Long COVID-19 Pathophysiology: What Do We Know So Far?

Cardiac symptoms in patients 3-6 months after contracting COVID-19- data from the polish STOP-COVID registry

BACKGROUND

Common complaints of long COVID patients are cardiac symptoms such as fatigue, weakness, and a feeling of palpitations. The study aimed to investigate the clinical features of patients with persistent cardiological symptoms occurring within 3 to 6 months after COVID-19. Differences in ambulatory blood pressure monitoring (ABPM), Holter ECG (electrocardiogram) and Echocardiography between people with and without persistent cardiological symptoms were evaluated. We also assessed whether the symptoms of anxiety and depression may be implicated in the clinical outcomes.

MATERIALS AND METHODS

This was a retrospective study of patients affiliated with the STOP-COVID registry who attended a follow-up visit 3-6 months after undergoing COVID-19. The visit assessed the clinical symptoms present and performed tests: ABPM, Holter ECG and Echocardiography. 504 patients additionally had GAD-2 (Generalized Anxiety Disorder 2-item) and PHQ-2 (Patient Health Questionnaire-2) tests performed.

RESULTS

The analysis included 1080 patients. At least 1 of the analyzed symptoms was present in 586 patients (54.3%). The most common symptom was fatigue (38.9%). Comparing patients with or without palpitations showed that the mean value of ventricular extrasystole was higher in the former group (p = 0.011). Comparing patients with and without cardiac symptoms, there were differences in the mean values of the PHQ-2 (p = 0.022) and GAD-2 (p < 0.001) scales, as well as in the percentage of responses related to the risk of anxiety or depression.

CONCLUSION

Cardiological symptoms are common among health issues that patients must face after contracting COVID-19. People with palpitations had more excessive ventricular extrasystoles than patients without these symptoms.

TRIAL REGISTRATION

Our retrospective study was based on analysis of medical data of patients with COVID-19 treated on out-patient basis in the STOP-COVID registry of the Polish Long-Covid Cardiovascular (PoLoCOV-CVD) study (ClinicalTrials.gov identifier- NCT05018052, the registration date 29.05.2020). Consent to conduct the study was obtained from the Bioethics Committee of the District Medical Chamber in Lodz (no. KB-0115/2021).

Impact of Pulmonary Comorbidities on COVID-19: Acute and Long-Term Evaluations

Background/Objectives: Pulmonary comorbidities, such as chronic obstructive pulmonary disease (COPD), asthma, and interstitial lung diseases (ILDs), have emerged as critical factors influencing the severity and outcomes of COVID-19. This review aims to evaluate the interplay between these comorbidities and COVID-19, both during the acute phase and in long-term recovery, focusing on their impact on clinical management and outcomes. Methods: This systematic review examined studies sourced from major medical databases, including PubMed and Scopus, using keywords such as "COVID-19", "pulmonary comorbidities", "long COVID", and "respiratory sequelae". Peer-reviewed articles published from January 2020 to the present were included, with data extracted to evaluate both the acute and long-term effects of these comorbidities on COVID-19 patients. Results: Patients with COPD demonstrated significantly higher risks of severe COVID-19, including increased hospitalization and mortality. Asthma, while less consistently associated with severe outcomes, showed a variable risk based on disease control. ILDs were strongly correlated with poor outcomes, including higher rates of respiratory failure and mortality. Long-term complications, such as persistent dyspnea, impaired lung function, and structural changes like fibrosis, were prevalent in patients recovering from moderate to severe COVID-19. These complications adversely affected quality of life and increased healthcare dependency. Conclusions: Pulmonary comorbidities amplify both the acute severity and long-term respiratory consequences of COVID-19. Effective management necessitates tailored strategies addressing both phases, integrating rehabilitation and continuous monitoring to mitigate chronic impairments. Future research should prioritize understanding the mechanisms behind these interactions to inform public health interventions and improve patient outcomes.

Effects of Long COVID in Patients with Severe Coronavirus Disease 2019 on Long-Term Functional Impairments: A Post Hoc Analysis Focusing on Patients Admitted to the ICU in the COVID-19 Recovery Study II

Background/Objectives: This study investigated the prevalence of functional impairments and the effects of long COVID on long-term functional impairments in patients with severe COVID-19. Methods: We conducted a nationwide multicenter cohort study in collaboration with nine hospitals, collecting data using self-administered questionnaires from participants aged 20 years or older who were diagnosed with COVID-19, admitted to the intensive care unit (ICU) between April 2021 and September 2021, and discharged alive. Questionnaires regarding daily life, sequela, and functional impairments were mailed to patients in August 2022. The effects of long COVID on functional impairments were examined using a multivariate logistic regression analysis. Results: The survey was completed by 220 patients, with a mean of 416 days after discharge. Among respondents, 20.5% had physical impairments (n = 45), 35.0% had mental disorders (n = 77), and 42.7% had either (n = 94). Furthermore, 77.7% had long COVID (171/220), and the most common symptom was dyspnea (40.0%). The multivariate analysis showed that fatigue/malaise, upper respiratory tract symptoms, myalgia, muscle weakness, decreased concentration, sleep disorder, brain fog, and dizziness were risk factors for functional impairments at one year. Conclusions: Many patients with severe COVID-19 admitted to the ICU still suffered from post-intensive care syndrome even after one year, which manifested in combination with direct symptoms of the original disease, such as long COVID.

SARS-CoV-2 vaccination influence in the development of long-COVID clinical phenotypes

Although SARS-CoV-2 vaccination reduces hospitalization and mortality, its long-term impact on Long-COVID remains to be elucidated. The aim of the study was to evaluate the different development of Long-COVID clinical phenotypes according to the vaccination status of patients. Clinical and demographic characteristics were assessed for each patient, while Long-COVID symptoms were self-reported and later stratified into distinct clinical phenotypes. Vaccination was significantly associated with the avoidance of hospitalization, less invasive respiratory support, and less alterations of cardiopulmonary functions, as well as reduced lasting lung parenchymal damage. However, no association between vaccination status and the development of at least one Long-COVID symptom was found. Nevertheless, clinical phenotypes were differently associated with vaccination status, as neuropsychiatric were more frequent in unvaccinated patients and cardiorespiratory symptoms were reported mostly in vaccinated patients. Different progression of disease could be at play in the different development of specific Long-COVID clinical phenotypes, as shown by the different serological responses between unvaccinated and vaccinated patients. A higher anti-Spike (S) antibody titre was protective for vaccinated patients, while it was detrimental for unvaccinated patients. A better understanding of the mechanism underlying the development of Long-COVID symptoms might be reached by standardized methodologies and symptom classification.

The Role of Memory T-Cell Mediated Immunity in Long-term COVID-19: Effects of Vaccination Status

T-cell-mediated immunity is essential for controlling severe acute respiratory syndrome coronavirus 2 (SARSCoV2) infection, preventing severe disease, and potentially reducing the risk of long-term coronavirus disease (COVID). This study investigated the impact of natural infection, vaccination, and hybrid immunity on T-cell responses, with a particular emphasis on the role of memory T-cells in long-term COVID-19. The present study reviewed current literature on T-cell responses, including memory T-cell development, in individuals with natural SARS-CoV-2 infection, those vaccinated with messenger RNA (mRNA) vaccines, and those with hybrid immunity. It examined studies that compared T-cell activity, immune regulation, and the prevalence of long-term COVID-19 across these groups. Natural infection induces variable T-cell responses, with severe cases showing stronger but sometimes dysregulated immunological activity, which may contribute to prolonged COVID-19. Vaccination, particularly with mRNA vaccines, elicits targeted and consistent T-cell responses, including memory T-cells, reducing disease severity, and the incidence of long-term COVID-19. Hybrid immunity combines natural infection and vaccination, provides the most robust protection, enhanceds memory T-cell responses, and reduces the risk of long-term COVID-19 through balanced immune regulation. Memory T-cells play a critical role in mitigating long-term COVID-19. Vaccination significantly enhances T-cell-mediated immunity, minimizing the risk of chronic symptoms compared to natural infection alone. Hybrid immunity provides the most effective defense, emphasizing the importance of vaccination, even after natural infection, to prevent long-term COVID-19.

The Relationship Between Long Covid Symptoms and Vaccination Status in COVID-19 Survivors

BACKGROUND

The positive effects of vaccination status on the course of Long COVID symptoms have not been fully elucidated. Our aim is to determine the most common Long COVID symptoms in patients monitored in the COVID-19 follow-up clinic and to examine whether there is a difference between the recovery rates of those who are vaccinated and those who are not vaccinated.

METHOD

Between December 1, 2020 and April 30, 2022, prospectively collected data of 916 patients who were admitted to the COVID-19 follow-up outpatient clinic of a tertiary hospital for the first time were evaluated as a retrospective cohort in this study. The frequencies of the ten most common symptoms in the first and last examinations of 478 patients with Long COVID symptoms were determined, and their recovery was compared. Patients were divided into two groups according to their vaccination status. The values showing the recovery rates obtained for these two groups were compared between themselves again.

RESULTS

The average age of the patients in the study group was 54.43 ± 11.71 years, and 255 (53.3%) were male. The median follow-up period was 10 months. 84.7% of patients had received at least one dose of vaccine. Statistically significant results were found for improvement in all ten symptoms in vaccinated patients compared to the never-vaccinated group. There was no statistically significant difference between the CoronaVac, BNT162b2, and heterologous (CoronaVac+ BNT162b2) vaccine groups. Factors affecting recovery for the three most common symptoms (dyspnea, fatigue, forgetfulness) were examined with univariate logistic regression analysis, and only vaccination or non-vaccination was found to be a significant risk factor.

CONCLUSION

This study showed that receiving vaccination may be effective in improving Long COVID symptoms. Although there were no statistically significant differences between the inactive vaccine CoronaVac, the mRNA vaccine BNT162b2, and the heterologous (CoronaVac+ BNT162b2) vaccine in terms of reducing Long COVID symptoms, higher recovery rates were detected in those who received the mRNA vaccine BNT162b2.

General practice registrar evaluation of long COVID in patients presenting with fatigue

Background Long COVID is a new and prevalent condition defined by persistent symptoms following acute COVID-19 infection. While increasing resources are being directed to management, there is little evidence on how general practitioners (GPs) have changed their assessment and differential diagnosis of patients with potential long COVID symptoms including fatigue. This study aimed to examine how often GP registrars consider long COVID in patients presenting with fatigue, how often they think long COVID might be the cause for fatigue, and patient, registrar, practice, and consultation factors associated with these outcomes. Methods Data were collected through Registrar Clinical Encounters in Training (ReCEnT), an ongoing inception cohort study of GP registrars' in-consultation experiences, during two collection rounds in 2022-2023. Multivariable logistic regression was used to examine the relationship between predictor variables and outcomes. Results A total of 969 registrars recorded 3193 consultations where fatigue was a symptom. Registrars reported considering long COVID as a differential diagnosis in 2563 encounters (80%, 95% confidence interval (CI) 79-82%). Of these, registrars thought long COVID was the likely cause for fatigue in 465 encounters (18%, 95% CI 17-20%). While no patient variables were significantly associated with either outcome, multivariable associations included telehealth consultations having greater odds of both outcomes and Australian-trained registrars having lesser odds of considering long COVID likely. Conclusions Registrars report usually considering long COVID as a differential for fatigue and frequently considering it a likely diagnosis. Telehealth usage was significantly associated with both outcomes. Future work should explore GPs' diagnostic approaches to other potential long COVID symptoms.

Cardiovascular Symposium on Perspectives in Long COVID

Significant progress has been made in treating Coronavirus disease (COVID) - an infectious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). An ominous turn in the pandemic is the evolving public health crisis emanating from persistent SARS-CoV-2 infection and its associated long-term impact. Long COVID or post-COVID syndrome describes protean symptoms that persist at least 3 months after the onset of acute illness and last for at least 2 months in individuals with a history of confirmed SARS-CoV-2 infection. Long COVID has become a public health concern. Millions of infected individuals are now facing chronic multi-organ failures, including neuropsychiatric, cardiovascular, pulmonary, and kidney complications. In general, the cause of long COVID syndrome is unclear but factors such as prolonged activation of immune responses, and viral persistence triggering transcription dysregulation of genes associated with normal thrombotic disease may play a role in cardiovascular complications. Although inflammatory biomarkers are reported in other disorders, it remains unclear whether similar biomarkers are associated with cardiovascular manifestations following COVID. Medications such as sulodexide directed at glycocalyx and coagulation have demonstrated benefits for long COVID in smaller studies. Here, we describe the outcomes of the symposium on the underlying cardiovascular mechanisms of the long COVID.

Neurological, psychological, psychosocial complications of long-COVID and their management

Since it first appeared, Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has had a significant and lasting negative impact on the health and economies of millions of individuals all over the globe. At the level of individual health too, many patients are not recovering fully and experiencing a long-term condition now commonly termed 'long-COVID'. Long-COVID is a collection of symptoms which must last more than 12 weeks following initial COVID infection, and which cannot be adequately explained by alternate diagnoses. The neurological and psychosocial impact of long-COVID is itself now a global health crisis and therefore preventing, diagnosing, and managing these patients is of paramount importance. This review focuses primarily on: neurological functioning deficits; mental health impacts; long-term mood problems; and associated psychosocial issues, among patients suffering from long-COVID with an eye towards the neurological basis of these symptoms. A concise account of the clinical relevance of the neurological and psychosocial impacts of long-COVID, the effects on long-term morbidity, and varied approaches in managing patients with significant chronic neurological symptoms and conditions was extracted from the literature, analysed and reported. A comprehensive account of plausible pathophysiological mechanisms involved in the development of long-COVID, its management, and future research needs have been discussed.

Is there a rationale for hyperbaric oxygen therapy in the patients with Post COVID syndrome? : A critical review

The SARS-CoV-2 pandemic has resulted in 762 million infections worldwide from 2020 to date, of which approximately ten percent are suffering from the effects after infection in 2019 (COVID-19) [1, 40]. In Germany, it is now assumed that at least one million people suffer from post-COVID condition with long-term consequences. These have been previously reported in diseases like Myalgic Encephalomyelitis (ME) and Chronic Fatigue Syndrome (CFS). Symptoms show a changing variability and recent surveys in the COVID context indicate that 10-30 % of outpatients, 50 to 70% of hospitalised patients suffer from sequelae. Recent data suggest that only 13% of all ill people were completely free of symptoms after recovery [3, 9]. Current hypotheses consider chronic inflammation, mitochondrial dysfunction, latent viral persistence, autoimmunity, changes of the human microbiome or multilocular sequelae in various organ system after infection. Hyperbaric oxygen therapy (HBOT) is applied since 1957 for heart surgery, scuba dive accidents, CO intoxication, air embolisms and infections with anaerobic pathogens. Under hyperbaric pressure, oxygen is physically dissolved in the blood in higher concentrations and reaches levels four times higher than under normobaric oxygen application. Moreover, the alternation of hyperoxia and normoxia induces a variety of processes at the cellular level, which improves oxygen supply in areas of locoregional hypoxia. Numerous target gene effects on new vessel formation, anti-inflammatory and anti-oedematous effects have been demonstrated [74]. The provision of intermittently high, local oxygen concentrations increases repair and regeneration processes and normalises the predominance of hyperinflammation. At present time only one prospective, randomized and placebo-controlled study exists with positive effects on global cognitive function, attention and executive function, psychiatric symptoms and pain interference. In conclusion, up to this date HBO is the only scientifically proven treatment in a prospective randomized controlled trial to be effective for cognitive improvement, regeneration of brain network and improvement of cardiac function. HBOT may have not only theoretical but also potential impact on targets of current pathophysiology of Post COVID condition, which warrants further scientific studies in patients.

Lights and Shadows of Long COVID: Are Latent Infections the Real Hidden Enemy?

Long COVID-19 (LC) is a poorly understood, multifactorial condition that persists for at least three months following SARS-CoV-2 infection. The underlying pathophysiological mechanisms responsible for the wide range of associated symptoms-including fatigue, brain fog, and respiratory issues-remain unclear. However, emerging evidence suggests that the reactivation of latent viral infections, such as Epstein-Barr virus, cytomegalovirus, and varicella-zoster virus, may significantly contribute to the complexity of LC. These latent viruses can be reactivated by SARS-CoV-2, contributing to a chronic inflammatory state that prolongs symptomatology. This review confirms the potential involvement of latent viral infections in LC and examines whether these infections play an independent role or act synergistically with other factors. In addition, recent studies have highlighted viral persistence and immune dysregulation as key elements in LC. Our findings suggest that preventative strategies, including vaccination and antiviral treatments during the acute phase of COVID-19, show potential in reducing LC risk by preventing viral reactivation. However, tailored diagnostic and therapeutic strategies targeting these latent infections are urgently needed. Identifying biomarkers of viral reactivation, particularly for high-risk populations, could be considered another effective strategy to mitigate LC severity. Further research is crucial to better understand the interactions between SARS-CoV-2 and latent infections, and to improve the prevention and treatment of LC.

Neurovascular unit, neuroinflammation and neurodegeneration markers in brain disorders

Neurovascular unit (NVU) inflammation via activation of glial cells and neuronal damage plays a critical role in neurodegenerative diseases. Though the exact mechanism of disease pathogenesis is not understood, certain biomarkers provide valuable insight into the disease pathogenesis, severity, progression and therapeutic efficacy. These markers can be used to assess pathophysiological status of brain cells including neurons, astrocytes, microglia, oligodendrocytes, specialized microvascular endothelial cells, pericytes, NVU, and blood-brain barrier (BBB) disruption. Damage or derangements in tight junction (TJ), adherens junction (AdJ), and gap junction (GJ) components of the BBB lead to increased permeability and neuroinflammation in various brain disorders including neurodegenerative disorders. Thus, neuroinflammatory markers can be evaluated in blood, cerebrospinal fluid (CSF), or brain tissues to determine neurological disease severity, progression, and therapeutic responsiveness. Chronic inflammation is common in age-related neurodegenerative disorders including Alzheimer's disease (AD), Parkinson's disease (PD), and dementia. Neurotrauma/traumatic brain injury (TBI) also leads to acute and chronic neuroinflammatory responses. The expression of some markers may also be altered many years or even decades before the onset of neurodegenerative disorders. In this review, we discuss markers of neuroinflammation, and neurodegeneration associated with acute and chronic brain disorders, especially those associated with neurovascular pathologies. These biomarkers can be evaluated in CSF, or brain tissues. Neurofilament light (NfL), ubiquitin C-terminal hydrolase-L1 (UCHL1), glial fibrillary acidic protein (GFAP), Ionized calcium-binding adaptor molecule 1 (Iba-1), transmembrane protein 119 (TMEM119), aquaporin, endothelin-1, and platelet-derived growth factor receptor beta (PDGFRβ) are some important neuroinflammatory markers. Recent BBB-on-a-chip modeling offers promising potential for providing an in-depth understanding of brain disorders and neurotherapeutics. Integration of these markers in clinical practice could potentially enhance early diagnosis, monitor disease progression, and improve therapeutic outcomes.

Insights into COVID-19 pathophysiology from a longitudinal multisystem report during acute infection

The Coronavirus disease 2019 (COVID-19), an illness caused by a SARS-CoV-2 viral infection, has been associated with neurological and neuropsychiatric disorders, revealing its impact beyond the respiratory system. Most related research involved individuals with post-acute or persistent symptoms of COVID-19, also referred to as long COVID or Post-Acute Sequelae of COVID-19 (PASC). In this longitudinal unique report, we aimed to describe the acute supraspinal and corticospinal changes and functional alterations induced by a COVID-19 infection using neuroimaging, neurophysiological and clinical assessment of a participant during acute infection, as compared to three other visits where the participant had no COVID-19. The results favor a multisystem impairment, impacting cortical activity, functional connectivity, and corticospinal excitability, as well as motor and cardiovascular function. The report suggests pathophysiological alteration and impairment already present at the acute stage, that if resolved tend to lead to a full clinical recovery. Such results could be also insightful into PASC symptomatology.

Successful treatment with guanfacine in a long-COVID case manifesting marked cognitive impairment

BACKGROUND

Persistent cognitive impairment is a serious consequence of the post-COVID condition. However, there have been no established effective treatments for this pathophysiology supported by sufficient evidence.

CASE PRESENTATION

A 32-year-old woman became aware of difficulty in word recalling, reading, and writing as well as difficulty in completing various household multitasks 3 weeks after the COVID-19 infection. Although blood tests, magnetic resonance imaging, electroencephalography, and Kohs block design test were all within normal limits, completion time by trail making test (TMT) A or B was markedly delayed. Finally, she was referred to our hospital 3 months after the infection. At baseline, the THINC integrated tool (THINC-it), a digital battery consisting of the five-item version of the perceived deficit questionnaire (PDQ-5), choice reaction time (CRT), 1-back test, digit symbol substitution test (DSST), and TMT-B, revealed poor capability in attention, working memory, and executive function. Also, near-infrared spectroscopy (NIRS) demonstrated no activation in frontal or temporal regions during verbal fluency task. Extended-release guanfacine (GXR) 2 mg/day was initiated and a month later was elevated up to 4 mg/day as a maintenance dose. The PDQ-5, CRT, 1-back test, DSST, and TMT-B were dramatically improved 1 month after GXR treatment. NIRS finding was also normalized after 2 months of treatment. These effects were successfully maintained throughout the 6-month follow-up period.

CONCLUSION

GXR may be helpful in improving subjective/objective cognitive functioning and frontotemporal brain activity in long-COVID patients manifesting apparent cognitive impairment.

A Blood Supply Pathophysiological Microcirculatory Mechanism for Long COVID

BACKGROUND

The term "Long COVID" is commonly used to describe persisting symptoms after acute COVID-19. Until now, proposed mechanisms for the explanation of Long COVID have not related quantitative measurements to basic laws. In this work, a common framework for the Long COVID pathophysiological mechanism is presented, based on the blood supply deprivation and the flow diffusion equation.

METHODS

Case-control studies with statistically significant differences between cases (post-COVID patients) and controls, from multiple tissues and geographical areas, were gathered and tabulated. Microvascular loss (ML) was quantified by vessel density reduction (VDR), foveal avascular zone enlargement (FAZE), capillary density reduction (CDR), and percentage of perfused vessel reduction (PPVR). Both ML and hemodynamic decrease (HD) were incorporated in the tissue blood supply reduction (SR) estimation.

RESULTS

ML data were found from 763 post-COVID patients with an average VDR, FAZE, CDR, and PPVR of 16%, 31%, 14%, and 21%, respectively. The average HD from 72 post-COVID patients was 37%. The estimated SR for multiple tissues with data from 634 post-COVID patients reached a sizeable 47%. This large SR creates conditions of lower mass diffusion rates, hypoxia, and undernutrition, which at a multi-tissue level, for a long time, can explain the wide variety of the Long COVID symptoms.

CONCLUSIONS

Disruption of peripheral tissue blood supply by the contribution of both ML and HD is proposed here to be the principal cause of the mechanism leading to Long COVID symptoms.

Post-Acute Sequelae and Mitochondrial Aberration in SARS-CoV-2 Infection

This review investigates links between post-acute sequelae of SARS-CoV-2 infection (PASC), post-infection viral persistence, mitochondrial involvement and aberrant innate immune response and cellular metabolism during SARS-CoV-2 infection. Advancement of proteomic and metabolomic studies now allows deeper investigation of alterations to cellular metabolism, autophagic processes and mitochondrial dysfunction caused by SARS-CoV-2 infection, while computational biology and machine learning have advanced methodologies of predicting virus-host gene and protein interactions. Particular focus is given to the interaction between viral genes and proteins with mitochondrial function and that of the innate immune system. Finally, the authors hypothesise that viral persistence may be a function of mitochondrial involvement in the sequestration of viral genetic material. While further work is necessary to understand the mechanisms definitively, a number of studies now point to the resolution of questions regarding the pathogenesis of PASC.

The Association of Genetic Markers Involved in Muscle Performance Responding to Lactate Levels during Physical Exercise Therapy by Nordic Walking in Patients with Long COVID Syndrome: A Nonrandomized Controlled Pilot Study

Several genetic markers have shown associations with muscle performance and physical abilities, but the response to exercise therapy is still unknown. The aim of this study was to test the response of patients with long COVID through an aerobic physical therapy strategy by the Nordic walking program and how several genetic polymorphisms involved in muscle performance influence physical capabilities. Using a nonrandomized controlled pilot study, 29 patients who previously suffered from COVID-19 (long COVID = 13, COVID-19 = 16) performed a Nordic walking exercise therapy program for 12 sessions. The influence of the ACE (rs4646994), ACTN3 (rs1815739), AMPD1 (rs17602729), CKM (rs8111989), and MLCK (rs2849757 and rs2700352) polymorphisms, genotyped by using single nucleotide primer extension (SNPE) in lactic acid concentration was established with a three-way ANOVA (group × genotype × sessions). For ACE polymorphism, the main effect was lactic acid (p = 0.019). In ACTN3 polymorphism, there were no main effects of lactic acid, group, or genotype. However, the posthoc analysis revealed that, in comparison with nonlong COVID, long COVID increased lactic acid concentrations in Nordic walking sessions in CT and TT genotypes (all p < 0.05). For AMPD1 polymorphism, there were main effects of lactic acid, group, or genotype and lactic acid × genotype or lactic acid × group × genotype interactions (all p < 0.05). The posthoc analysis revealed that, in comparison with nonlong COVID, long COVID increased lactic acid concentrations in Nordic walking sessions in CC and CT genotypes (all p < 0.05). Physical therapy strategy through Nordic walking enhanced physical capabilities during aerobic exercise in post-COVID19 patients with different genotypes in ACTN3 c.1729C>T and AMPD1 c.34C>T polymorphisms. These findings suggest that individuals who reported long COVID who presumably exercised less beforehand appeared to be less able to exercise, based on lactate levels, and the effect of aerobic physical exercise enhanced physical capabilities conditioned by several genetic markers in long COVID patients.

Clinical Spectrum of Long COVID: Effects on Female Reproductive Health

The COVID-19 pandemic caused by SARS-CoV-2 has presented numerous health challenges, including long-term COVID, which affects female reproductive health. This review consolidates the current research on the impact of SARS-CoV-2 on the menstrual cycle, ovarian function, fertility, and overall gynecological health. This study emphasizes the role of angiotensin-converting enzyme receptors in viral entry and the subsequent tissue-specific pathological effects. It also explores the potential influence of long COVID on hormonal balance and immune responses, contributing to menstrual irregularities and impaired ovarian function. The findings indicate a higher prevalence of long-term COVID-19 among women, highlighting the substantial implications for reproductive health and the need for sex-sensitive longitudinal studies. Enhanced surveillance and targeted research are essential to develop effective interventions that prioritize women's reproductive well-being following SARS-CoV-2 infection. This review advocates for a sex-informed approach to ongoing COVID-19 research and healthcare strategies, aiming to provide up-to-date and pertinent data for healthcare providers and the general public, ultimately improving outcomes for females affected by long COVID.

Physical Health in Patients with Post-COVID-19 6 and 12 Months after an Inpatient Rehabilitation: An Observational Study

Background: Rehabilitation is an effective and feasible approach for post-COVID patients to improve physical health. However, knowledge regarding the long-term impact of rehabilitation on the physical health of these patients is lacking. Methods: Changes in physical health of 127 patients with COVID-19 as an occupational disease or work accident were assessed in a longitudinal observational study. Post-COVID symptoms, functional status, functional exercise capacity, endurance capacity, physical performance, quadricep strength, handgrip strength, motor balance ability, and self-reported physical performance were examined at the beginning as well as 6 and 12 months after the rehabilitation. Group differences concerning sex, age, acute COVID status, comorbidities prior to COVID-19, and aftercare interventions were also analysed. Results: Even 12 months after rehabilitation, the prevalence of post-COVID symptoms (28.6-94.7%) remained remarkably high in the study population. Significant improvements in various aspects of physical health were observed 6 (r = 0.288-0.755) and 12 months (r = 0.189-0.681) after the rehabilitation. Participants demonstrated enhanced endurance, strength, and balance function, as well as improvement in subjective physical ability. Significant group differences were observed between younger and older patients, those with mild-moderate and severe-critical COVID-19, and patients with and without pre-existing cardiovascular disease, metabolic disease, psychological disease, neuro-sensory disease, musculoskeletal disease, and exercising in an outpatient group. Conclusions: The study identifies persistent challenges in COVID-19 recovery, despite significant improvements in physical health 6 and 12 months after rehabilitation. Further research and the implementation of standardised approaches are required to enhance the outcomes of post-COVID rehabilitation, with a focus on developing personalised care strategies for long-term recovery.

Clinical and Physiological Variables in Patients with Post-COVID-19 Condition and Persistent Fatigue

Background/Objectives: Post-COVID-19 condition can manifest through various symptoms such as dyspnea, cognitive disturbances, and fatigue, with mechanisms related to these symptoms, particularly those related to fatigue, still requiring further clarification. Therefore, our aim was to assess the clinical and physiological variables in patients with post-COVID-19 condition and persistent fatigue. Methods: After one year post-COVID-19 infection, the patients underwent a comprehensive evaluation, including a complete blood count, a metabolic panel, complete spirometry, and assessments of dyspnea, quality of life, anxiety and depression, physical capacity, body composition, muscle strength, comorbidities, and medications. The participants were categorized into two groups: G1-fatigue and G2-non-fatigue. Results: Seventy-seven patients (53% female; 55 ± 11.8 years) were included, 37 in G1 and 40 in G2. As for clinical markers and symptoms of illness, in those with persistent fatigue symptoms, a greater sensation of dyspnea [BDI score: 7.5 (6-9) vs. 12 (9-12), p < 0.001; mMRC score: 1 (1-2) vs. 0 (0-1), p = 0.002], worse quality of life [SGRQ total score: 1404 (1007-1897) vs. 497 (274-985); p < 0.001], higher levels of anxiety [HADS-A score: 8 (5-9) vs. 3 (0.5-4); p < 0.001], and a reduction in peripheral and inspiratory muscle strength [handgrip strength: 34 (28-40) vs. 40 (30-46.5) kgf, p = 0.044; MIP: -81 ± 31 vs. -111 ± 33 mmHg, p < 0.001)] were observed. Conclusions: Those with persistent fatigue exhibited a greater sensation of dyspnea, higher levels of anxiety, reduced peripheral and inspiratory muscle strength, and a greater impairment of quality of life. The severity of fatigue was influenced by the worsening quality of life, heightened anxiety levels, and decreased peripheral muscle strength. Additionally, the worse quality of life was associated with a higher sensation of dyspnea, lower muscle strength, and reduced physical capacity.

Evaluation of Serial Procalcitonin Levels for the Optimization of Antibiotic Use in Non-Critically Ill COVID-19 Patients

BACKGROUND

Procalcitonin (PCT) has been used as a biomarker to guide antibiotic therapy in various patient populations. However, its role in optimizing antibiotic use in COVID-19 patients has not been well studied to date. Thus, we aimed to evaluate the use of serial PCT monitoring as an antimicrobial stewardship tool for COVID-19 patients.

METHODS

This retrospective study included 240 COVID-19 patients who were admitted to a tertiary medical institution in Saudi Arabia between January 2020 and February 2022. Patients who received empiric antibiotic therapy for community-acquired pneumonia (CAP) and had serial procalcitonin levels were included. The patients were divided into two groups: the normal procalcitonin arm (PCT level < 0.5 ng/mL) and the elevated PCT arm (PCT level > 0.5 ng/mL). The primary and secondary outcomes were the effect of PCT monitoring on the duration of antibiotic exposure and the length of hospital stay, respectively. To measure the accuracy of PCT, the receiver-operating characteristic area under the curve (ROC-AUC) was determined.

RESULTS

Among the included patients, 142 were in the normal procalcitonin arm (median PCT, 0.12 ng/mL), and 78 were in the elevated PCT arm (median PCT, 4.04 ng/mL). The baseline characteristics were similar between the two arms, except for the higher prevalence of kidney disease in the elevated PCT arm. There was no statistically significant difference in the duration of antibiotic exposure between the normal and elevated PCT arms (median duration: 7 days in both arms). However, the length of hospital stay was significantly shorter in the normal PCT arm (median stay, 9 days) than in the elevated PCT arm (median stay, 13 days; p = 0.028). The ROC-AUC value was 0.54 (95% CI: 0.503-0.595).

CONCLUSIONS

Serial PCT monitoring did not lead to a reduction in the duration of antibiotic exposure in COVID-19 patients. However, it was associated with a shorter hospital stay. These findings suggest that PCT monitoring may be useful for optimizing antibiotic use and improving outcomes in COVID-19 patients. While PCT-guided algorithms have the potential to enable antibiotic stewardship, their role in the context of COVID-19 treatment requires further investigation.

Effects of Hyperbaric Oxygen Therapy on Long COVID: A Systematic Review

The coronavirus disease (COVID-19) pandemic has resulted in an increasing population that is experiencing a wide range of long-lasting symptoms after recovery from the acute infection. Long COVID refers to this specific condition and is associated with diverse symptoms, such as fatigue, myalgias, dyspnea, headache, cognitive impairment, neurodegenerative symptoms, anxiety, depression, and a sense of despair. The potential of hyperbaric oxygen therapy (HBOT) to improve chronic fatigue, cognitive impairments, and neurological disorders has been established; therefore, the use of HBOT to treat long COVID has also been studied. We conducted a literature search between 1 January 2019 and 30 October 2023, focusing on the clinical efficacy and utility of HBOT for treating long COVID and found ten clinical studies that fit the review topic, including one case report, five one-group pretest-posttest design studies, one safety report from a randomized controlled trial (RCT), and three complete reports of RCTs. Most studies found that HBOT can improve quality of life, fatigue, cognition, neuropsychiatric symptoms, and cardiopulmonary function. Although HBOT has shown some benefits for long COVID symptoms, further rigorous large-scale RCTs are required to establish precise indications, protocols, and post-treatment evaluations.

Long COVID outcomes following omicron wave in non-hospital population

Background

The persistence of symptoms or the development of new symptoms following a diagnosis of SARS-CoV-2 has given rise to a multifaceted clinical condition referred to as "long COVID" (LC). The understanding of LC among China's non-hospitalized population continues to be insufficient. This investigation was designed to evaluate the protracted consequences amongst this demographic, as well as to identify the associated risk factors.

Methods

This research constitutes a prospective cohort study focusing on non-hospitalized individuals, aged between 18 and 59, who have been positively diagnosed with COVID-19. Each participant was subjected to a sequence of questionnaire-based surveys, designed to evaluate symptoms as well as the status of depression and anxiety. A logistic regression model, adjusted for multiple variables, was employed to scrutinize the correlation between demographic elements, lifestyle attributes, and health-related risk factors in relation to conditions and symptoms post COVID-19 infection.

Results

A total of 706 individuals participated in the 3 months follow-up, with 620 continuing on to the 6 months follow-up. The median age was 35 (28, 43) years, and 597 (85%) are female. Upon follow-up, Compared with patients without LC, patients with LC have a higher proportion of females (420 (87%) vs. 177 (79%); p = 0.010), were older (35 (29, 44) years vs. 33 (27, 41) years; p = 0.010) and have more comorbidities. Out of all participants, 483 (68.4%) reported experiencing at least one symptom at the 3 months mark, while 49.7% reported symptoms persisting at the 6 months mark. At the 3 months follow-up, the most prevalent persistent symptoms were cough (46%), fatigue (38%), and shortness of breath (34%). By the 6 months follow-up, fatigue (25%), shortness of breath (22%), and sleep disorders (16%) were the most commonly reported symptoms. Anxiety and depression were consistently reported as prevalent symptoms throughout the follow-up period. Most patient symptoms fade over time, with the quickest decreases observed in cough (from 46 to 9%), expectoration (from 26 to 6.3%), smell disorder (from 16 to 3.9%), and taste disorder (from 18 to 3.5%). Male and those possessing advanced educational qualifications exhibit a decreased susceptibility to the sustained incidence of coughing. Conversely, older age and the presence of comorbidities were identified as risk factors for persistent fatigue and shortness of breath.

Conclusion

In the after of COVID-19, it has been observed that the majority of patient symptoms tend to decrease over time. The primary residual symptoms noticed after a 6 month follow-up were fatigue, dyspnea, and sleep disturbances. However, it's noteworthy that the risk factors associated with these symptoms exhibit subtle variations. Furthermore, psychological sequelae, namely depression and anxiety, are frequently reported among COVID-19 survivors.

Predictive Factors and ACE-2 Gene Polymorphisms in Susceptibility to Long COVID-19 Syndrome

Long COVID-19 syndrome is present in 5-10% of patients infected with SARS-CoV-2, and there is still little information on the predisposing factors that lead to its development. The purpose of the study was to evaluate the predictive factors in early symptoms, clinical features and the role of Angiotensin-Converting Enzyme-2 (ACE-2) c.513-1451G>A (rs2106806) and c.15643279T>C (rs6629110) polymorphisms in the susceptibility to developing Long COVID-19 syndrome subsequent to COVID-19 infectionA total of 29 patients who suffered COVID-19 were recruited in a descriptive longitudinal study of two groups: Long COVID-19 (n = 16) and non-Long COVID-19 (n = 13). Early symptoms and clinical features during COVID-19 were classified by a medical service. ACE-2 polymorphisms were genotyped by using a Single Nucleotide Primer Extension (SNPE). Of the early symptoms, fatigue, myalgia and headache showed a high risk of increasing Long COVID-19 susceptibility. Clinical features such as emergency care, SARS-CoV-2 reinfection, previous diseases, respiratory disease and brain fog also had a high risk of increasing Long COVID-19 susceptibility. The A allele in the rs2106806 variant was associated with an odds ratio (OR) of 4.214 (95% CI 2.521-8.853; p < 0.001), and the T allele in the rs6629110 variant was associated with an OR of 3.754 (95% CI 1.785-6.105; p = 0.002) of increasing Long COVID-19 susceptibility. This study shows the risk of ACE-2 polymorphisms, different early symptoms and clinical features during SARS-CoV-2 infection in susceptibility to Long COVID-19.