Long COVID: An overview

Clinical characteristics of female long COVID patients with menstrual symptoms: a retrospective study from a Japanese outpatient clinic

PURPOSE

To elucidate the impact of long COVID on menstruation and mental health, medical records of patients with long COVID were evaluated.

METHODS

Symptoms of long COVID, QOL, mental health, and related endocrine data were compared between two groups with and without menstrual disturbances.

RESULTS

Of 349 female patients who visited our clinic between February 2021 and March 2023, 223 patients with long COVID (aged 18-50 years) were included. Forty-four (19.7%) of the patients had menstrual symptoms associated with long COVID. The patients with menstrual symptoms were older than those without menstrual symptoms (42.5 vs. 38 years). The percentage of patients with menstrual symptoms was higher during the Omicron phase (24%) than during the Preceding (13%) and Delta (12%) phases. Cycle irregularity was the most frequent (in 63.6% of the patients), followed by severe pain (25%), heavy bleeding (20.5%), perimenopausal symptoms (18.2%), and premenstrual syndrome (15.9%). Fatigue and depression were the most frequent complications. Scores for fatigue and for QOL were significantly worse in long COVID patients with menstrual symptoms. Results of endocrine examinations showed significantly increased cortisol levels in patients with menstrual complaints.

CONCLUSION

Long COVID has an impact on menstrual conditions and on QOL related to menstrual conditions.

Neurocognitive and psychiatric outcomes associated with postacute COVID-19 infection without severe medical complication: a meta-analysis

BACKGROUND

Cognitive symptoms are often reported by those with a history of COVID-19 infection. No comprehensive meta-analysis of neurocognitive outcomes related to COVID-19 exists despite the influx of studies after the COVID-19 pandemic. This study meta-analysed observational research comparing cross-sectional neurocognitive outcomes in adults with COVID-19 (without severe medical/psychiatric comorbidity) to healthy controls (HCs) or norm-referenced data.

METHODS

Data were extracted from 54 studies published between January 2020 and June 2023. Hedges' g was used to index effect sizes, which were pooled using random-effects modelling. Moderating variables were investigated using meta-regression and subgroup analyses.

RESULTS

Omnibus meta-analysis of 696 effect sizes extracted across 54 studies (COVID-19 n=6676, HC/norm-reference n=12 986; average time since infection=~6 months) yielded a small but significant effect indicating patients with COVID-19 performed slightly worse than HCs on cognitive measures (g=-0.36; 95% CI=-0.45 to -0.28), with high heterogeneity (Q=242.30, p<0.001, τ=0.26). Significant within-domain effects was yielded by cognitive screener (g=-0.55; 95% CI=-0.75 to -0.36), processing speed (g=-0.44; 95% CI=-0.57 to -0.32), global cognition (g=-0.40; 95% CI=-0.71 to -0.09), simple/complex attention (g=-0.38; 95% CI=-0.46 to -0.29), learning/memory (g=-0.34; 95% CI=-0.46 to -0.22), language (g=-0.34; 95% CI=-0.45 to -0.24) and executive function (g=-0.32; 95% CI=-0.43 to -0.21); but not motor (g=-0.40; 95% CI=-0.89 to 0.10), visuospatial/construction (g=-0.09; 95% CI=-0.23 to 0.05) and orientation (g=-0.02; 95% CI=-0.17 to 0.14). COVID-19 samples with elevated depression, anxiety, fatigue and disease severity yielded larger effects.

CONCLUSION

Mild cognitive deficits are associated with COVID-19 infection, especially as detected by cognitive screeners and processing speed tasks. We failed to observe clinically meaningful cognitive impairments (as measured by standard neuropsychological instruments) in people with COVID-19 without severe medical or psychiatric comorbidities.

Profiles of objective and subjective cognitive function in Post-COVID Syndrome, COVID-19 recovered, and COVID-19 naïve individuals

Post-COVID Syndrome has emerged as a significant public health concern worldwide with increasing evidence to suggest that individuals who have had an acute COVID-19 infection report lingering memory and attention difficulties, even in individuals who have fully recovered and no longer experiencing symptoms of COVID-19. The present study sought to investigate the profile of objective and subjective cognitive difficulties in people who have Post-COVID Syndrome, people who have fully recovered from an acute COVID infection and people who have never had COVID-19. We further sought to explore the extent to which self-reported fatigue and stress are related to subjective and objective cognitive difficulties. 162 participants including 50 people living with Post-COVID Syndrome, 59 people who have had COVID-19 but have fully recovered and 53 people who have never experienced symptoms of COVID-19 and had never tested positive for COVID-19 were recruited from Academic Prolific to complete a series of online questionnaires and neurocognitive tasks. Subjective cognitive function was measured using the Cognitive Failures Questionnaire and objective cognitive function was measured using the Cognitron cognitive test battery. We found that objective and subjective measures of cognitive function were not significantly related, suggesting that self-reports of "brain fog" are not reflecting objectively measured cognitive dysfunction. A MANOVA revealed that subjective cognitive deficits were driven by heightened perceived stress and fatigue and not significantly related to COVID-19 status. Objective cognitive function, however, was significantly related to perceived stress and COVID status whereby we observed significant objective cognitive deficits in people who have been exposed to an acute COVID-19 infection regardless of whether they had Post-COVID Syndrome or had fully recovered, as compared to people who had never had COVID-19. This suggests that an acute infection can have long term effects on cognitive function, even without persistent COVID-19 symptoms. Encouragingly, objective cognitive function was significantly associated with time since initial infection showing that cognitive deficits improved over time for people who had recovered from COVID-19. However, we did not observe the same improvement in individuals with Post-COVID Syndrome and observed that cognitive dysfunction was significantly related to the number of neurological symptoms presently experienced. These results add to the accumulating literature that COVID-19 is associated with significant cognitive difficulties following a COVID-19 infection, which appear to improve over time for those who have recovered from COVID-19 yet persist in people living with Post-COVID Syndrome.

Investigating the trajectory of post-COVID impairments: a longitudinal study in Sweden

Introduction

Individuals recovering from COVID-19 often experience a range of post-recovery symptoms. However, the literature on post-COVID-19 symptoms reveals conflicting results, necessitating a heightened focus on longitudinal studies to comprehend the trajectory of impairments over time. Our study aimed to investigate changes in long-term impairments among individuals infected with COVID-19 and explore potential predictors influencing these changes.

Methods

We conducted a web-survey targeting individuals that had been infected with COVID-19 at four time-points: T0 (baseline), T1 (three months), T2 (six months), and T3 (twelve months). The survey included contextual factors, factors related to body functions and structures, and post-COVID impairments. The longitudinal sample included 213 individuals (with a mean age of 48.92 years). Linear mixed models were employed to analyze changes in post-COVID impairments over time and identify impacting factors.

Results

Findings revealed a general decline in post-COVID impairments over time, with each symptom exhibiting a dynamic pattern of fluctuations. Factors such as initial infection severity, education level, and work status were significantly associated with the levels of impairments.

Discussion

The study emphasizes that post-COVID impairments are not static but exhibit variations over time. Personalized care, especially for vulnerable populations, is crucial. The results underscore the need for long-term monitoring and multidisciplinary treatment approaches. Targeted support and interventions are highlighted for individuals with severe initial infections and those in socioeconomically disadvantaged groups.

The Prevalence of Post-Acute Sequelae of COVID-19 in Solid Organ Transplant Recipients: Evaluation of Risk in the National COVID Cohort Collaborative (N3C)

Post-acute sequelae after COVID-19 (PASC) is increasingly recognized, though data in solid organ transplant recipients (SOTR) are limited. Using the N3C, we performed 1:1 propensity score matching (PSM) of all adult SOTR and non-immunosuppressed/immunocompromised (ISC) patients with acute COVID (08-01-2021 to 01-13-2023), for a subsequent PASC diagnosis using ICD-10-CM codes. Multivariable logistic regression was used to examine the association of SOT status with PASC, but also other patient factors after stratifying by SOT status. Prior to PSM, there were 8,769 SOT and 1,576,769 non-ISC patients with acute COVID. After PSM, 8,756 SOTR and 8,756 non-ISC patients were included; 2.2% of SOTR (n=192) and 1.4% (n=122) of non-ISC patients developed PASC (p-value<0.001). In the overall matched cohort, SOT was independently associated with PASC (aOR 1.48, 95% CI 1.09-2.01). Amongst SOTR, COVID severity (aOR 11.6, 95% CI 3.93-30.0 for severe versus mild disease), older age (aOR 1.02, 95% CI 1.01-1.03 per year), and mycophenolate mofetil use (aOR 2.04, 95% CI 1.38-3.05) were each independently associated with PASC. In non-ISC patients, only depression (aOR 1.96, 95% CI 1.24-3.07) and COVID severity were. In conclusion, PASC occurs more commonly in SOTR than non-ISC patients, with differences in risk profiles based on SOT status.

Incidence of post-COVID psychiatric disorders according to the periods of SARS-CoV-2 variant dominance: The LIFE study

This retrospective cohort study examined the incidence of post-COVID psychiatric disorders in older adults according to hospitalization status and SARS-CoV-2 variant period in Japan. Claims data, COVID-19 case-related information, and vaccination records were obtained from three Japanese municipalities. We identified individuals aged ≥65 years who had COVID-19 or other respiratory tract infection (RTI) between March 2021 and December 2022. Participants were categorized into non-hospitalized and hospitalized patients, and the study period was divided into the Alpha (March to May 2021), Delta (June to December 2021), Omicron BA.1/BA.2 (January to June 2022), and Omicron BA.5 (July to December 2022) periods. Modified Poisson regression analyses were performed to estimate the incidence rate ratios (IRRs) for the occurrence of psychiatric disorders (organic mental disorders, psychotic disorders, mood disorders, anxiety disorders, and insomnia) three months after COVID-19 (reference: other RTI). For overall psychiatric disorders, we analyzed 19,489 non-hospitalized patients (COVID-19: 6,728, Other RTI: 12,761) and 2925 hospitalized patients (COVID-19: 1,036, Other RTI: 1889). When compared with other RTI cases, COVID-19 cases had significantly lower IRRs for overall psychiatric disorders in both non-hospitalized (IRR: 0.59, P < 0.001) and hospitalized cases (IRR: 0. 83, P = 0.045) during the Omicron BA.1/BA.2 period, but only in non-hospitalized cases (IRR: 0.45, P < 0.001) during the Omicron BA.5 period. The incidences of the individual post-COVID psychiatric disorders varied according to disorder type, hospitalization status, and SARS-CoV-2 variant period. These findings provide a foundation for further research to explore these variations and improve the provision of psychiatric care in future epidemics.

Exploring the Experiences of Living With the Post-COVID Syndrome: A Qualitative Study

INTRODUCTION

Many people experience persistent symptoms for more than 12 weeks following SARS-CoV-2 infection, which is known as post-COVID-19 condition (PCS) or Long COVID (LC). PCS can impair people's quality of life and daily functioning. However, there is a lack of in-depth research exploring the PCS patient journey, as well as gendered aspects of patients' experiences.

METHODS

Nineteen semi-structured qualitative interviews were conducted with people living with PCS in the United Kingdom (13 women, 6 men). Interviews were transcribed verbatim and analysed inductively using reflexive thematic analysis.

RESULTS

Five main themes were identified: 'Symptom dismissal', 'Lack of information and support', 'Life before and after Long COVID', 'Psychological impact' and 'Acceptance'. A shift overtime to self-management of symptoms was evident. These themes represent different stages of patients' PCS journey. Narratives indicated that women highlighted dismissal by healthcare professionals (HCPs), which was not as prominent in men's narratives. In addition, women went into more detail about the psychological impact of PCS compared to men.

CONCLUSION

Women with PCS reported symptom dismissal by HCPs, which may have delayed their diagnosis and negatively affected their well-being. We were not able to explore the experiences of people from non-conforming gender groups. Raising awareness of these issues among HCPs, particularly general practitioners, could improve patient care in PCS.

PATIENT OR PUBLIC CONTRIBUTION

Patient and public involvement consisted of people who took part in the interviews and commented on the themes' interpretation and study conclusions.

Role of self-esteem and personal mastery on the association between social support and resilience among COVID-19 long haulers

Although the COVID-19 mortality rate is declining, the number of individuals dealing with persistent COVID-19 symptoms is increasing worldwide, making long COVID a global public health concern. People with long COVID (long haulers) often deal with physical and mental stressors. Long haulers' psychological resilience could play a key role in coping with these stressors in intercorrelation with psychosocial resources. The current study aims to test a hypothesized relationship between social support and its functions (i.e., instrumental and emotional) and the resilience of long haulers through serial mediation by personal mastery and self-esteem. A cross-sectional and self-administered online survey was conducted among 460 individuals with long COVID recruited from COVID-19 Facebook support groups in the United States. Analyzing data indicated a positive correlation between social support and the resilience of long haulers. Structural equation modeling suggested that self-esteem and personal mastery fully mediated the association between social (instrumental) support and resilience. Personal mastery also mediated the association between self-esteem and resilience in social (instrumental) support models. However, in the emotional support model, the indirect effect was non-significant for the mediation by personal mastery and self-esteem. Findings suggest that social support, mainly instrumental support, may protect long haulers by promoting their resilience through self-esteem and personal mastery. This study emphasizes the importance of including social support services in designing programs for COVID-19 long haulers.

Needs and Demands for e-Health Symptom Management Interventions in Patients with Post-COVID-19 Condition: A User-Centered Design Approach

Introduction: Post-COVID-19 is an increasing chronic disease for which potential treatment options require further development and examination. A well-established approach to symptom management in post-COVID-19 patients could be e-Health interventions. To enhance the implementation and utilization of e-Health interventions, the needs and demands of patients should be taken into consideration. The aim of this study was to investigate needs and demands of post-COVID-19 patients concerning e-Health symptom management interventions. Methods: A total of 556 patients participated in this cross-sectional online survey study. Recruitment was performed from January 19 to May 24, 2022. Data related to the needs and demands for e-Health interventions were analyzed, along with medical and sociodemographic information. Results: The majority of the patients preferred interventions accessible on smartphones (95.3%). The favored content formats were applications (82.7%), interactive training (69.3%), or audio and video materials (61.1%). Furthermore, the preferred session length was about 10-20 min. The most desired topics included "quality of life," "information about how intensively I may exert myself or do sports," "adjustment to new life situation," and "handling physical changes." Conclusions: This study provides a detailed framework for the content and design of e-Health interventions to support patients managing their post-COVID-19 symptoms. The findings could significantly influence the further development of tailored e-Health interventions to address this pressing global health concern.

Identifying Post-Acute Sequelae of SARS-CoV-2 Among Children in New York State Medicaid Managed Care

Persons who contract COVID-19 are at risk of developing post-acute sequelae of SARS-CoV-2 (PASC). The objective of this study was to describe the incidence of PASC in a pediatric Medicaid population. Using a retrospective cohort of children enrolled in New York State Medicaid Managed Care we compared incident diagnoses between children with a positive laboratory test for SARS-CoV-2 in 2021 to children without a positive test in 2021 and children with a viral respiratory diagnosis in 2019. Logistic regression models estimated adjusted odds ratios using the Cohen's d statistic to assess the strength of associations. Most unadjusted incidence of clinical outcomes were less than 1% for all cohorts. Relative to the 2021 comparison cohort, significant increases among SARS-CoV-2 cases were observed in sequela of infectious disease conditions, general signs and symptoms, and pericarditis and pericardial disease and for the 2019 comparison, sequela of infectious disease conditions and suicidal ideation. However, associations were mostly determined to be weak or marginal. In this low socioeconomic status pediatric population, incidence of new clinical sequelae was low with mostly weak or marginal increases associated with SARS-CoV-2 infection. Though the incidence was low, some outcomes may be severe. Observed associations may have been impacted by pandemic behavior modification including social distancing policies.

The Review of Ophthalmic Symptoms in COVID-19

The COVID-19 pandemic caused by SARS-CoV-2 had a significant impact on the health of the global human population, affecting almost every human organ, including the organ of vision. Research focus on understanding the pathophysiology, identifying symptoms and complications of the disease. Eye-related pathologies are important foci of research due to the potential for direct impact of the virus. Ophthalmologists around the world are reporting various symptoms of eye infections and ocular pathologies associated with SARS-CoV-2. The review of ophthalmic symptoms was conducted to help physicians of various specialties recognize possible ophthalmic manifestations of this viral disease. A literature review was conducted from January 2020 to July 2023 in the PubMed, MEDLINE, Science Direct, Scopus, Scielo and Google Scholar databases. The review of the literature showed that conjunctivitis is the most common ophthalmic symptom observed during the course of COVID-19 and can occur at any stage of the disease. Changes in the eye may result from the direct effect of the virus, immune response, prothrombotic states, comorbidities, and medications used. Symptoms related to the organ of vision can be divided into: changes affecting the protective apparatus of the eye, the anterior eye segment, the posterior eye segment, neuro-ophthalmic, and orbital changes. Ocular symptoms may suggest COVID-19 infection or appear several weeks after recovery. Following COVID-19 vaccinations, a diverse range of ophthalmic symptoms was observed in various locations and at different times, mirroring the ocular symptoms experienced throughout the course of the COVID-19 illness. It is important for physicians of all specialties to be aware of possible potential connections between eye diseases and SARS-CoV-2, in order to effectively diagnose and treat patients.

Optimizing cardiopulmonary rehabilitation duration for long COVID patients: an exercise physiology monitoring approach

The presence of prolonged symptoms after COVID infection worsens the workability and quality of life. 200 adults with long COVID syndrome were enrolled after medical, physical, and mental screening, and were divided into two groups based on their performance. The intervention group (n = 100) received supervised rehabilitation at Department of Pulmonology, Semmelweis University with the registration number 160/2021 between 01/APR/2021-31/DEC/2022, while an age-matched control group (n = 100) received a single check-up. To evaluate the long-term effects of the rehabilitation, the intervention group was involved in a 2- and 3-month follow-up, carrying out cardiopulmonary exercise test. Our study contributes understanding long COVID rehabilitation, emphasizing the potential benefits of structured cardiopulmonary rehabilitation in enhancing patient outcomes and well-being. Significant difference was found between intervention group and control group at baseline visit in pulmonary parameters, as forced vital capacity, forced expiratory volume, forced expiratory volume, transfer factor for carbon monoxide, transfer coefficient for carbon monoxide, and oxygen saturation (all p < 0.05). Our follow-up study proved that a 2-week long, patient-centered pulmonary rehabilitation program has a positive long-term effect on people with symptomatic long COVID syndrome. Our data showed significant improvement between two and three months in maximal oxygen consumption (p < 0.05). Multidisciplinary, individualized approach may be a key element of a successful cardiopulmonary rehabilitation in long COVID conditions, which improves workload, quality of life, respiratory function, and status of patients with long COVID syndrome.

Examining Well-Being and Cognitive Function in People with Long COVID and ME/CFS, and Age-Matched Healthy Controls: A Case-Case-Control Study

BACKGROUND

Well-being and cognitive function had not previously been compared between people with long COVID and people with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Therefore, this study examined well-being and cognitive function in people with long COVID (∼16 months illness duration; n = 17) and ME/CFS (∼16 years illness duration; n = 24), versus age-matched healthy controls (n = 16).

METHODS

Well-being was examined using several questionnaires, namely the Health Visual Analogue Scale (VAS), Fatigue Severity Scale (FSS), post-exertional malaise (PEM), Pittsburgh Sleep Quality Index (PSQI), European Quality of Life-5 Domains (EQ-5D), MRC Dyspnoea, Self-Efficacy (SELTC), The Edinburgh Neurosymptoms Questionnaire (ENS), General Anxiety Disorder 7 (GAD-7) and Patient Health Questionnaire 9 (PHQ-9). Cognitive function was examined using Single Digit Modalities Test (SDMT), Stroop test and Trails A and B. These were delivered via a mobile application (app) built specifically for this remote data collection.

RESULTS

The main findings of the present investigation were that people with ME/CFS and people with long COVID were generally comparable on all well-being and cognitive function measures, but self-reported worse values for pain, fatigue, post-exertional malaise, sleep quality, general well-being in relation to mobility, usual activities, self-care, breathlessness, neurological symptoms, self-efficacy and other well-being such as anxiety and depression, compared to controls. There was no effect of group for cognitive function measures.

CONCLUSIONS

These data suggest that both people with long COVID and people with ME/CFS have similar impairment on well-being measures examined herein. Therefore, interventions that target well-being of people with ME/CFS and long COVID are required.

Navigating Public Policy Responses to a Pandemic: The Balancing Act Between Physical Health, Mental Health, and Household Income

OBJECTIVE

During COVID-19, governments imposed restrictions that reduced pandemic-related health risks but likely increased personal and societal mental health risk, partly through reductions in household income. This study aimed to quantify the public's willingness to accept trade-offs between pandemic health risks, household income reduction, and increased risk of mental illness that may result from future pandemic-related policies.

METHODS

A total of 547 adults from an online panel participated in a discrete choice experiment where they were asked to choose between hypothetical future pandemic scenarios. Each scenario was characterized by personal and societal risks of dying from the pandemic, experiencing long-term complications, developing anxiety/depression, and reductions in household income. A latent class regression was used to estimate trade-offs.

RESULTS

Respondents state a willingness to make trade-offs across these attributes if the benefits are large enough. They are willing to accept 0.8% lower household income (0.7-1.0), 2.7% higher personal risk of anxiety/depression (1.8-3.6), or 3.2% higher societal rate of anxiety/depression (1.7-4.7) in exchange for 300 fewer deaths from the pandemic.

CONCLUSION

Results reveal that individuals are willing to accept lower household income and higher rates of mental illness, both personal and societal, if the physical health benefits are large enough. Respondents placed greater emphasis on maintaining personal, as opposed to societal, mental health risk and were most interested in preventing pandemic-related deaths. Governments should consider less restrictive policies when pandemics have high morbidity but low mortality to avoid the prospect of improving physical health while simultaneously reducing net social welfare.

Patients With Post-COVID-19 Respiratory Condition: Chest Computed Tomography Findings and Pulmonary Function Tests and Comparison With Asymptomatic Participants

OBJECTIVE

The aims of this study were to assess the chest computed tomography (CT) findings in post-COVID-19 respiratory condition (rPCC) patients and compare the findings with asymptomatic participants (APs). It also aimed to evaluate the relationship between CT findings and pulmonary function tests (PFTs) in rPCC patients. Finally, it aimed to compare the quantitative chest CT findings and PFT results of patients with rPCC and APs.

METHODS

We retrospectively enrolled consecutive patients with rPCC who underwent unenhanced chest CT and PFTs between June 2020 and September 2022. In addition, a control group (APs) was prospectively formed and underwent nonenhanced chest CT and PFTs. The presence and extent of abnormalities in unenhanced chest CT images were evaluated qualitatively and semiquantitatively in a blinded manner. We used fully automatic software for automatic lung and airway segmentation and quantitative analyses.

RESULTS

Sixty-three patients with rPCC and 23 APs were investigated. Reticulation/interstitial thickening and extent of parenchymal abnormalities on CT were significantly greater in the rPCC group than in the control group ( P = 0.001 and P = 0.004, respectively). Computed tomography extent score was significantly related to length of hospital stay, age, and intensive care unit stay (all P s ≤ 0.006). The rPCC group also had a lower 85th percentile attenuation lung volume ( P = 0.037). The extent of parenchymal abnormalities was significantly correlated with carbon monoxide diffusing capacity ( r = -0.406, P = 0.001), forced vital capacity (FVC) ( r = -0.342, P = 0.002), and forced expiratory volume in 1 second/FVC ( r = 0.427, P < 0.001) values. Pulmonary function tests revealed significantly lower carbon monoxide diffusing capacity ( P < 0.001), FVC ( P = 0.036), and total lung capacity ( P < 0.001) values in the rPCC group.

CONCLUSIONS

The rPCC is characterized by impaired PFTs, a greater extent of lung abnormalities on CT, and decreased 85th percentile attenuation lung volume. Advanced age, intensive care unit admission history, and extended hospital stay are risk factors for chest CT abnormalities.

Confirmation of COVID-19 infection status and reporting of Long COVID symptoms in a population-based birth cohort: No evidence of a nocebo effect

Some patients with COVID-19 develop symptoms after the acute infection, known as 'Long COVID'. We examined whether or not confirmation of COVID-19 infection status could act as a nocebo, using data from questionnaires distributed to the Avon Longitudinal Study of Parents and Children cohort. We examined associations between confirmation of COVID-19 infection status (confirmed by a positive test vs unconfirmed) and reporting of Long COVID symptoms. We explored the roles of sex and anxiety as potential moderators. There was no clear evidence of a strong association between confirmation of COVID-19 infection status and the Long COVID composite score, physical or psychological symptoms or duration of symptoms. There was no clear evidence of moderation by sex or anxiety. We therefore found no evidence of a nocebo effect. Our data suggest that this psychological mechanism does not play a role in the medical symptomatology experienced by patients with Long COVID.

Navigating the Long Haul: A Comprehensive Review of Long-COVID Sequelae, Patient Impact, Pathogenesis, and Management

Long COVID, characterized by persistent symptoms following a SARS-CoV-2 infection, presents a significant public health challenge with wide-ranging implications. This comprehensive review explores the epidemiology, clinical manifestations, pathogenesis, risk factors, diagnosis, patient impact, management strategies, and long-term prognosis of COVID. Despite a varied symptomatology that spans multiple organ systems, including respiratory, neurological, and cardiovascular systems, this condition is primarily associated with chronic inflammation and potential viral persistence. Prevalence varies, influenced by the initial infection severity, demographic factors, and pre-existing conditions. The review emphasizes the necessity for healthcare systems to adapt to the needs of long-COVID patients by developing standardized diagnostic criteria and personalized, multidisciplinary treatment approaches. Current research gaps and future directions are identified, highlighting the urgent need for further studies on pathophysiological mechanisms and effective therapeutic interventions. This review aims to inform healthcare providers, researchers, and policymakers, enhancing patient care and guiding ongoing and future research initiatives. The continuing global focus and collaborative efforts offer hope for improved outcomes for those affected by long COVID, marking an essential step towards addressing this emergent condition comprehensively.

Unmasking Bartonella henselae infection in the shadows of long COVID thanks to clinical metagenomics

The diagnosis of long COVID often relies on symptoms post-COVID-19, occasionally lacking biological evidence. This case study illustrates how investigating long COVID uncovered an underlying bartonellosis through clinical metagenomics. Following mild COVID-19, a 26-year-old woman experienced persistent symptoms during 5 months, including axillary adenopathy. Pathological examination, 16 S rRNA PCR, and clinical metagenomic analysis were done on an adenopathy biopsy. The latter revealed Bartonella henselae DNA and RNA. Treatment with clarithromycin improved symptoms. This case underscores the relevance of clinical metagenomics in diagnosing hidden infections. Post-COVID symptoms warrant thorough investigation, and bartonellosis should be considered in polyadenopathy cases, regardless of a recent history of cat or flea exposures.

Redox Biomarkers - An Effective Tool for Diagnosing COVID-19 Patients and Convalescents

Aim

COVID-19 triggers the overproduction of reactive oxygen species (ROS) which, in combination with a weakened antioxidant barrier, can lead to protein oxidation and lipid peroxidation. The aim of this study was to evaluate enzymatic and non-enzymatic antioxidants, the overall redox potential, and protein and lipid peroxidation products in COVID-19 patients, convalescents, and healthy subjects, and to the determine the diagnostic applicability of these parameters in COVID-19 patients.

Materials and Methods

The study involved 218 patients with COVID-19, 69 convalescents, and 48 healthy subjects who were selected for the research based on age and sex. The study was conducted between 20 February 2021 and 20 November 2021 in Białystok, Poland. The antioxidant barrier, redox status, and oxidative damage products were assessed in serum/plasma samples with the use of colorimetric and spectrophotometric assays.

Results

Glutathione reductase (GR) activity was higher, whereas total antioxidant capacity (TAC) was lower in COVID-19 patients than in convalescents (p<0.0001) and the control group (p<0.0001). The concentrations of advanced glycation end products (AGEs), advanced oxidation protein products (AOPP), 4-hydroxynonenal (4-HNE), and malondialdehyde (MDA) were higher in COVID-19 patients (p<0.0001) and convalescents (p<0.0001) than in the control group. AGEs were the most effective diagnostic biomarker for differentiating COVID-19 patients from the control group (AUC=0.9971) and convalescents from the control group (AUC=1.000).

Conclusion

An infection with the SARS-CoV-2 disrupts the redox balance and increases protein oxidation and lipid peroxidation. AGEs fulfill the criteria for a potential diagnostic biomarker in COVID-19 patients and convalescents.

Significance of nitrosative stress and glycoxidation products in the diagnosis of COVID-19

Nitrosative stress promotes protein glycoxidation, and both processes can occur during an infection with the SARS-CoV-2 virus. Therefore, the aim of this study was to assess selected nitrosative stress parameters and protein glycoxidation products in COVID-19 patients and convalescents relative to healthy subjects, including in reference to the severity of COVID-19 symptoms. The diagnostic utility of nitrosative stress and protein glycoxidation biomarkers was also evaluated in COVID-19 patients. The study involved 218 patients with COVID-19, 69 convalescents, and 48 healthy subjects. Nitrosative stress parameters (NO, S-nitrosothiols, nitrotyrosine) and protein glycoxidation products (tryptophan, kynurenine, N-formylkynurenine, dityrosine, AGEs) were measured in the blood plasma or serum with the use of colorimetric/fluorometric methods. The levels of NO (p = 0.0480), S-nitrosothiols (p = 0.0004), nitrotyrosine (p = 0.0175), kynurenine (p < 0.0001), N-formylkynurenine (p < 0.0001), dityrosine (p < 0.0001), and AGEs (p < 0.0001) were significantly higher, whereas tryptophan fluorescence was significantly (p < 0.0001) lower in COVID-19 patients than in the control group. Significant differences in the analyzed parameters were observed in different stages of COVID-19. In turn, the concentrations of kynurenine (p < 0.0001), N-formylkynurenine (p < 0.0001), dityrosine (p < 0.0001), and AGEs (p < 0.0001) were significantly higher, whereas tryptophan levels were significantly (p < 0.0001) lower in convalescents than in healthy controls. The ROC analysis revealed that protein glycoxidation products can be useful for diagnosing infections with the SARS-CoV-2 virus because they differentiate COVID-19 patients (KN: sensitivity-91.20%, specificity-92.00%; NFK: sensitivity-92.37%, specificity-92.00%; AGEs: sensitivity-99,02%, specificity-100%) and convalescents (KN: sensitivity-82.22%, specificity-84.00%; NFK: sensitivity-82,86%, specificity-86,00%; DT: sensitivity-100%, specificity-100%; AGE: sensitivity-100%, specificity-100%) from healthy subjects with high sensitivity and specificity. Nitrosative stress and protein glycoxidation are intensified both during and after an infection with the SARS-CoV-2 virus. The levels of redox biomarkers fluctuate in different stages of the disease. Circulating biomarkers of nitrosative stress/protein glycoxidation have potential diagnostic utility in both COVID-19 patients and convalescents.

The Effects of Six Weeks Pulmonary Rehabilitation on Functional and Psychological Outcomes in Long-COVID Patients: Preliminary Results from Serbian Single Center Study

Background and Objectives: In this study, we aimed to evaluate the effects of six weeks of pulmonary rehabilitation on functional and psychological outcomes in long-COVID patients. Material and Methods: The prospective clinical study included 46 patients that were diagnosed with COVID-19. A respiratory rehabilitation program was implemented for six weeks. Further valuables were tested before the beginning of the rehabilitation program (admission) and six weeks after (discharge): SpO2, heart rate, respiratory rate, Visual Analogue Scale (VAS) score, Borg score, Sit-to-Stand (StS) test number of repetition, distance of 6-Minute Walking Test (6MWT), Patient Health Questionnaire (PHQ) 9 score and Generalized anxiety disorder (GAD) anxiety score. These parameters were tested before the rehabilitation program on admission and at discharge and after the rehabilitation program on admission and at discharge. The results were presented with standard descriptive and analytical methods. Differences between the continuous variables before and after physical rehabilitation intervention were tested using the Wilcoxon test. Graphical analysis is presented with a box plot. Results: On discharge, in comparison with admission, the values of SpO2 were significantly lower (p = 0.007) before the 6MWT, and VAS scores were significantly higher (p = 0.036), while after the 6MWT, VAS scores were significantly lower (p < 0.001) as were Borg scores (p = 0.016). On discharge, in comparison with admission, the respiratory rate was significantly higher (p = 0.005) before the StS test, and Borg scores were significantly lower (p = 0.001), while after the StS test, SpO2 levels were significantly higher (p = 0.036) and VAS scores were significantly lower (p < 0.001), as were Borg scores (p = 0.008). After discharge, the values of the StS test were significantly higher (p = 0.011), PHQ9 scores were significantly lower (p < 0.001) and GAD anxiety scores were significantly lower as well (p = 0.005), while the distances measured in meters on the 6MWT were significantly increased (p < 0.001). Conclusions: A structured rehabilitation program in our study was shown to have beneficial effects on physiological, psychological and functional improvements in patients with long-COVID, and therefore it is advisable for these patients.

Factors Associated with Long COVID Recovery among US Adults

BACKGROUND

While factors associated with long COVID (LC) continue to be illuminated, little is known about recovery. This study used national survey data to assess factors associated with recovery from LC.

METHODS

We used data from the 2022 National Health Interview Survey, a cross-sectional sample of noninstitutionalized US adults. Survey analysis was used to account for oversampling and nonresponse bias and to obtain nationally representative estimates. A multivariable logistic regression model was used to identify potential predictors of LC recovery.

RESULTS

Among those reporting ever having COVID-19, 17.7% or an estimated 17.5 million American adults reported ever having LC, and among those with LC, 48.5% or an estimated 8.5 million reported having recovered. Multivariable logistic regression analysis showed that Hispanic adults were significantly more likely than White adults to report recovery from LC. At the same time, those with severe COVID-19 symptoms and those who had more than a high school degree, were aged 40 years or older, or were female were less likely to report recovery.

CONCLUSION

Significant variations in LC recovery were noted across age, sex, race and ethnicity, education, and severity of COVID-19 symptoms. Further work is needed to elucidate the causes of these differences and identify strategies to increase recovery rates.

Melatonin: a ferroptosis inhibitor with potential therapeutic efficacy for the post-COVID-19 trajectory of accelerated brain aging and neurodegeneration

The unprecedented pandemic of COVID-19 swept millions of lives in a short period, yet its menace continues among its survivors in the form of post-COVID syndrome. An exponentially growing number of COVID-19 survivors suffer from cognitive impairment, with compelling evidence of a trajectory of accelerated aging and neurodegeneration. The novel and enigmatic nature of this yet-to-unfold pathology demands extensive research seeking answers for both the molecular underpinnings and potential therapeutic targets. Ferroptosis, an iron-dependent cell death, is a strongly proposed underlying mechanism in post-COVID-19 aging and neurodegeneration discourse. COVID-19 incites neuroinflammation, iron dysregulation, reactive oxygen species (ROS) accumulation, antioxidant system repression, renin-angiotensin system (RAS) disruption, and clock gene alteration. These events pave the way for ferroptosis, which shows its signature in COVID-19, premature aging, and neurodegenerative disorders. In the search for a treatment, melatonin shines as a promising ferroptosis inhibitor with its repeatedly reported safety and tolerability. According to various studies, melatonin has proven efficacy in attenuating the severity of certain COVID-19 manifestations, validating its reputation as an anti-viral compound. Melatonin has well-documented anti-aging properties and combating neurodegenerative-related pathologies. Melatonin can block the leading events of ferroptosis since it is an efficient anti-inflammatory, iron chelator, antioxidant, angiotensin II antagonist, and clock gene regulator. Therefore, we propose ferroptosis as the culprit behind the post-COVID-19 trajectory of aging and neurodegeneration and melatonin, a well-fitting ferroptosis inhibitor, as a potential treatment.

Development of a Management App for Postviral Fibromyalgia-Like Symptoms: Patient Preference-Guided Approach

BACKGROUND

Persistent fibromyalgia-like symptoms have been increasingly reported following viral infections, including SARS-CoV-2. About 30% of patients with post-COVID-19 syndrome fulfill the fibromyalgia criteria. This complex condition presents significant challenges in terms of self-management. Digital health interventions offer a viable means to assist patients in managing their health conditions. However, the challenge of ensuring their widespread adoption and adherence persists. This study responds to this need by developing a patient-centered digital health management app, incorporating patient preferences to enhance usability and effectiveness, ultimately aiming to improve patient outcomes and quality of life.

OBJECTIVE

This research aims to develop a digital health self-management app specifically for patients experiencing postviral fibromyalgia-like symptoms. By prioritizing patient preferences and engagement through the app's design and functionality, the study intends to facilitate better self-management practices and improve adherence.

METHODS

Using an exploratory study design, the research used patient preference surveys and usability testing as primary tools to inform the development process of the digital health solution. We gathered and analyzed patients' expectations regarding design features, content, and usability to steer the iterative app development.

RESULTS

The study uncovered crucial insights from patient surveys and usability testing, which influenced the app's design and functionality. Key findings included a preference for a symptom list over an automated chatbot, a desire to report on a moderate range of symptoms and activities, and the importance of an intuitive onboarding process. While usability testing identified some challenges in the onboarding process, it also confirmed the importance of aligning the app with patient needs to enhance engagement and satisfaction.

CONCLUSIONS

Incorporating patient feedback has been a significant factor in the development of the digital health app. Challenges encountered with user onboarding during usability testing have highlighted the importance of this process for user adoption. The study acknowledges the role of patient input in developing digital health technologies and suggests further research to improve onboarding procedures, aiming to enhance patient engagement and their ability to manage digital health resources effectively.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

RR2-10.2196/32193.

Precision Phenotyping for Curating Research Cohorts of Patients with Post-Acute Sequelae of COVID-19 (PASC) as a Diagnosis of Exclusion

Scalable identification of patients with the post-acute sequelae of COVID-19 (PASC) is challenging due to a lack of reproducible precision phenotyping algorithms and the suboptimal accuracy, demographic biases, and underestimation of the PASC diagnosis code (ICD-10 U09.9). In a retrospective case-control study, we developed a precision phenotyping algorithm for identifying research cohorts of PASC patients, defined as a diagnosis of exclusion. We used longitudinal electronic health records (EHR) data from over 295 thousand patients from 14 hospitals and 20 community health centers in Massachusetts. The algorithm employs an attention mechanism to exclude sequelae that prior conditions can explain. We performed independent chart reviews to tune and validate our precision phenotyping algorithm. Our PASC phenotyping algorithm improves precision and prevalence estimation and reduces bias in identifying Long COVID patients compared to the U09.9 diagnosis code. Our algorithm identified a PASC research cohort of over 24 thousand patients (compared to about 6 thousand when using the U09.9 diagnosis code), with a 79.9 percent precision (compared to 77.8 percent from the U09.9 diagnosis code). Our estimated prevalence of PASC was 22.8 percent, which is close to the national estimates for the region. We also provide an in-depth analysis outlining the clinical attributes, encompassing identified lingering effects by organ, comorbidity profiles, and temporal differences in the risk of PASC. The PASC phenotyping method presented in this study boasts superior precision, accurately gauges the prevalence of PASC without underestimating it, and exhibits less bias in pinpointing Long COVID patients. The PASC cohort derived from our algorithm will serve as a springboard for delving into Long COVID's genetic, metabolomic, and clinical intricacies, surmounting the constraints of recent PASC cohort studies, which were hampered by their limited size and available outcome data.

Follow-up of cognitive impairment and inflammatory profile in individuals with mild COVID-19

Individuals who experience mild COVID-19 can suffer from long-lasting cognitive symptoms. Notably, 26% of these individuals experience difficulties with visuospatial abilities six months after infection. However, among those who initially exhibited visuoconstructive impairments, 66% showed improvement or complete reversal over time. Additionally, changes in cytokine levels, particularly CCL11, HGF, and CXCL10, were observed. These results suggest a potential link between ongoing cognitive issues and elevated levels of pro-inflammatory cytokines, which merits further investigation.

Biosound Therapy as a treatment for long COVID patients: A pre-post pilot study

BACKGROUND

43 % of people who are diagnosed with COVID-19 will experience persistent symptoms, also known as "long COVID," which lasts past the recovery of the acute infection. Long COVID symptoms overlap with symptoms that the Biosound Therapy System (BTS) has been shown to improve. The BTS is a multimodal treatment that includes biofeedback, vibroacoustic therapy synchronized with music that plays binaural beats, and video content. This study aimed to determine feasibility for a future full-scale Randomized Controlled Trial (RCT) and explore the impact of the BTS on long COVID symptoms.

METHODS

This pre-post pilot study was conducted in an outpatient mental health clinic. Adults aged 20-65 years old with persistent COVID-19 symptoms were screened and randomly assigned to the intervention or control group. The intervention group was given 8 Biosound Therapy sessions during a period of 4 weeks. All participants were assessed at baseline and at post-intervention using the Patient Health Questionnaire (PHQ-9), Generalized Anxiety Disorder 7-item scale (GAD-7), Cambridge Brain Sciences (CBS) tasks, and the COVID-19 Persistent Symptom Questionnaire. The feasibility outcomes were recruitment rates, retention rates, and open-ended questions about participants' experiences.

RESULTS

15 participants enrolled in the study and 13 completed the study (9 intervention, 4 control). Trial recruitment ended prematurely due to the emergence of the Omicron variant of COVID-19. Participants responded to open-ended questions with only positive remarks and made no comments on the study not being feasible. A Wilcoxon signed-rank test indicated that compared to baseline, participants in the intervention group had significant improvement in their GAD-7 score, PHQ9 score, 2 Cambridge Brain Science tasks ("Odd" and "Double Trouble"), fatigue, and difficulties in concentrating or remembering (p < 0.05; 95 % CI).

CONCLUSION

The intervention group showed promising improvement without reported side effects. A full-scale RCT is feasible as long as the recruitment setting is changed to a location that allows access to more patients with long COVID. Results were limited due to the small sample size; therefore, a full-scale trial is needed.

Proposal and Definition of an Intelligent Clinical Decision Support System Applied to the Prediction of Dyspnea after 12 Months of an Acute Episode of COVID-19

Long COVID is a condition that affects a significant proportion of patients who have had COVID-19. It is characterised by the persistence of associated symptoms after the acute phase of the illness has subsided. Although several studies have investigated the risk factors associated with long COVID, identifying which patients will experience long-term symptoms remains a complex task. Among the various symptoms, dyspnea is one of the most prominent due to its close association with the respiratory nature of COVID-19 and its disabling consequences. This work proposes a new intelligent clinical decision support system to predict dyspnea 12 months after a severe episode of COVID-19 based on the SeguiCovid database from the Álvaro Cunqueiro Hospital in Vigo (Galicia, Spain). The database is initially processed using a CART-type decision tree to identify the variables with the highest predictive power. Based on these variables, a cascade of expert systems has been defined with Mamdani-type fuzzy-inference engines. The rules for each system were generated using the Wang-Mendel automatic rule generation algorithm. At the output of the cascade, a risk indicator is obtained, which allows for the categorisation of patients into two groups: those with dyspnea and those without dyspnea at 12 months. This simplifies follow-up and the performance of studies aimed at those patients at risk. The system has produced satisfactory results in initial tests, supported by an AUC of 0.75, demonstrating the potential and usefulness of this tool in clinical practice.

Potential Anti-Inflammatory and Anti-Fatigue Effects of an Oral Food Supplement in Long COVID Patients

Long coronavirus disease (COVID) syndrome leads to chronic inflammatory state onset that can have a multisystem impact and compromise organ function. Moreover, long COVID syndrome is often characterized by the presence of chronic fatigue, which affects subjects' daily activities and worsens their quality of life. The aim of our double-blind, placebo-controlled randomized trial (protocol code RS 150.21, approved on 4 November 2021) was to evaluate the beneficial effects of the consumption of 2 cps/day, for two months, of an oral food supplement (OFS), based on Echinacea angustifolia, rosehip, propolis, royal jelly and zinc, in long COVID patients, compared to a two-month placebo period. The OFS's vitamin C content was equal to 22.17 mg/g (8.87 mg/capsule). The OFS's total polyphenol content was 43.98 mg/g gallic acid equivalents. At the end of the in vivo study, we highlighted a significant decrease in the inflammatory parameters in the OFS period, compared to the placebo period (neutrophil-to-lymphocyte ratio, p = 0.0455; monocyte to-lymphocyte ratio, p = 0.0005; C-reactive protein, p = 0.0145). Our study also highlighted a significant increase in vitamin D serum values (p = 0.0005) and, at the same time, an improvement in patients' life quality and a reduction in fatigue, monitored by the fatigue severity scale. This study showed the OFS's beneficial effects on the inflammatory state, fatigue and quality of life in long COVID patients.

Machine learning algorithms for detection of visuomotor neural control differences in individuals with PASC and ME

The COVID-19 pandemic has affected millions worldwide, giving rise to long-term symptoms known as post-acute sequelae of SARS-CoV-2 (PASC) infection, colloquially referred to as long COVID. With an increasing number of people experiencing these symptoms, early intervention is crucial. In this study, we introduce a novel method to detect the likelihood of PASC or Myalgic Encephalomyelitis (ME) using a wearable four-channel headband that collects Electroencephalogram (EEG) data. The raw EEG signals are processed using Continuous Wavelet Transform (CWT) to form a spectrogram-like matrix, which serves as input for various machine learning and deep learning models. We employ models such as CONVLSTM (Convolutional Long Short-Term Memory), CNN-LSTM, and Bi-LSTM (Bidirectional Long short-term memory). Additionally, we test the dataset on traditional machine learning models for comparative analysis. Our results show that the best-performing model, CNN-LSTM, achieved an accuracy of 83%. In addition to the original spectrogram data, we generated synthetic spectrograms using Wasserstein Generative Adversarial Networks (WGANs) to augment our dataset. These synthetic spectrograms contributed to the training phase, addressing challenges such as limited data volume and patient privacy. Impressively, the model trained on synthetic data achieved an average accuracy of 93%, significantly outperforming the original model. These results demonstrate the feasibility and effectiveness of our proposed method in detecting the effects of PASC and ME, paving the way for early identification and management of the condition. The proposed approach holds significant potential for various practical applications, particularly in the clinical domain. It can be utilized for evaluating the current condition of individuals with PASC or ME, and monitoring the recovery process of those with PASC, or the efficacy of any interventions in the PASC and ME populations. By implementing this technique, healthcare professionals can facilitate more effective management of chronic PASC or ME effects, ensuring timely intervention and improving the quality of life for those experiencing these conditions.

Reinforcing the Evidence of Mitochondrial Dysfunction in Long COVID Patients Using a Multiplatform Mass Spectrometry-Based Metabolomics Approach

Despite the recent and increasing knowledge surrounding COVID-19 infection, the underlying mechanisms of the persistence of symptoms for a long time after the acute infection are still not completely understood. Here, a multiplatform mass spectrometry-based approach was used for metabolomic and lipidomic profiling of human plasma samples from Long COVID patients (n = 40) to reveal mitochondrial dysfunction when compared with individuals fully recovered from acute mild COVID-19 (n = 40). Untargeted metabolomic analysis using CE-ESI(+/-)-TOF-MS and GC-Q-MS was performed. Additionally, a lipidomic analysis using LC-ESI(+/-)-QTOF-MS based on an in-house library revealed 447 lipid species identified with a high confidence annotation level. The integration of complementary analytical platforms has allowed a comprehensive metabolic and lipidomic characterization of plasma alterations in Long COVID disease that found 46 relevant metabolites which allowed to discriminate between Long COVID and fully recovered patients. We report specific metabolites altered in Long COVID, mainly related to a decrease in the amino acid metabolism and ceramide plasma levels and an increase in the tricarboxylic acid (TCA) cycle, reinforcing the evidence of an impaired mitochondrial function. The most relevant alterations shown in this study will help to better understand the insights of Long COVID syndrome by providing a deeper knowledge of the metabolomic basis of the pathology.

Exploring the Heart Failure Connection in Long COVID Patients: A Narrative Review

In this narrative review, we explore the relationship between long COVID patients and their risk of developing heart failure (HF). Patients with long COVID face a heightened risk of HF, a critical cardiovascular complication linked to the prolonged effects of COVID-19. Clinical manifestations of long COVID-associated HF present diagnostic challenges, complicating patient management. Multidisciplinary care is essential to address these complexities effectively. We found that long COVID can result in various cardiovascular issues including HF. The current view is long COVID leads to HF by activating systemic inflammation by causing endothelial dysfunction, which leads to activation of the complement pathways, tissue factor pathways, and Von Willebrand factor; activation of all these factors leads to venous and arterial thrombosis, which could lead to clogging of blood vessel of the heart leading to cardiovascular complications. The association between long COVID and HF can be challenging despite being recognized as comorbidity because biomarkers are not dependable in determining whether a patient had HF before or after contracting COVID-19. Emerging therapeutic modalities offer hope for improving outcomes, but further research is needed to refine management strategies and mitigate long-term cardiovascular consequences of COVID-19.

Incidence of long COVID and associated psychosocial characteristics in a large U.S. city

PURPOSE

Persistent residual effects from Coronavirus Disease-2019 (COVID-19) have been observed with varying definitions of "Long COVID" and little comprehensive examination. This study examined the incidence and psychosocial correlates of Long COVID using different definitions.

METHODS

Data were analyzed from a citywide sample of 3595 adults with lab-confirmed cases of COVID-19 that were surveyed over 3 months. Rates of Long COVID were examined in terms of Post-Acute COVID (PAC), defined as at least one symptom lasting for 4 weeks, and three levels of Post-COVID Syndrome (PCS) that included experiencing at least one symptom for 3 months (PCS-1), experiencing three or more symptoms for 3 months (PCS-2), or experiencing at least one of the same symptoms for 3 months (PCS-3).

RESULTS

Among the 686 participants who completed baseline, 1-month, and 3-month follow-up assessments, 75.7% had PAC, 55.0% had PSC-1, 26.5% had PSC-2, and 19.0% had PSC-3. Comparing participants with PAC and PSC-3 in the total sample with inverse probability weighting, multivariable analyses revealed being female, Asian or Native American, greater reported longlines, and less social support were predictive of PCS-3.

CONCLUSION

Residual effects of COVID-19 are very common and nearly one-fifth of our sample met the most restrictive definition of Long COVID warranting concern as a public health issue. Some demographic and social factors may predispose some adults to Long COVID, which should be considered for prevention and population health.

Prevalence of Vocal Fatigue Due to the Use of Facial Protective Gear in Teaching Medical Professionals

Since the COVID-19 pandemic, masks have become far more widely used by doctors and are now commonplace in the hospital, with many professionals still wearing them for extended amounts of time. Emerging literature describing numerous mask-related difficulties prompted the authors to conduct a study aimed at assessing the self-perceived impact on voices of teaching doctors due to facial protective gear. In this study carried out from October 2021 to March 2022, data was gathered from 170 pre-, para-, and clinical professionals who were involved in offline teaching. Over half of teaching medical professionals were found to be vocally fatigued. Pre and para-clinical professionals have greater vocal tiredness and avoidance than clinical doctors (p = 0.016). The type of mask used does not make a significant difference in degree of vocal fatigue. Individuals with lingering respiratory difficulties following COVID-19 were significantly more vocally fatigued than their recovered peers (p value for tiredness and avoidance = 0.010). Thus, teaching doctors are at risk of impaired quality of life due to vocal fatigue. Further research on vocal habits and rest practices in the study population may help identify the most effective interventions.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12070-023-04350-8.

Long COVID Among Kidney Transplant Recipients Appears to Be Attenuated During the Omicron Predominance

BACKGROUND

Omicron variant has been associated with milder cases of COVID-19 among kidney transplant recipients. However, little is known about postacute sequelae, referred to as Long COVID.

METHODS

Prospective, single-center cohort study investigating prevalence and risk factors for Long COVID among kidney transplant recipients during the omicron predominance in Brazil. The analysis included adult patients with confirmed SARS-CoV-2 infection between January 5, 2022, and July 18, 2022, were alive, had a functioning kidney transplant 3 mo after symptom onset, and answered a telephonic survey about physical complains of Long COVID.

RESULTS

From the 1529 eligible, 602 (39%) patients responded the survey. Sixteen percent reported a previous SARS-CoV-2 infection, and 85% had been fully vaccinated. The prevalence of Long COVID was 52%, with the most common complaints being weakness (46%), myalgia (41%), dizziness (33%), and headache (31%). Among employed patients, 94% were able to resume their normal work activities. In multivariable analysis, female gender (hazard ratio [HR], 2.14; 95% confidence interval [CI], 1.51-3.02; P  < 0.0001), previous SARS-CoV-2 infection (HR, 3.55; 95% CI, 1.91-6.60; P  < 0.0001), fatigue (HR, 2.32; 95% CI, 1.18-4.55; P  = 0.014), myalgia (HR, 1.48; 95% CI, 1.03-2.15; P  = 0.036) during the acute phase, and hospitalization because of COVID-19 (HR, 1.71; 95% CI, 1.06-2.76; P  = 0.028) were independently associated with Long COVID.

CONCLUSIONS

In the "omicron era," Long COVID among kidney transplant recipients exhibited milder characteristics and had a less significant impact on their ability to resume normal life activities. The risk factors for persistent symptoms were similar to those observed in the general population except for the vaccination status, underscoring the importance of closer monitoring in special subgroups.

Distinct subsets of anti-pulmonary autoantibodies correlate with disease severity and survival in severe COVID-19 patients

Autoantibodies targeting the lung tissue were identified in severe COVID-19 patients in this retrospective study. Fifty-three percent of 104 patients developed anti-pulmonary antibodies, the majority of which were IgM class, suggesting that they developed upon infection with SARS-CoV-2. Anti-pulmonary antibodies correlated with worse pulmonary function and a higher risk of multiorgan failure that was further aggravated if 3 or more autoantibody clones were simultaneously present (multi-producers). Multi-producer patients were older than the patients with less or no autoantibodies. One of the identified autoantibodies (targeting a pulmonary protein of ~ 50 kDa) associated with worse clinical outcomes, including mortality. In summary, severe COVID-19 is associated with the development of lung-specific autoantibodies, which may worsen the clinical outcome. Tissue proteome-wide tests, such as the ones applied here, can be used to detect autoimmunity in the post-COVID state to identify the cause of symptoms and to reveal a new target for treatment.

Patient experiences of the Long COVID-Optimal Health Programme: a qualitative interview study in community settings

BACKGROUND

Long COVID (LC) symptoms persist 12 weeks or more beyond the acute infection. To date, no standardised diagnostic or treatment pathways exist. However, a holistic approach has been recommended. This study explored participants' experiences of a Long COVID-Optimal Health Programme (LC-OHP); a psychoeducational self-efficacy programme.

AIM

To explore perceptions and experiences of people with LC regarding the LC-OHP and identify suggestions to further improve the programme.

DESIGN & SETTING

Qualitative study with patients with LC recruited through community settings.

METHOD

This study is part of a wider randomised controlled trial. Eligible participants were aged ≥18 years, have LC, and attended a minimum of five LC-OHP sessions plus a booster session. We interviewed those randomised to the intervention group. Interviews were conducted by an independent researcher and thematically analysed to identify common, emerging themes.

RESULTS

Eleven participants were interviewed, mostly women from a White British ethnic group (n = 10). Four main themes were identified, reflecting programme benefits and suggestions for improvement. The programme demonstrated potential for assisting patients in managing their LC, including physical health and mental wellbeing. Participants found the programme to be flexible and provided suggestions to adapting it for future users.

CONCLUSION

Findings support the acceptability of the LC-OHP to people living with LC. The programme has shown several benefits in supporting physical health and mental wellbeing. Suggestions made to further adapt the programme and improve its delivery will be considered for future trials.

An open trial of biofeedback for long COVID

OBJECTIVE

Biofeedback is a therapeutic treatment model that teaches self-regulation of autonomic functions to alleviate stress-related symptoms. "Long COVID" refers to chronic physical and cognitive sequelae post-SARS-CoV-2 infection. This study examined the efficacy of a six-week intervention, consisting of weekly one-hour sessions combining heart rate variability and temperature biofeedback, for alleviating mood symptoms, somatic symptoms and sleep disturbance of patients diagnosed with long COVID.

METHODS

Data were collected from 20 adult participants aged 22-63 (Mage = 44.1, SDage = 12.2) with varying long COVID symptoms. Within this single arm design, 16 of the 20 participants completed all six sessions of biofeedback; 14 completed an assessment at the three-month post-treatment time point.

RESULTS

Participants self-reported significant improvements in somatic, anxiety, and depressive symptoms, sleep quality, quality of life, and number of "bad days" immediately after the intervention and three months later (Cohen's d effect size (ES) = 1.09-0.46). Reduced number of medical doctor visits (ES = 0.85) and prescription drug use over the last month (odds ratio = 0.33), as well as improved emotional wellbeing (ES = 0.97) were observed at the three-month time point only.

CONCLUSION

Results suggest that this short, readily scalable intervention can be potentially efficacious in alleviating symptoms of long COVID. Despite notable improvements, the major limitation of this study is its lack of control group. While a randomized trial merits study, biofeedback appears to be a brief, effective, non-invasive, and low-cost treatment option for patients with chronic somatic symptoms secondary to SARS-CoV-2 infection.

CLINICALTRIALS

govID: NCT05120648.

Social determinants of health predict readmission following COVID-19 hospitalization: a health information exchange-based retrospective cohort study

Introduction

Since February 2020, over 104 million people in the United States have been diagnosed with SARS-CoV-2 infection, or COVID-19, with over 8.5 million reported in the state of Texas. This study analyzed social determinants of health as predictors for readmission among COVID-19 patients in Southeast Texas, United States.

Methods

A retrospective cohort study was conducted investigating demographic and clinical risk factors for 30, 60, and 90-day readmission outcomes among adult patients with a COVID-19-associated inpatient hospitalization encounter within a regional health information exchange between February 1, 2020, to December 1, 2022.

Results and discussion

In this cohort of 91,007 adult patients with a COVID-19-associated hospitalization, over 21% were readmitted to the hospital within 90  days (n = 19,679), and 13% were readmitted within 30  days (n = 11,912). In logistic regression analyses, Hispanic and non-Hispanic Asian patients were less likely to be readmitted within 90  days (adjusted odds ratio [aOR]: 0.8, 95% confidence interval [CI]: 0.7-0.9, and aOR: 0.8, 95% CI: 0.8-0.8), while non-Hispanic Black patients were more likely to be readmitted (aOR: 1.1, 95% CI: 1.0-1.1, p = 0.002), compared to non-Hispanic White patients. Area deprivation index displayed a clear dose-response relationship to readmission: patients living in the most disadvantaged neighborhoods were more likely to be readmitted within 30 (aOR: 1.1, 95% CI: 1.0-1.2), 60 (aOR: 1.1, 95% CI: 1.2-1.2), and 90  days (aOR: 1.2, 95% CI: 1.1-1.2), compared to patients from the least disadvantaged neighborhoods. Our findings demonstrate the lasting impact of COVID-19, especially among members of marginalized communities, and the increasing burden of COVID-19 morbidity on the healthcare system.

The Effects of an Eight-Week Swimming Program on Body Composition and Assessment of Dietary Intake in Post-COVID-19 Patients

COVID-19 infection and its consequences (long-term COVID-19 syndrome) have implications for weight loss, body composition, and diet quality. In the context of the "PostCovSwim" project, which is part of a broader international study, the impact of an eight-week swimming program on post-COVID-19 patients' nutritional status (i.e., body composition and dietary intake) was evaluated. Body composition and dietary intake were assessed by medically approved and calibrated bioelectrical impedance (Tanita 780 S MA) and food frequency questionnaires. At the baseline, most participants were classified as overweight based on their body mass index (BMI). However, their body fat percentage (BF%) classification indicated normal weight, although females were near obesity thresholds. Furthermore, at the baseline, according to the BMI classification, 62% of females and 61% of males were female, whereas according to the BF% for obesity classification, 44% of females and 43% of males were considered overweight or obese. Surprisingly, despite the eight-week program, there were no significant changes in body composition. Additionally, the assessment of dietary intake, which remained consistent throughout the study, revealed dietary imbalances characterized by an unhealthy low-carbohydrate, high-fat dietary pattern. This dietary pattern entailed excessive consumption of ultraprocessed foods; reduced carbohydrate intake (39% E vs. 37% E); increased total fat intake (46% E vs. 47% E); increased saturated fatty acids (14% E vs. 13% E); increased cholesterol (412 mg/d vs. 425 mg/d); increased free sugars (7% E vs. 7% E); and inadequate intake of fibre (24 g/d vs. 20 g/d), polyunsaturated fatty acids (6.6% E vs. 7.7% E), vitamin B12 (in females: 3.1 µg/d), vitamin C (86 mg/d vs. 66 mg/d), vitamin D (2 µg/d vs. 3.2 µg/d), folate (in males: 258 µg/d), calcium (777 mg/d vs. 743 mg/d), and selenium (in males: 66 µg/d). After an eight-week swimming program following COVID-19, no significant changes were observed in the subjects' body composition. Their dietary intake was found to not align with the dietary recommendations. These findings underscore the urgency of implementing comprehensive dietary and lifestyle interventions for post-COVID-19 patients to optimize their recovery and overall well-being. Physical activity, like a swimming program, may positively affect various aspects of human well-being.

Microbiological profile of long COVID and associated clinical and radiological findings: a prospective cross-sectional study

OBJECTIVE

To study the frequency of microbiological etiology of respiratory infections in patients with long COVID and their associated clinical and radiological findings.

METHODS

Nasopharyngeal swabs and sputum specimens were collected from 97 patients with respiratory illness stemming from long COVID. The specimens were assessed for their microbiological profile (bacteria and virus) and their association with the overall clinical and radiological picture.

RESULTS

In total, 23 (24%) patients with long COVID had viral infection (n = 12), bacterial infection (n = 9), or coinfection (n = 2). Microorganisms were detected at significantly higher rates in hospitalized patients, patients with moderate COVID-19, and patients with asthma (P < .05). Tachycardia (65%) was the most common symptom at presentation. A statistically significant number of patients with long COVID who had viral infection presented with cough and myalgia; and a statistically significant number of patients with long COVID who had bacterial infection presented with productive coughing (P < .05). Post-COVID fibrotic changes were found in 61% of cohort patients (31/51).

CONCLUSION

A decreasing trend of respiratory pathogens (enveloped viruses and bacteria) was found in long COVID. An analysis including a larger group of viral- or bacterial-infected patients with long COVID is needed to obtain high-level evidence on the presenting symptoms (cough, myalgia) and their association with the underlying comorbidities and severity.

Small Molecules for the Treatment of Long-COVID-Related Vascular Damage and Abnormal Blood Clotting: A Patent-Based Appraisal

People affected by COVID-19 are exposed to, among others, abnormal clotting and endothelial dysfunction, which may result in deep vein thrombosis, cerebrovascular disorders, and ischemic and non-ischemic heart diseases, to mention a few. Treatments for COVID-19 include antiplatelet (e.g., aspirin, clopidogrel) and anticoagulant agents, but their impact on morbidity and mortality has not been proven. In addition, due to viremia-associated interconnected prothrombotic and proinflammatory events, anti-inflammatory drugs have also been investigated for their ability to mitigate against immune dysregulation due to the cytokine storm. By retrieving patent literature published in the last two years, small molecules patented for long-COVID-related blood clotting and hematological complications are herein examined, along with supporting evidence from preclinical and clinical studies. An overview of the main features and therapeutic potentials of small molecules is provided for the thromboxane receptor antagonist ramatroban, the pan-caspase inhibitor emricasan, and the sodium-hydrogen antiporter 1 (NHE-1) inhibitor rimeporide, as well as natural polyphenolic compounds.

Before and after COVID-19: Changes in symptoms and diagnoses in 13,033 adults

BACKGROUND

Most patients with COVID-19 report experiencing one or more symptoms after acute infection subsides, known as post-acute sequelae of SARS-CoV-2 infection (PASC). Though research has examined PASC after acute COVID-19, few studies have examined PASC over a longer follow-up duration or accounted for rates of symptoms and diagnoses before COVID-19 infection, and included those not actively seeking treatment for PASC. To determine what symptoms and diagnoses are occurring at higher rates after acute COVID-19 infection from a more inclusive sample, we extracted electronic hospital records (EHR) data from 13,033 adults with previously known diagnoses and symptoms.

METHODS

The sample was comprised of patients who had a positive PCR test for SARS-CoV-2 between March 1, 2020, and December 31, 2020, and follow-up was conducted through November 29, 2021. All patients in the sample had medical appointments ≥4 weeks before and ≥4 weeks after their positive PCR test. At these appointments, all ICD-10 codes recorded in the EHR were classified into 21 categories based on the literature and expert review. Conditional logistic regression models were used to quantify the odds of these symptoms and diagnostic categories following COVID-19 infection relative to visits occurring before infection. The sample was comprised of 28.0% adults over 65 and was 57.0% female. After the positive PCR test, the most recorded diagnoses and symptoms were dyspnea and respiratory failure, myositis, musculoskeletal pain/stiffness, anxiety, and depression.

RESULTS

Results from regression analyses showed increased odds of diagnosis for 15 of the 21 categories following positive PCR. Relative to pre-COVID, the diagnoses and symptoms with the greatest odds after a positive PCR test were loss of smell or taste [OR (95% CI) = 6.20 (3.18-12.09)], pulmonary fibrosis [3.50 (1.59-7.68)], and dyspnea/respiratory failure [2.14 (1.92-2.40)]. Stratification of these analyses by age, gender, race, and ethnicity showed similar results.

CONCLUSION

The increased symptoms and diagnoses detected in the current study match prior analyses of PASC diagnosis and treatment-seeking patients. The current research expands upon the literature by showing that these symptoms are more frequently detected following acute COVID-19 than before COVID-19. Further, our analyses provide a broad snapshot of the population as we were able to describe PASC among all patients who tested positive for COVID-19.

The knowns and unknowns of long COVID-19: from mechanisms to therapeutical approaches

The coronavirus disease 2019 (COVID-19) pandemic caused by SARS-CoV-2 has been defined as the greatest global health and socioeconomic crisis of modern times. While most people recover after being infected with the virus, a significant proportion of them continue to experience health issues weeks, months and even years after acute infection with SARS-CoV-2. This persistence of clinical symptoms in infected individuals for at least three months after the onset of the disease or the emergence of new symptoms lasting more than two months, without any other explanation and alternative diagnosis have been named long COVID, long-haul COVID, post-COVID-19 conditions, chronic COVID, or post-acute sequelae of SARS-CoV-2 (PASC). Long COVID has been characterized as a constellation of symptoms and disorders that vary widely in their manifestations. Further, the mechanisms underlying long COVID are not fully understood, which hamper efficient treatment options. This review describes predictors and the most common symptoms related to long COVID's effects on the central and peripheral nervous system and other organs and tissues. Furthermore, the transcriptional markers, molecular signaling pathways and risk factors for long COVID, such as sex, age, pre-existing condition, hospitalization during acute phase of COVID-19, vaccination, and lifestyle are presented. Finally, recommendations for patient rehabilitation and disease management, as well as alternative therapeutical approaches to long COVID sequelae are discussed. Understanding the complexity of this disease, its symptoms across multiple organ systems and overlapping pathologies and its possible mechanisms are paramount in developing diagnostic tools and treatments.

Echocardiographic findings in non-hospitalised children and adolescents following acute COVID-19

BACKGROUND

Although COVID-19 is known to have cardiac effects in children, seen primarily in severe disease, more information is needed about the cardiac effects following COVID-19 in non-hospitalised children and adolescents during recovery. This study aims to compare echocardiographic markers of cardiac size and function of children following acute COVID-19 with those of healthy controls.

METHODS

This single-centre retrospective case-control study compared 71 cases seen in cardiology clinic following acute COVID-19 with 33 healthy controls. Apical left ventricle, apical right ventricle, and parasternal short axis at the level of the papillary muscles were analysed to measure ventricular size and systolic function. Strain was analysed on vendor-independent software. Statistical analysis was performed using t-test, chi-square, Wilcoxon rank sum, and regression modelling as appropriate (p < 0.05 significant).

RESULTS

Compared to controls, COVID-19 cases had slightly higher left ventricular volumes and lower left ventricular ejection fraction and right ventricular fractional area change that remained within normal range. There were no differences in right or left ventricular longitudinal strain between the two groups. Neither initial severity nor persistence of symptoms after diagnosis predicted these differences.

CONCLUSIONS

Echocardiographic findings in children and adolescents 6 weeks to 3 months following acute COVID-19 not requiring hospitalisation were overall reassuring. Compared to healthy controls, the COVID-19 group demonstrated mildly larger left ventricular size and lower conventional measures of biventricular systolic function that remained within the normal range, with no differences in biventricular longitudinal strain. Future studies focusing on longitudinal echocardiographic assessment of patients following acute COVID-19 are needed to better understand these subtle differences in ventricular size and function.

Role of the SARS-CoV-2 Virus in Brain Cells

COVID-19, caused by the SARS-CoV-2 virus, can have neurological effects, including cognitive symptoms like brain fog and memory problems. Research on the neurological effects of COVID-19 is ongoing, and factors such as inflammation, disrupted blood flow, and damage to blood vessels may contribute to cognitive symptoms. Notably, some authors and existing evidence suggest that the SARS-CoV-2 virus can enter the central nervous system through different routes, including the olfactory nerve and the bloodstream. COVID-19 infection has been associated with neurological symptoms such as altered consciousness, headaches, dizziness, and mental disorders. The exact mechanisms and impact on memory formation and brain shrinkage are still being studied. This review will focus on pathways such as the olfactory nerve and blood-brain barrier disruption, and it will then highlight the interactions of the virus with different cell types in the brain, namely neurons, astrocytes, oligodendrocytes, and microglia.

Evaluation of Pulmonary Function Tests, Dyspnea Scores, and Antibody Levels at the Six-Month Follow-Up of Patients Hospitalized for COVID-19 Pneumonia

BACKGROUND

Coronavirus disease 2019 (COVID-19) causes various signs and symptoms, especially lung involvement, during acute infection and in the long term. In this study, we evaluated the follow-up results of patients with chronic COVID-19 over a 24-week period.

METHODS

The study included a total of 100 post-COVID-19 patients (confirmed by real-time polymerase chain reaction (PCR) of a nasopharyngeal swab) who presented to the post-COVID-19 outpatient clinic with chronic COVID-19 symptoms 12 weeks after diagnosis, between April and June 2021. All of the patients in the study had a history of hospitalization and were grouped based on the severity of the acute COVID-19 infection (moderate: group 1, severe: group 2).

RESULTS

A comparison of pulmonary function test parameters at week 12 showed that forced expiratory volume (FEV1)%, forced vital capacity (FVC)%, diffusing capacity of the lungs for carbon monoxide (DLCO)%, and DLCO divided by the alveolar volume (DLCO/VA)% values were significantly lower in group 2 than in group 1 (p<0.001 for all). At week 24, only DLCO and DLCO/VA values were lower (<0.001 for both). The mean modified Medical Research Council (mMRC) dyspnea scores of groups 1 and 2 were 1.4 ± 0.9 and 2.8 ± 1.1 at 12 weeks and improved to 0.9 ± 0.6 and 1.6 ± 0.6 at 24 weeks, respectively. The groups' mMRC scores at 12 and 24 weeks differed significantly (p=0.001, p=0.02). There was no difference in levels of IgM and IgG antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein between the groups at 12 or 24 weeks (p>0.05 for all).

CONCLUSION

Improvement in pulmonary function parameters and mMRC scores may take longer than 24 weeks, especially in patients with severe COVID-19. Our results indicated that the levels of IgM and IgG neutralizing antibodies did not differ between patients with moderate and severe illness at 12 or 24 weeks.

IFN-γ decreases PD-1 in T lymphocytes from convalescent COVID-19 patients via the AKT/GSK3β signaling pathway

Post-COVID-19 syndrome may be associated with the abnormal immune status. Compared with the unexposed age-matched elder group, PD-1 in the CD8+ T cells from recovered COVID-19 patients was significantly lower. IFN-γ in the plasma of COVID-19 convalescent patients was increased, which inhibited PD-1 expression in CD8+ T cells from COVID-19 convalescent patients. scRNA-seq bioinformatics analysis revealed that AKT/GSK3β may regulate the INF-γ/PD-1 axis in CD8+ T cells from COVID-19 convalescent patients. In parallel, an IFN-γ neutralizing antibody reduced AKT and increased GSK3β in PBMCs. An AKT agonist (SC79) significantly decreased p-GSK3β. Moreover, AKT decreased PD-1 on CD8+ T cells, and GSK3β increased PD-1 on CD8+ T cells according to flow cytometry analysis. Collectively, we demonstrated that recovered COVID-19 patients may develop long COVID. Increased IFN-γ in the plasma of recovered Wuhan COVID-19 patients contributed to PD-1 downregulation on CD8+ T cells by regulating the AKT/GSK3β signaling pathway.

Pathophysiological, immunological, and inflammatory features of long COVID

The COVID-19 pandemic continues to cause severe global disruption, resulting in significant excess mortality, overwhelming healthcare systems, and imposing substantial social and economic burdens on nations. While most of the attention and therapeutic efforts have concentrated on the acute phase of the disease, a notable proportion of survivors experience persistent symptoms post-infection clearance. This diverse set of symptoms, loosely categorized as long COVID, presents a potential additional public health crisis. It is estimated that 1 in 5 COVID-19 survivors exhibit clinical manifestations consistent with long COVID. Despite this prevalence, the mechanisms and pathophysiology of long COVID remain poorly understood. Alarmingly, evidence suggests that a significant proportion of cases within this clinical condition develop debilitating or disabling symptoms. Hence, urgent priority should be given to further studies on this condition to equip global public health systems for its management. This review provides an overview of available information on this emerging clinical condition, focusing on the affected individuals' epidemiology, pathophysiological mechanisms, and immunological and inflammatory profiles.