programme was feasible for adults with post-COVID syndrome, with good adherence and acceptability rates. Early pilot data from this small sample also suggests meaningful improvements in physical activity, fatigue and respiratory symptoms.

PATIENT OR PUBLIC CONTRIBUTION

People living with post-COVID syndrome were involved from the outset with the study design, review of study documentation and interpretation of the data following completion. Furthermore, several participants have supported the local dissemination of findings following the completion of the study.

Sputnik V-Induced Antibodies against SARS-CoV-2 Variants during the Dissemination of the Gamma Variant in Venezuela

The COVID-19 pandemic was characterized by the emergence and succession of SARS-CoV-2 variants able to evade the antibody response induced by natural infection and vaccination. To evaluate the IgG reactivity and neutralizing capacity of the serum of individuals vaccinated with Sputnik V (105 volunteers vaccinated) against different viral variants. IgG reactivity to the Spike protein (S) was evaluated by ELISA. A plaque reduction neutralization test was performed using different viral variant isolates. At 42 days post-vaccination, the frequency of recognition and reactivity to the S protein of the Omicron variant was lower compared to that of the other variants. In general, a higher average neutralization titer was seen against the ancestral variant compared to the variants, especially Omicron. However, some sera exhibited a higher neutralization titer to the Gamma variant compared to the ancestral variant, suggesting unapparent exposure during the clinical trial. Antibodies induced by Sputnik V can recognize, persist, and neutralize SARS-CoV-2 variants, with Omicron being the one that best evades this response. These results represent a unique report on the humoral response induced by a globally lesser-studied vaccine in terms of efficacy and immune escape, offering insights into developing vaccines targeting unknown coronaviruses.

Mechanisms underlying sex differences in autoimmunity

Autoimmune diseases are a leading cause of disability worldwide. Most autoimmune diseases occur more often in women than men, with rheumatic autoimmune diseases being among those most highly expressed in women. Several key factors, identified mainly in animal models and cell culture experiments, are important in increasing autoimmune disease in females. These include sex hormones, immune genes including those found on the X chromosome, sex-specific epigenetic effects on genes by estrogen and the environment, and regulation of genes and messenger RNA by microRNAs found in extracellular vesicles. Evidence is also emerging that viruses as well as drugs or toxins that damage mitochondria may contribute to increased levels of autoantibodies against nuclear and mitochondrial antigens, which are common in many autoimmune diseases. The purpose of this Review is to summarize our current understanding of mechanisms that may determine sex differences in autoimmune disease.

Long-term recovery of taste and smell following acute COVID-19 infection in a New Jersey cohort

Loss of taste and smell is one of the most troubling symptoms of long COVID and may be permanent for some. Correlation between subjectively and objectively assessed olfactory and gustatory impairment is low, leading to uncertainty about how many people are affected, how many recover, and to what extent. We prospectively investigated the effects of COVID-19 on long-term chemosensory function in a university and hospital-based cohort in NJ. We followed 856 participants from March 2020 through April 2022, of which 58 were diagnosed with COVID-19 and completed the NHANES 2013-2014 taste and smell protocol, including a chemosensory questionnaire, whole-mouth taste tests, and an 8-item odor identification test at and/or before acute COVID-19 infection. Of these, 29 repeated taste and smell assessments at 6 months (183.0 ± 54.6) follow-up. Total overall smell score significantly improved from baseline to 6-month follow up (6.9 ± 1.4 vs 7.6 ± 0.8; p = .01). Taste intensity also improved across 6 months, but not significantly. Our study is the first to show psychophysically-assessed and self-reported long-term recovery of olfactory and gustatory function in the same population after acute COVID-19.

Differentiation of Prior SARS-CoV-2 Infection and Postacute Sequelae by Standard Clinical Laboratory Measurements in the RECOVER Cohort

BACKGROUND

There are currently no validated clinical biomarkers of postacute sequelae of SARS-CoV-2 infection (PASC).

OBJECTIVE

To investigate clinical laboratory markers of SARS-CoV-2 and PASC.

DESIGN

Propensity score-weighted linear regression models were fitted to evaluate differences in mean laboratory measures by prior infection and PASC index (≥12 vs. 0). (ClinicalTrials.gov: NCT05172024).

SETTING

83 enrolling sites.

PARTICIPANTS

RECOVER-Adult cohort participants with or without SARS-CoV-2 infection with a study visit and laboratory measures 6 months after the index date (or at enrollment if >6 months after the index date). Participants were excluded if the 6-month visit occurred within 30 days of reinfection.

MEASUREMENTS

Participants completed questionnaires and standard clinical laboratory tests.

RESULTS

Among 10 094 participants, 8746 had prior SARS-CoV-2 infection, 1348 were uninfected, 1880 had a PASC index of 12 or higher, and 3351 had a PASC index of zero. After propensity score adjustment, participants with prior infection had a lower mean platelet count (265.9 × 109 cells/L [95% CI, 264.5 to 267.4 × 109 cells/L]) than participants without known prior infection (275.2 × 109 cells/L [CI, 268.5 to 282.0 × 109 cells/L]), as well as higher mean hemoglobin A1c (HbA1c) level (5.58% [CI, 5.56% to 5.60%] vs. 5.46% [CI, 5.40% to 5.51%]) and urinary albumin-creatinine ratio (81.9 mg/g [CI, 67.5 to 96.2 mg/g] vs. 43.0 mg/g [CI, 25.4 to 60.6 mg/g]), although differences were of modest clinical significance. The difference in HbA1c levels was attenuated after participants with preexisting diabetes were excluded. Among participants with prior infection, no meaningful differences in mean laboratory values were found between those with a PASC index of 12 or higher and those with a PASC index of zero.

LIMITATION

Whether differences in laboratory markers represent consequences of or risk factors for SARS-CoV-2 infection could not be determined.

CONCLUSION

Overall, no evidence was found that any of the 25 routine clinical laboratory values assessed in this study could serve as a clinically useful biomarker of PASC.

PRIMARY FUNDING SOURCE

National Institutes of Health.

Post-Acute Sequelae of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) After Infection During Pregnancy

OBJECTIVE

To estimate the prevalence of post-acute sequelae of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection (PASC) after infection with SARS-CoV-2 during pregnancy and to characterize associated risk factors.

METHODS

In a multicenter cohort study (NIH RECOVER [Researching COVID to Enhance Recovery]-Pregnancy Cohort), individuals who were pregnant during their first SARS-CoV-2 infection were enrolled across the United States from December 2021 to September 2023, either within 30 days of their infection or at differential time points thereafter. The primary outcome was PASC , defined as score of 12 or higher based on symptoms and severity as previously published by the NIH RECOVER-Adult Cohort, at the first study visit at least 6 months after the participant's first SARS-CoV-2 infection. Risk factors for PASC were evaluated, including sociodemographic characteristics, clinical characteristics before SARS-CoV-2 infection (baseline comorbidities, trimester of infection, vaccination status), and acute infection severity (classified by need for oxygen therapy). Multivariable logistic regression models were fitted to estimate associations between these characteristics and presence of PASC.

RESULTS

Of the 1,502 participants, 61.1% had their first SARS-CoV-2 infection on or after December 1, 2021 (ie, during Omicron variant dominance); 51.4% were fully vaccinated before infection; and 182 (12.1%) were enrolled within 30 days of their acute infection. The prevalence of PASC was 9.3% (95% CI, 7.9-10.9%) measured at a median of 10.3 months (interquartile range 6.1-21.5) after first infection. The most common symptoms among individuals with PASC were postexertional malaise (77.7%), fatigue (76.3%), and gastrointestinal symptoms (61.2%). In a multivariable model, the proportion PASC positive with vs without history of obesity (14.9% vs 7.5%, adjusted odds ratio [aOR] 1.65, 95% CI, 1.12-2.43), depression or anxiety disorder (14.4% vs 6.1%, aOR 2.64, 95% CI, 1.79-3.88) before first infection, economic hardship (self-reported difficulty covering expenses) (12.5% vs 6.9%, aOR 1.57, 95% CI, 1.05-2.34), and treatment with oxygen during acute SARS-CoV-2 infection (18.1% vs 8.7%, aOR 1.86, 95% CI, 1.00-3.44) were associated with increased prevalence of PASC.

CONCLUSION

The prevalence of PASC at a median time of 10.3 months after SARS-CoV-2 infection during pregnancy was 9.3% in the NIH RECOVER-Pregnancy Cohort. The predominant symptoms were postexertional malaise, fatigue, and gastrointestinal symptoms. Several socioeconomic and clinical characteristics were associated with PASC after infection during pregnancy.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov , NCT05172024.

Long Neuro-COVID-19: Current Mechanistic Views and Therapeutic Perspectives

Long-lasting COVID-19 (long COVID) diseases constitute a real life-changing burden for many patients around the globe and, overall, can be considered societal and economic issues. They include a variety of symptoms, such as fatigue, loss of smell (anosmia), and neurological-cognitive sequelae, such as memory loss, anxiety, brain fog, acute encephalitis, and stroke, collectively called long neuro-COVID-19 (long neuro-COVID). They also include cardiopulmonary sequelae, such as myocardial infarction, pulmonary damage, fibrosis, gastrointestinal dysregulation, renal failure, and vascular endothelial dysregulation, and the onset of new diabetes, with each symptom usually being treated individually. The main unmet challenge is to understand the mechanisms of the pathophysiologic sequelae, in particular the neurological symptoms. This mini-review presents the main mechanistic hypotheses considered to explain the multiple long neuro-COVID symptoms, namely immune dysregulation and prolonged inflammation, persistent viral reservoirs, vascular and endothelial dysfunction, and the disruption of the neurotransmitter signaling along various paths. We suggest that the nucleoprotein N of SARS-CoV-2 constitutes a "hub" between the virus and the host inflammation, immunity, and neurotransmission.

Long-Term SARS-CoV-2 Findings Related to Persisting Viral Antigen and Inflammation Resemble Those Reported for Influenza Virus and Respiratory Syncytial Virus

Recent studies have documented prolonged expression of viral antigens and RNA and associated inflammation after infection with SARS-CoV-2 in a substantial proportion of infected patients. The persisting SARS-CoV-2 effects and findings, with inflammation associated with continued detection of viral antigens, especially resemble those previously reported for influenza virus, as well as respiratory syncytial virus (RSV). The reports indicate the need for improved insight into the mechanisms whereby post-SARS-CoV-2 infection-related illness is apparently more common and perhaps even more persistent after infection than observed for other respiratory viruses.

Characterizing Long COVID in Children and Adolescents

Importance

Most research to understand postacute sequelae of SARS-CoV-2 infection (PASC), or long COVID, has focused on adults, with less known about this complex condition in children. Research is needed to characterize pediatric PASC to enable studies of underlying mechanisms that will guide future treatment.

Objective

To identify the most common prolonged symptoms experienced by children (aged 6 to 17 years) after SARS-CoV-2 infection, how these symptoms differ by age (school-age [6-11 years] vs adolescents [12-17 years]), how they cluster into distinct phenotypes, and what symptoms in combination could be used as an empirically derived index to assist researchers to study the likely presence of PASC.

Design, Setting, and Participants

Multicenter longitudinal observational cohort study with participants recruited from more than 60 US health care and community settings between March 2022 and December 2023, including school-age children and adolescents with and without SARS-CoV-2 infection history.

Exposure

SARS-CoV-2 infection.

Main Outcomes and Measures

PASC and 89 prolonged symptoms across 9 symptom domains.

Results

A total of 898 school-age children (751 with previous SARS-CoV-2 infection [referred to as infected] and 147 without [referred to as uninfected]; mean age, 8.6 years; 49% female; 11% were Black or African American, 34% were Hispanic, Latino, or Spanish, and 60% were White) and 4469 adolescents (3109 infected and 1360 uninfected; mean age, 14.8 years; 48% female; 13% were Black or African American, 21% were Hispanic, Latino, or Spanish, and 73% were White) were included. Median time between first infection and symptom survey was 506 days for school-age children and 556 days for adolescents. In models adjusted for sex and race and ethnicity, 14 symptoms in both school-age children and adolescents were more common in those with SARS-CoV-2 infection history compared with those without infection history, with 4 additional symptoms in school-age children only and 3 in adolescents only. These symptoms affected almost every organ system. Combinations of symptoms most associated with infection history were identified to form a PASC research index for each age group; these indices correlated with poorer overall health and quality of life. The index emphasizes neurocognitive, pain, and gastrointestinal symptoms in school-age children but change or loss in smell or taste, pain, and fatigue/malaise-related symptoms in adolescents. Clustering analyses identified 4 PASC symptom phenotypes in school-age children and 3 in adolescents.

Conclusions and Relevance

This study developed research indices for characterizing PASC in children and adolescents. Symptom patterns were similar but distinguishable between the 2 groups, highlighting the importance of characterizing PASC separately for these age ranges.

Long COVID: a clinical update

Post-COVID-19 condition (also known as long COVID) is generally defined as symptoms persisting for 3 months or more after acute COVID-19. Long COVID can affect multiple organ systems and lead to severe and protracted impairment of function as a result of organ damage. The burden of this disease, both on the individual and on health systems and national economies, is high. In this interdisciplinary Review, with a coauthor with lived experience of severe long COVID, we sought to bring together multiple streams of literature on the epidemiology, pathophysiology (including the hypothesised mechanisms of organ damage), lived experience and clinical manifestations, and clinical investigation and management of long COVID. Although current approaches to long COVID care are largely symptomatic and supportive, recent advances in clinical phenotyping, deep molecular profiling, and biomarker identification might herald a more mechanism-informed and personally tailored approach to clinical care. We also cover the organisation of services for long COVID, approaches to preventing long COVID, and suggestions for future research.

Study of Postacute Sequelae of COVID-19 Using Digital Wearables: Protocol for a Prospective Longitudinal Observational Study

BACKGROUND

Postacute sequelae of COVID-19 (PASC) remain understudied in nonhospitalized patients. Digital wearables allow for a continuous collection of physiological parameters such as respiratory rate and oxygen saturation that have been predictive of disease trajectories in hospitalized patients.

OBJECTIVE

This protocol outlines the design and procedures of a prospective, longitudinal, observational study of PASC that aims to identify wearables-collected physiological parameters that are associated with PASC in patients with a positive diagnosis.

METHODS

This is a single-arm, prospective, observational study of a cohort of 550 patients, aged 18 to 65 years, male or female, who own a smartphone or a tablet that meets predetermined Bluetooth version and operating system requirements, speak English, and provide documentation of a positive COVID-19 test issued by a health care professional within 5 days before enrollment. The primary end point is long COVID-19, defined as ≥1 symptom at 3 weeks beyond the first symptom onset or positive diagnosis, whichever comes first. The secondary end point is chronic COVID-19, defined as ≥1 symptom at 12 weeks beyond the first symptom onset or positive diagnosis. Participants must be willing and able to consent to participate in the study and adhere to study procedures for 6 months.

RESULTS

The first patient was enrolled in October 2021. The estimated year for publishing the study results is 2025.

CONCLUSIONS

This is a fully decentralized study investigating PASC using wearable devices to collect physiological parameters and patient-reported outcomes. The study will shed light on the duration and symptom manifestation of PASC in nonhospitalized patient subgroups and is an exemplar of the use of wearables as population-level monitoring health tools for communicable diseases.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04927442; https://clinicaltrials.gov/study/NCT04927442.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/57382.