Characterising long COVID: a living systematic review

Long-term effects of SARS-CoV-2 infection on human brain and memory

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants have caused several waves of outbreaks. From the ancestral strain to Omicron variant, SARS-CoV-2 has evolved with the high transmissibility and increased immune escape against vaccines. Because of the multiple basic amino acids in the S1-S2 junction of spike protein, the widespread distribution of angiotensin-converting enzyme 2 (ACE2) receptor in human body and the high transmissibility, SARS-CoV-2 can infect multiple organs and has led to over 0.7 billion infectious cases. Studies showed that SARS-CoV-2 infection can cause more than 10% patients with the Long-COVID syndrome, including pathological changes in brains. This review mainly provides the molecular foundations for understanding the mechanism of SARS-CoV-2 invading human brain and the molecular basis of SARS-CoV-2 infection interfering with human brain and memory, which are associated with the immune dysfunction, syncytia-induced cell death, the persistence of SARS-CoV-2 infection, microclots and biopsychosocial aspects. We also discuss the strategies for reducing the Long-COVID syndrome. Further studies and analysis of shared researches will allow for further clarity regarding the long-term health consequences.

Multidisciplinary inpatient rehabilitation for older adults with COVID-19: a systematic review and meta-analysis of clinical and process outcomes

BACKGROUND

Older adults are at increased risk for disease severity and poorer prognosis following COVID-19 infection. The aim of this systematic review and meta-analysis is to explore the impact of multidisciplinary rehabilitation in the acute or post-acute hospital setting for older adults with COVID-19.

METHODS

The Cochrane library, EMBASE, Cinahl and Medline (via EBSCO), PubMed, and Web of Science were systematically searched in June 2022 and a repeat search was completed in March 2023. Screening, data extraction and quality appraisal were conducted independently by two reviewers. Studies reporting outcomes for older adults following multidisciplinary rehabilitation (provided by two or more Health and Social Care Professionals) were included. Both observational and experimental study designs were included. The primary outcome was functional ability. Secondary outcomes included discharge disposition, acute hospital and rehabilitation unit length of stay, mortality, primary and secondary healthcare utilisation, and long-term effects of COVID-19.

RESULTS

Twelve studies met the inclusion criteria, comprising a total of 570 older adults. Where reported, older adults stayed in the acute hospital for a mean of 18 days (95%CI, 13.35- 23.13 days) and in rehabilitation units for 19 days (95%CI, 15.88-21.79 days). There was a significant improvement in functional ability among older adults with COVID-19 who received multidisciplinary rehabilitation (REM, SMD = 1.46, 95% CI 0.94 to 1.98). The proportion of older adults who were discharged directly home following rehabilitation ranged from 62 to 97%. Two studies reported a 2% inpatient mortality rate of older persons during rehabilitative care. No study followed up patients after the point of discharge and no study reported on long term effects of COVID-19.

CONCLUSIONS

Multidisciplinary rehabilitation may result in improved functional outcomes on discharge from rehabilitation units/centres for older adults with COVID-19. Findings also highlight the need for further research into the long-term effect of rehabilitation for older adults following COVID-19. Future research should comprehensively describe multidisciplinary rehabilitation in terms of disciplines involved and the intervention provided.

Post-COVID symptom profiles and duration in a global convalescent COVID-19 observational cohort: Correlations with demographics, medical history, acute COVID-19 severity and global region

Background

Post-COVID conditions are characterised by persistent symptoms that negatively impact quality of life after SARS-CoV-2 diagnosis. While post-COVID risk factors and symptoms have been extensively described in localised regions, especially in the global north, post-COVID conditions remain poorly understood globally. The global, observational cohort study HVTN 405/HPTN 1901 characterises the convalescent course of SARS-CoV-2 infection among adults in North and South America and Africa.

Methods

We categorised the cohort by infection severity (asymptomatic, symptomatic, no oxygen requirement (NOR), non-invasive oxygen requirement (NIOR), invasive oxygen requirement (IOR)). We applied a regression model to assess correlations of demographics, co-morbidities, disease severity, and concomitant medications with COVID-19 symptom persistence and duration across global regions.

Results

We enrolled 759 participants from Botswana, Malawi, South Africa, Zambia, Zimbabwe, Peru, and the USA a median of 51 (interquartile range (IQR) = 35-66) days post-diagnosis, from May 2020 to March 2021. 53.8% were female, 69.8% were 18-55 years old (median (md) = 44 years old, IQR = 33-58). Comorbidities included obesity (42.8%), hypertension (24%), diabetes (14%), human immunodeficiency virus (HIV) infection (11.6%) and lung disease (7.5%). 76.2% were symptomatic (NOR = 47.4%; NIOR = 22.9%; IOR = 5.8%). Median COVID-19 duration among symptomatic participants was 20 days (IQR = 11-35); 43.4% reported symptoms after COVID-19 resolution, 33.6% reported symptoms ≥30 days, 9.9% reported symptoms ≥60 days. Symptom duration correlated with disease severity (P < 0.001, NIOR vs NOR; P = 0.003, IOR vs NOR), lung disease (P = 0.001), race (P < 0.05, non-Hispanic Black vs White), and global region (P < 0.001). Prolonged viral shedding correlated with persistent abdominal pain (odds ratio (OR) = 5.51, P < 0.05) and persistent diarrhoea (OR = 6.64, P < 0.01).

Conclusions

Post-COVID duration varied with infection severity, race, lung disease, and region. Better understanding post-COVID conditions, including regionally-diverse symptom profiles, may improve clinical assessment and management globally.

Registration

Clinicaltrials.gov (#NCT04403880).

Psychiatric symptoms in Long-COVID patients: a systematic review

Objective

People who have been infected by COVID-19 showing persistent symptoms after 4 weeks from recovery are thought to suffer from Long-COVID syndrome (LC). There is uncertainty on the clinical manifestations of LC. We undertook a systematic review to summarize the available evidence about the main psychiatric manifestations of LC.

Method

PubMed (Medline), Scopus, CINHAL, PsycINFO, and EMBASE were searched until May 2022. Studies reporting estimation of emerging psychiatric symptoms and/or psychiatric diagnoses among adult people with LC were included. Pooled prevalence for each psychiatric condition was calculated in absence of control groups to compare with.

Results

Thirty-three reports were included in the final selection, corresponding to 282,711 participants with LC. After 4 weeks from COVID-19 infection recovery, participants reported the following psychiatric symptoms: depression, anxiety, post-traumatic symptoms (PTS), cognitive and sleeping disturbances (i.e., insomnia or hypersomnia). The most common psychiatric manifestation resulted to be sleep disturbances, followed by depression, PTS, anxiety, and cognitive impairment (i.e., attention and memory deficits). However, some estimates were affected by important outlier effect played by one study. If study weight was not considered, the most reported condition was anxiety.

Conclusions

LC may have non-specific psychiatric manifestations. More research is needed to better define LC and to differentiate it from other post-infectious or post-hospitalization syndromes.

Systematic review registration

PROSPERO (CRD42022299408).

[Neurological forms of long COVID in adults: Critical approach]

Now recognized by health authorities, long COVID is identified as a frequent condition complicating the evolution of SARS-CoV-2 infection. Its polymorphic and sometimes disconcerting clinical expression raises questions about its mechanism. Patterns of clinical expression suggest extensive involvement of the nervous system through an almost ubiquitous cognitive complaint. This article reviews the neurological symptoms and forms of these patients, and the neuropsychological explorations aimed at objectifying a cognitive deficit. The studies published until now confronted with the clinical mode of expression, did not make it possible to define a deficit neuropsychological profile at the level of the groups, and evoked more a functional impairment than a lesion. However, each series mentions a small number of patients in whom a cognitive deficit is objectified. The uncertainties about the causes of the prolonged forms of COVID, the heterogeneity of the published studies, and the virtual absence of temporal evolution data should make one cautious about the interpretation of these data but should in no way delay or prevent taking into account care of these patients.

Prevalence of long COVID decreases for increasing COVID-19 vaccine uptake

Long COVID is a post-COVID-19 condition characterized by persistent symptoms that can develop after SARS-CoV-2 infection. Estimating and comparing its prevalence across countries is difficult, hindering the quantitative assessment of massive vaccination campaigns as a preventive measure. By integrating epidemiological, demographic and vaccination data, we first reconcile the estimates of long COVID prevalence in the U.K. and the U.S., and estimate a 7-fold yearly increase in the global median prevalence between 2020 and 2022. Second, we estimate that vaccines against COVID-19 decrease the prevalence of long COVID among U.S. adults by 20.9% (95% CI: -32.0%, -9.9%) and, from the analysis of 158 countries, by -15.7% (95% CI: -18.0%, -13.4%) among all who had COVID-19. Our population-level analysis complements the current knowledge from patients data and highlights how aggregated data from fully operational epidemic surveillance and monitoring can inform about the potential impact of long COVID on national and global public health in the next future.

Laboratory Findings and Biomarkers in Long COVID: What Do We Know So Far? Insights into Epidemiology, Pathogenesis, Therapeutic Perspectives and Challenges

Long COVID (LC) encompasses a constellation of long-term symptoms experienced by at least 10% of people after the initial SARS-CoV-2 infection, and so far it has affected about 65 million people. The etiology of LC remains unclear; however, many pathophysiological pathways may be involved, including viral persistence; a chronic, low-grade inflammatory response; immune dysregulation and a defective immune response; the reactivation of latent viruses; autoimmunity; persistent endothelial dysfunction and coagulopathy; gut dysbiosis; hormonal and metabolic dysregulation; mitochondrial dysfunction; and autonomic nervous system dysfunction. There are no specific tests for the diagnosis of LC, and clinical features including laboratory findings and biomarkers may not specifically relate to LC. Therefore, it is of paramount importance to develop and validate biomarkers that can be employed for the prediction, diagnosis and prognosis of LC and its therapeutic response, although this effort may be hampered by challenges pertaining to the non-specific nature of the majority of clinical manifestations in the LC spectrum, small sample sizes of relevant studies and other methodological issues. Promising candidate biomarkers that are found in some patients are markers of systemic inflammation, including acute phase proteins, cytokines and chemokines; biomarkers reflecting SARS-CoV-2 persistence, the reactivation of herpesviruses and immune dysregulation; biomarkers of endotheliopathy, coagulation and fibrinolysis; microbiota alterations; diverse proteins and metabolites; hormonal and metabolic biomarkers; and cerebrospinal fluid biomarkers. At present, there are only two reviews summarizing relevant biomarkers; however, they do not cover the entire umbrella of current biomarkers, their link to etiopathogenetic mechanisms or the diagnostic work-up in a comprehensive manner. Herein, we aim to appraise and synopsize the available evidence on the typical laboratory manifestations and candidate biomarkers of LC, their classification based on pathogenetic mechanisms and the main LC symptomatology in the frame of the epidemiological and clinical aspects of the syndrome and furthermore assess limitations and challenges as well as potential implications in candidate therapeutic interventions.

Microbiome and intestinal pathophysiology in post-acute sequelae of COVID-19

Long COVID, also known for post-acute sequelae of COVID-19, describes the people who have the signs and symptoms that continue or develop after the acute COVID-19 phase. Long COVID patients suffer from an inflammation or host responses towards the virus approximately 4 weeks after initial infection with the SARS CoV-2 virus and continue for an uncharacterized duration. Anyone infected with COVID-19 before could experience long-COVID conditions, including the patients who were infected with SARS CoV-2 virus confirmed by tests and those who never knew they had an infection early. People with long COVID may experience health problems from different types and combinations of symptoms over time, such as fatigue, dyspnea, cognitive impairments, and gastrointestinal (GI) symptoms (e.g., nausea, vomiting, diarrhea, decreased or loss of appetite, abdominal pain, and dysgeusia). The critical role of the microbiome in these GI symptoms and long COVID were reported in clinical patients and experimental models. Here, we provide an overall view of the critical role of the GI tract and microbiome in the development of long COVID, including the clinical GI symptoms in patients, dysbiosis, viral-microbiome interactions, barrier function, and inflammatory bowel disease patients with long COVID. We highlight the potential mechanisms and possible treatment based on GI health and microbiome. Finally, we discuss challenges and future direction in the long COVID clinic and research.

Association of Long COVID with housing insecurity in the United States, 2022-2023

Objectives

To assess the association of Long COVID with housing insecurity in the United States.

Methods

To compare the prevalence of 3 binary indicators of housing insecurity between people with Long COVID (symptoms > 3 months) and COVID-19 survivors who don't report long-term symptoms, we used survey-weighted regression models on 203,807 responses from the Household Pulse Survey, a representative cross-sectional survey of US households collected September 2022 - April 2023. Among people with Long COVID, we assessed whether functional impairment, current COVID-19 related symptoms, and symptom impact on day-today life were associated with a higher prevalence of housing insecurity.

Results

During the study period, 54,446 (27.2%) respondents with COVID-19 experienced symptoms lasting 3 months or longer, representing an estimated 27 million US adults. People with Long COVID were nearly twice as likely to experience significant difficulty with household expenses (Prevalence ratio [PR] 1.85, 95% CI 1.74-1.96), be behind on housing payments (PR 1.76, 95% CI 1.57-1.99), and face likely eviction or foreclosure (PR 2.12, 95% CI 1.58-2.86). Functional limitation and current symptoms which impact day-to-day life were associated with higher prevalence of housing insecurity.

Conclusions

Compared with COVID-19 survivors who don't experience long-term symptoms, people with Long COVID are more likely to report indicators housing insecurity, particularly those with functional limitations and long-term COVID-19 related symptoms impacting day-today life. Policies are needed to support people living with chronic illnesses following SARS-CoV-2 infection.

Natural history of long-COVID in a nationwide, population cohort study

Previous studies on the natural history of long-COVID have been few and selective. Without comparison groups, disease progression cannot be differentiated from symptoms originating from other causes. The Long-COVID in Scotland Study (Long-CISS) is a Scotland-wide, general population cohort of adults who had laboratory-confirmed SARS-CoV-2 infection matched to PCR-negative adults. Serial, self-completed, online questionnaires collected information on pre-existing health conditions and current health six, 12 and 18 months after index test. Of those with previous symptomatic infection, 35% reported persistent incomplete/no recovery, 12% improvement and 12% deterioration. At six and 12 months, one or more symptom was reported by 71.5% and 70.7% respectively of those previously infected, compared with 53.5% and 56.5% of those never infected. Altered taste, smell and confusion improved over time compared to the never infected group and adjusted for confounders. Conversely, late onset dry and productive cough, and hearing problems were more likely following SARS-CoV-2 infection.

Changes in Quality of Life Following SARS-CoV-2 Infection Among Jewish and Arab Populations in Israel: A Cross-Sectional Study

Objectives: The long-term impact of COVID-19 on health inequalities is under-researched. We investigated changes in health-related inequalities following SARS-CoV-2 infection between the Jewish majority and the Arab/Druze minority in Israel. Methods: Patients with a positive SARS-CoV-2 RT-PCR test processed from one of the Northern-Israeli government hospitals between 03/2021 and 05/2022 were invited to participate. We collected socio-demographic, COVID-19-related, and health-related quality of life (HRQoL) information using a validated questionnaire. We compared pre- and post COVID-19 HRQoL changes between Jews and Arabs/Druze, up to 12+ months post-infection using an adjusted linear regression model. Results: Among the 881 included participants the average post-COVID HRQoL score was lower among Arabs/Druze than Jews (0.83 vs. 0.88; p = 0.005). Until 12 months post-infection, HRQoL changes were similar for Arabs/Druze and Jews. After 12 months, HRQoL dropped significantly more among Arabs/Druze than among Jews (0.11 points difference between the groups; p = 0.014), despite adjusting for socioeconomic variables. Conclusion: 12 months post-infection, COVID-19 affected the HRQoL of Arabs/Druze more than Jews, with the gap not fully explained by socio-economic differences. The COVID-19 pandemic may widen pre-existing long-term health inequalities.

Use of latent class analysis and patient reported outcome measures to identify distinct long COVID phenotypes: A longitudinal cohort study

OBJECTIVES

We sought to 1) identify long COVID phenotypes based on patient reported outcome measures (PROMs) and 2) determine whether the phenotypes were associated with quality of life (QoL) and/or lung function.

METHODS

This was a longitudinal cohort study of hospitalized and non-hospitalized patients from March 2020 to January 2022 that was conducted across 4 Post-COVID Recovery Clinics in British Columbia, Canada. Latent class analysis was used to identify long COVID phenotypes using baseline PROMs (fatigue, dyspnea, cough, anxiety, depression, and post-traumatic stress disorder). We then explored the association between the phenotypes and QoL (using the EuroQoL 5 dimensions visual analogue scale [EQ5D VAS]) and lung function (using the diffusing capacity of the lung for carbon monoxide [DLCO]).

RESULTS

There were 1,344 patients enrolled in the study (mean age 51 ±15 years; 780 [58%] were females; 769 (57%) were of a non-White race). Three distinct long COVID phenotypes were identified: Class 1) fatigue and dyspnea, Class 2) anxiety and depression, and Class 3) fatigue, dyspnea, anxiety, and depression. Class 3 had a significantly lower EQ5D VAS at 3 (50±19) and 6 months (54 ± 22) compared to Classes 1 and 2 (p<0.001). The EQ5D VAS significantly improved between 3 and 6 months for Class 1 (median difference of 6.0 [95% CI, 4.0 to 8.0]) and Class 3 (median difference of 5.0 [95% CI, 0 to 8.5]). There were no differences in DLCO between the classes.

CONCLUSIONS

There were 3 distinct long COVID phenotypes with different outcomes in QoL between 3 and 6 months after symptom onset. These phenotypes suggest that long COVID is a heterogeneous condition with distinct subpopulations who may have different outcomes and warrant tailored therapeutic approaches.

One-Year Temporal Changes in Long COVID Prevalence and Characteristics: A Systematic Review and Meta-Analysis

OBJECTIVES

This study aimed to explore the 1-year temporal change in prevalence, variety, and potential risk factors of long COVID symptoms and to further predict the prognostic trends of long COVID.

METHODS

We searched electronic databases for related studies published from January 2020 to February 2022 and conducted 1-group meta-analysis and locally weighted regression to explore the monthly temporal change in the prevalence of each long COVID symptom in 1-year follow-up period.

RESULTS

A total of 137 studies were included in meta-analysis, including 134 093 participants. The temporal change of any long COVID symptom showed a steep decrease initially (from 92% at acute phase to 55% at 1-month follow-up), followed by stabilization at approximately 50% during 1-year follow-up. Six months or more after the acute phase, the odds ratio of population characteristic-related factors increased, such as female (from 1.62 to 1.82), whereas the odds ratio value of acute phase-related factors (severe or critical cases and hospitalization) decreased. As for specific symptoms, approximately two-thirds of the symptoms did not significantly reduce during the 1-year follow-up, and the neuropsychiatric symptoms showed a higher long-term prevalence (approximately 25%) and longer persistence than physical symptoms.

CONCLUSIONS

The temporal changes in the prevalence and characteristics speculate that long COVID may persist longer than expected. In particular, we should pay more attention to neuropsychiatric symptoms and other symptoms for which there is no significant downward trend in prevalence. The influence of acute phase-related factors for long COVID gradually decreases over time, whereas the influence of population characteristic-related factors gradually increases.

Unraveling pathophysiologic mechanisms contributing to symptoms in patients with post-acute sequelae of COVID-19 (PASC): A retrospective study

Patients with post-acute sequelae of COVID-19 (PASC) present with a decrease in physical fitness. The aim of this paper is to reveal the relations between the remaining symptoms, blood volume distribution, exercise tolerance, static and dynamic lung volumes, and overall functioning. Patients with PASC were retrospectively studied. Pulmonary function tests (PFT), 6-minute walk test (6MWT), and cardiopulmonary exercise test were performed. Chest CT was taken and quantified. Patients were divided into two groups: minor functional limitations (MFL) and severe functional limitations (SFL) based on the completed Post-COVID-19 Functional Status scale (PCFS). Twenty one patients (3 M; 18 FM), mean age 44 (IQR 21) were studied. Eighteen completed the PCFS (8 MFL; 10 SFL). VO2 max was suboptimal in both groups (not significant). 6MWT was significantly higher in MFL-group (p = 0.043). Subjects with SFL, had significant lower TLC (p = 0.029). The MFL-group had more air trapping (p = 0.036). Throughout the sample, air trapping correlated significantly with residual volume (RV) in L (p < 0.001). An increase in air trapping was related to an increase in BV5 (p < 0.001). Mean BV5 was 65% (IQR 5%). BV5% in patients with PASC was higher than in patients with acute COVID-19 infection. This increase in BV5% in patients with PASC is thought to be driven by the air trapping in the lobes. This study reveals that symptoms are more driven by occlusion of the small airways. Patients with more physical complaints have significantly lower TLC. All subjects encounter physical limitations as indicated by suboptimal VO2 max. Treatment should focus on opening or re-opening of small airways by recruiting alveoli.

Prevalence and risk factors of long COVID 6-12 months after infection with the Omicron variant among nonhospitalized patients in Hong Kong

Long COVID has been reported among patients with COVID-19, but little is known about the prevalence and risk factors associated with long COVID 6-12 months after infection with the Omicron variant. This is a large-scale retrospective study. A total of 6242 out of 12 950 nonhospitalized subjects of all ages with SARS-CoV-2 infection (confirmed by polymerase chain reaction/rapid antigen test) during the Omicron dominant outbreak (December 31, 2021-May 6, 2022) in Hong Kong were included. Prevalence of long COVID, frequencies of symptoms, and risk factors were analyzed. Three thousand four hundred and thirty (55.0%) subjects reported at least one long COVID symptom. The most reported symptom was fatigue (1241, 36.2%). Female gender, middle age, obesity, comorbidities, vaccination after infection, having more symptoms, and presenting fatigue/chest tightness/headache/diarrhea in the acute stage of illness were identified as associated risk factors for long COVID. Patients who had received three or more doses of vaccine were not associated with a lower risk of long COVID (adjusted odds ratio 1.105, 95% confidence interval 0.985-1.239, p = 0.088). Among patients with at least three doses of vaccine, there was no significant difference in the risk of long COVID between the CoronaVac vaccine and BNT162b2 vaccine (p > 0.05). Omicron infection can lead to long COVID in a significant proportion of nonhospitalized patients 6-12 months after infection. Further investigation is needed to uncover the mechanisms underlying the development of long COVID and determine the impact of various risk factors such as vaccines.

Prophylactic rivaroxaban in the early post-discharge period reduces the rates of hospitalization for atrial fibrillation and incidence of sudden cardiac death during long-term follow-up in hospitalized COVID-19 survivors

Introduction: While acute Coronavirus disease 2019 (COVID-19) affects the cardiovascular (CV) system according to recent data, an increased CV risk has been reported also during long-term follow-up (FU). In addition to other CV pathologies in COVID-19 survivors, an enhanced risk for arrhythmic events and sudden cardiac death (SCD) has been observed. While recommendations on post-discharge thromboprophylaxis are conflicting in this population, prophylactic short-term rivaroxaban therapy after hospital discharge showed promising results. However, the impact of this regimen on the incidence of cardiac arrhythmias has not been evaluated to date. Methods: To investigate the efficacy of this therapy, we conducted a single center, retrospective analysis of 1804 consecutive, hospitalized COVID-19 survivors between April and December 2020. Patients received either a 30-day post-discharge thromboprophylaxis treatment regimen using rivaroxaban 10 mg every day (QD) (Rivaroxaban group (Riva); n = 996) or no thromboprophylaxis (Control group (Ctrl); n = 808). Hospitalization for new atrial fibrillation (AF), new higher-degree Atrioventricular-block (AVB) as well as incidence of SCD were investigated in 12-month FU [FU: 347 (310/449) days]. Results: No differences in baseline characteristics (Ctrl vs Riva: age: 59.0 (48.9/66.8) vs 57 (46.5/64.9) years, p = n.s.; male: 41.5% vs 43.7%, p = n.s.) and in the history of relevant CV-disease were observed between the two groups. While hospitalizations for AVB were not reported in either group, relevant rates of hospitalizations for new AF (0.99%, n = 8/808) as well as a high rate of SCD events (2.35%, n = 19/808) were seen in the Ctrl. These cardiac events were attenuated by early post-discharge prophylactic rivaroxaban therapy (AF: n = 2/996, 0.20%, p = 0.026 and SCD: n = 3/996, 0.30%, p < 0.001) which was also observed after applying a logistic regression model for propensity score matching (AF: χ ²-statistics = 6.45, p = 0.013 and SCD: χ ²-statistics = 9.33, p = 0.002). Of note, no major bleeding complications were observed in either group. Conclusion: Atrial arrhythmic and SCD events are present during the first 12 months after hospitalization for COVID-19. Extended prophylactic Rivaroxaban therapy after hospital discharge could reduce new onset of AF and SCD in hospitalized COVID-19 survivors.

Clustering Analysis Identified Three Long COVID Phenotypes and Their Association with General Health Status and Working Ability

BACKGROUND/AIM

This study aimed to distinguish different phenotypes of long COVID through the post-COVID syndrome (PCS) score based on long-term persistent symptoms following COVID-19 and evaluate whether these symptoms affect general health and work ability. In addition, the study identified predictors for severe long COVID.

METHOD

This cluster analysis included cross-sectional data from three cohorts of patients after COVID-19: non-hospitalized (n = 401), hospitalized (n = 98) and those enrolled at the post-COVID outpatient's clinic (n = 85). All the subjects responded to the survey on persistent long-term symptoms and sociodemographic and clinical factors. K-Means cluster analysis and ordinal logistic regression were used to create PCS scores that were used to distinguish patients' phenotypes.

RESULTS

506 patients with complete data on persistent symptoms were divided into three distinct phenotypes: none/mild (59%), moderate (22%) and severe (19%). The patients with severe phenotype, with the predominating symptoms were fatigue, cognitive impairment and depression, had the most reduced general health status and work ability. Smoking, snuff, body mass index (BMI), diabetes, chronic pain and symptom severity at COVID-19 onset were factors predicting severe phenotype.

CONCLUSION

This study suggested three phenotypes of long COVID, where the most severe was associated with the highest impact on general health status and working ability. This knowledge on long COVID phenotypes could be used by clinicians to support their medical decisions regarding prioritizing and more detailed follow-up of some patient groups.

Social inequalities and long-term health impact of COVID-19 in Belgium: protocol of the HELICON population data linkage

INTRODUCTION

Data linkage systems have proven to be a powerful tool in support of combating and managing the COVID-19 pandemic. However, the interoperability and the reuse of different data sources may pose a number of technical, administrative and data security challenges.

METHODS AND ANALYSIS

This protocol aims to provide a case study for linking highly sensitive individual-level information. We describe the data linkages between health surveillance records and administrative data sources necessary to investigate social health inequalities and the long-term health impact of COVID-19 in Belgium. Data at the national institute for public health, Statistics Belgium and InterMutualistic Agency are used to develop a representative case-cohort study of 1.2 million randomly selected Belgians and 4.5 million Belgians with a confirmed COVID-19 diagnosis (PCR or antigen test), of which 108 211 are COVID-19 hospitalised patients (PCR or antigen test). Yearly updates are scheduled over a period of 4 years. The data set covers inpandemic and postpandemic health information between July 2020 and January 2026, as well as sociodemographic characteristics, socioeconomic indicators, healthcare use and related costs. Two main research questions will be addressed. First, can we identify socioeconomic and sociodemographic risk factors in COVID-19 testing, infection, hospitalisations and mortality? Second, what is the medium-term and long-term health impact of COVID-19 infections and hospitalisations? More specific objectives are (2a) To compare healthcare expenditure during and after a COVID-19 infection or hospitalisation; (2b) To investigate long-term health complications or premature mortality after a COVID-19 infection or hospitalisation; and (2c) To validate the administrative COVID-19 reimbursement nomenclature. The analysis plan includes the calculation of absolute and relative risks using survival analysis methods.

ETHICS AND DISSEMINATION

This study involves human participants and was approved by Ghent University hospital ethics committee: reference B.U.N. 1432020000371 and the Belgian Information Security Committee: reference Beraadslaging nr. 22/014 van 11 January 2022, available via https://www.ehealth.fgov.be/ehealthplatform/file/view/AX54CWc4Fbc33iE1rY5a?filename=22-014-n034-HELICON-project.pdf. Dissemination activities include peer-reviewed publications, a webinar series and a project website.The pseudonymised data are derived from administrative and health sources. Acquiring informed consent would require extra information on the subjects. The research team is prohibited from gaining additional knowledge on the study subjects by the Belgian Information Security Committee's interpretation of the Belgian privacy framework.

Post-COVID-19 syndrome and diabetes mellitus: a propensity-matched analysis of the International HOPE-II COVID-19 Registry

Background

Diabetes mellitus (DM) is one of the most frequent comorbidities in patients suffering from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with a higher rate of severe course of coronavirus disease (COVID-19). However, data about post-COVID-19 syndrome (PCS) in patients with DM are limited.

Methods

This multicenter, propensity score-matched study compared long-term follow-up data about cardiovascular, neuropsychiatric, respiratory, gastrointestinal, and other symptoms in 8,719 patients with DM to those without DM. The 1:1 propensity score matching (PSM) according to age and sex resulted in 1,548 matched pairs.

Results

Diabetics and nondiabetics had a mean age of 72.6 ± 12.7 years old. At follow-up, cardiovascular symptoms such as dyspnea and increased resting heart rate occurred less in patients with DM (13.2% vs. 16.4%; p = 0.01) than those without DM (2.8% vs. 5.6%; p = 0.05), respectively. The incidence of newly diagnosed arterial hypertension was slightly lower in DM patients as compared to non-DM patients (0.5% vs. 1.6%; p = 0.18). Abnormal spirometry was observed more in patients with DM than those without DM (18.8% vs. 13; p = 0.24). Paranoia was diagnosed more frequently in patients with DM than in non-DM patients at follow-up time (4% vs. 1.2%; p = 0.009). The incidence of newly diagnosed renal insufficiency was higher in patients suffering from DM as compared to patients without DM (4.8% vs. 2.6%; p = 0.09). The rate of readmission was comparable in patients with and without DM (19.7% vs. 18.3%; p = 0.61). The reinfection rate with COVID-19 was comparable in both groups (2.9% in diabetics vs. 2.3% in nondiabetics; p = 0.55). Long-term mortality was higher in DM patients than in non-DM patients (33.9% vs. 29.1%; p = 0.005).

Conclusions

The mortality rate was higher in patients with DM type II as compared to those without DM. Readmission and reinfection rates with COVID-19 were comparable in both groups. The incidence of cardiovascular symptoms was higher in patients without DM.

Effectiveness of a telerehabilitation intervention using ReCOVery APP of long COVID patients: a randomized, 3-month follow-up clinical trial

The main objective of this study is to analyze the clinical efficacy of telerehabilitation in the recovery of Long COVID patients through ReCOVery APP for 3 months, administered in the Primary Health Care context. The second objective is to identify significant models associated with an improvement in the study variables. An open-label randomized clinical trial was conducted using two parallel groups of a total of 100 Long COVID patients. The first group follows the treatment as usual methods established by their general practitioner (control group) and the second follows the same methods and also uses ReCOVery APP (intervention group). After the intervention, no significant differences were found in favour of the group intervention. Regarding adherence, 25% of the participants made significant use of the APP. Linear regression model establishes that the time of use of ReCOVery APP predicts an improvement in physical function (b = 0.001; p = 0.005) and community social support (b = 0.004; p = 0.021). In addition, an increase in self-efficacy and health literacy also contribute to improving cognitive function (b = 0.346; p = 0.001) and reducing the number of symptoms (b = 0.226; p = 0.002), respectively. In conclusion, the significant use of ReCOVery APP can contribute to the recovery of Long COVID patients. Trial Registration No.: ISRCTN91104012.

Comparative study of quality of life 9 months post-COVID-19 infection with SARS-CoV-2 of varying degrees of severity: impact of hospitalization vs. outpatient treatment

Purpose

This experimental study was conducted during the post-COVID-19 period to investigate the relationship between the quality of life 9 months after and the severity of the SARS-CoV-2 infection in two scenarios: hospitalization (with/without medical oxygen) and outpatient treatment.

Methods

We employed the EQ-5D-5L Quality of Life tests and the PSQI as a survey to evaluate respondents' quality of life 9 months after a previous SARS-CoV-2 infection of varying severity.

Results

We identified a clear difference in the quality of life of respondents, as measured on the 100-point scale of the EQ-5D-5L test, which was significantly lower 9 months after a previous SARS-CoV-2 infection for Group 1 (n = 14), respondents who had received medical attention for SARS-CoV-2 infection in a hospital with oxygen treatment, compared to those with the SARS-CoV-2 infection who were treated without oxygen treatment (Group 2) (n = 12) and those who were treated on an outpatient basis (Group 3) (n = 13) (H = 7.08 p = 0.029). There were no intergroup differences in quality of life indicators between hospitalized patients (Group 2) and groups 1 and 3. PSQI survey results showed that "mobility," "self-care," "daily activities," "pain/discomfort," and "anxiety/ depression" did not differ significantly between the groups, indicating that these factors were not associated with the severity of the SARS-CoV-2 infection. On the contrary, the respondents demonstrated significant inter-group differences (H = 7.51 p = 0.023) and the interdependence of respiratory difficulties with the severity of clinically diagnosed SARS-CoV-2 infection. This study also demonstrated significant differences in the values of sleep duration, sleep disorders, and daytime sleepiness indicators between the three groups of respondents, which indicate the influence of the severity of the infection. The PSQI test results revealed significant differences in "bedtime" (H = 6.00 p = 0.050) and "wake-up time" (H = 11.17 p = 0.004) between Groups 1 and 3 of respondents. At 9 months after COVID-19, respondents in Group 1 went to bed at a later time (pp = 0.02727) and woke up later (p = 0.003) than the respondents in Group 3.

Conclusion

This study is the first of its kind in the current literature to report on the quality of life of respondents 9 months after being diagnosed with COVID-19 and to draw comparisons between cohorts of hospitalized patients who were treated with medical oxygen vs. the cohorts of outpatient patients. The study's findings regarding post-COVID-19 quality of life indicators and their correlation with the severity of the SARS-CoV-2 infection can be used to categorize patients for targeted post-COVID-19 rehabilitation programs.

Use of machine learning to assess the prognostic utility of radiomic features for in-hospital COVID-19 mortality

As portable chest X-rays are an efficient means of triaging emergent cases, their use has raised the question as to whether imaging carries additional prognostic utility for survival among patients with COVID-19. This study assessed the importance of known risk factors on in-hospital mortality and investigated the predictive utility of radiomic texture features using various machine learning approaches. We detected incremental improvements in survival prognostication utilizing texture features derived from emergent chest X-rays, particularly among older patients or those with a higher comorbidity burden. Important features included age, oxygen saturation, blood pressure, and certain comorbid conditions, as well as image features related to the intensity and variability of pixel distribution. Thus, widely available chest X-rays, in conjunction with clinical information, may be predictive of survival outcomes of patients with COVID-19, especially older, sicker patients, and can aid in disease management by providing additional information.

"We're drowning and we're alone": a qualitative study of the lived experience of people experiencing persistent post-COVID-19 symptoms

BACKGROUND

The "long tail" of the COVID-19 pandemic will be reflected in disabling symptoms that persist, fluctuate or recur for extended periods for an estimated 20%-30% of those who had a SARS-CoV-2 infection; development of effective interventions to address these symptoms must account for the realities faced by these patients. We sought to describe the lived experience of patients living with persistent post-COVID-19 symptoms.

METHODS

We conducted a qualitative study, using interpretive description, of the lived experiences of adults experiencing persistent post-COVID-19 symptoms. We collected data from in-depth, semistructured virtual focus groups in February and March 2022. We used thematic analysis to analyze the data and met with several participants twice for respondent validation.

RESULTS

The study included 41 participants (28 females) from across Canada with a mean age of 47.9 years and mean time since initial SARS-CoV-2 infection of 15.8 months. Four overarching themes were identified: the unique burdens of living with persistent post-COVID-19 symptoms; the complex nature of patient work in managing symptoms and seeking treatment during recovery; erosion of trust in the health care system; and the process of adaptation, which included taking charge and transformed self-identity.

INTERPRETATION

Living with persistent post-COVID-19 symptoms within a health care system ill-equipped to provide needed resources profoundly challenges the ability of survivors to restore their well-being. Whereas policy and practice increasingly emphasize the importance of self-management within the context of post-COVID-19 symptoms, new investments that enhance services and support patient capacity are required to promote better outcomes for patients, the health care system and society.

Serum KL-6 levels predict clinical outcomes and are associated with MUC1 polymorphism in Japanese patients with COVID-19

BACKGROUND

Krebs von den Lungen-6 (KL-6) is a known biomarker for diagnosis and monitoring of interstitial lung diseases. However, the role of serum KL-6 and the mucin 1 (MUC1) variant (rs4072037) in COVID-19 outcomes remains to be elucidated. We aimed to evaluate the relationships among serum KL-6 levels, critical outcomes and the MUC1 variant in Japanese patients with COVID-19.

METHODS

This is a secondary analysis of a multicentre retrospective study using data from the Japan COVID-19 Task Force collected from February 2020 to November 2021, including 2226 patients with COVID-19 whose serum KL-6 levels were measured. An optimal serum KL-6 level cut-off to predict critical outcomes was determined and used for multivariable logistic regression analysis. Furthermore, the relationship among the allele dosage of the MUC1 variant, calculated from single nucleotide polymorphism typing data of genome-wide association studies using the imputation method, serum KL-6 levels and COVID-19 critical outcomes was evaluated.

RESULTS

Serum KL-6 levels were significantly higher in patients with COVID-19 with critical outcomes (511±442 U/mL) than those without (279±204 U/mL) (p<0.001). Serum KL-6 levels ≥304 U/mL independently predicted critical outcomes (adjusted OR (aOR) 3.47, 95% CI 2.44 to 4.95). Moreover, multivariable logistic regression analysis with age and sex indicated that the MUC1 variant was independently associated with increased serum KL-6 levels (aOR 0.24, 95% CI 0.28 to 0.32) but not significantly associated with critical outcomes (aOR 1.11, 95% CI 0.80 to 1.54).

CONCLUSION

Serum KL-6 levels predicted critical outcomes in Japanese patients with COVID-19 and were associated with the MUC1 variant. Therefore, serum KL-6 level is a potentially useful biomarker of critical COVID-19 outcomes.

Impairments following COVID-19 infection: manifestations and investigations of related factors

The COVID-19 pandemic had a major global impact on the health and wellbeing for many individuals. Even though the infection rates have gone down due to the availability of vaccines, the consequences of the disease are still present due to persistent symptoms among individuals. The aim of the current study was to map long-term impairments in individuals infected with COVID-19 by applying the framework of the World Health Organization's International Classification of Functioning, Disability and Health (ICF) and also investigate the factors related to the context of an individual's life influencing the impairments. A web-survey that targeted individuals that had been infected with COVID-19 was used. The survey included a range of measures covering contextual factors and factors related to body functions and structures and post-COVID impairments. A total of 501 individuals were included in the study (with a mean age of 47.6 years). 96% of the respondents reported at least one moderate-to-severe impairment due to COVID-19 infection and the most frequent one was fatigue. In that, 79.6% and 86.9% of the study sample reported moderate-to-severe brain fatigue and tiredness or lack of energy, respectively. Severity of COVID-19 infection appeared as the strongest risk factor for post-COVID impairments. Based on the results, interventions can be tailored to help individuals with post-COVID-19 condition. This could be one way lessening the effect of COVID-19 on health care and society as a whole.

A Review of Neurological Symptoms in Long COVID and Clinical Management

Long COVID is a clinical diagnosis generally referring to the persistence or development of new symptoms, affecting multiple organ systems after SARS-CoV-2 COVID-19 infection. Long COVID is thought to affect ∼20% of people after infection, including all age ranges and severity of infection. Fatigue, postexertional malaise, and respiratory and cardiac symptoms are commonly described. Neurological symptoms such as cognitive changes, sensory disturbances, headaches, and dysautonomia are common as well. The underlying pathophysiology remains unclear but immune dysregulation, autoimmunity, persistent viral reservoirs, and microvascular dysfunction have been implicated. As there are no tests at this time to diagnose long COVID, work-up should be focused on assessing reversible or treatable causes of symptoms. Furthermore, no treatments for long COVID currently exist, and management remains focused on a multimodal approach and symptom management, with many people showing improvement in symptoms over time.

Sex and age affect acute and persisting COVID-19 illness

Long COVID is associated with neurological and neuropsychiatric manifestations. We conducted an observational study on 97 patients with prior SARS-CoV-2 infection and persisting cognitive complaints that presented to the University Health Network Memory Clinic between October 2020 and December 2021. We assessed the main effects of sex, age, and their interaction on COVID-19 symptoms and outcomes. We also examined the relative contribution of demographics and acute COVID-19 presentation (assessed retrospectively) on persistent neurological symptoms and cognition. Among our cohort, males had higher hospitalization rates than females during the acute COVID-19 illness (18/35 (51%) vs. 15/62 (24%); P = .009). Abnormal scores on cognitive assessments post-COVID were associated with older age (AOR = 0.84; 95% CI 0.74-0.93) and brain fog during initial illness (AOR = 8.80; 95% CI 1.76-65.13). Female sex (ARR = 1.42; 95% CI 1.09-1.87) and acute shortness of breath (ARR = 1.41; 95% CI 1.09-1.84) were associated with a higher risk of experiencing more persistent short-term memory symptoms. Female sex was the only predictor associated with persistent executive dysfunction (ARR = 1.39; 95% CI 1.12-1.76) and neurological symptoms (ARR = 1.66; 95% CI 1.19-2.36). Sex differences were evident in presentations and cognitive outcomes in patients with long COVID.

Cellular and molecular biomarkers of long COVID: a scoping review

BACKGROUND

Long-COVID (LC) encompasses diverse symptoms lasting months after the initial SARS-CoV-2 infection. Symptoms can be debilitating and affect the quality of life of individuals with LC and their families. Although the symptoms of LC are well described, the aetiology of LC remains unclear, and consequently, patients may be underdiagnosed. Identification of LC specific biomarkers is therefore paramount for the diagnosis and clinical management of the syndrome. This scoping review describes the molecular and cellular biomarkers that have been identified to date with potential use for diagnosis or prediction of LC.

METHODS

This review was conducted using the Joanna Briggs Institute (JBI) Methodology for Scoping Reviews. A search was executed in the MEDLINE and EMBASE databases, as well as in the grey literature for original studies, published until October 5th, 2022, reporting biomarkers identified in participants with LC symptoms (from all ages, ethnicities, and sex), with a previous infection of SARS-CoV-2. Non-English studies, cross-sectional studies, studies without a control group, and pre-prints were excluded. Two reviewers independently evaluated the studies, extracted population data and associated biomarkers.

FINDINGS

23 cohort studies were identified, involving 2163 LC patients [median age 51.8 years, predominantly female sex (61.10%), white (75%), and non-vaccinated (99%)]. A total of 239 candidate biomarkers were identified, consisting mainly of immune cells, immunoglobulins, cytokines, and other plasma proteins. 19 of the 239 candidate biomarkers identified were evaluated by the authors, by means of receiver operating characteristic (ROC) curves.

INTERPRETATION

Diverse cellular and molecular biomarkers for LC have been proposed. Validation of candidate biomarkers in independent samples should be prioritized. Modest reported performance (particularly in larger studies) suggests LC may encompass many distinct aetiologies, which should be explored e.g., by stratifying by symptom clusters and/or sex.

FUNDING

Dr. Tebbutt has received funding from the Canadian Institutes of Health Research (177747) to conduct this work. The funding source was not involved in this scoping review, or in the decision to submit this manuscript for publication.

Long-Term Consequences of COVID-19: A 1-Year Analysis

Long-lasting symptoms after SARS-CoV-2 infection have been described many times in the literature and are referred to as Long COVID. In this prospective, longitudinal, monocentric, observational study, we collected the health complaints of 474 patients (252 ambulatory and 222 hospitalized) at Lausanne University Hospital 1 year after COVID-19 diagnosis. Using a self-reported health survey, we explored cardiopulmonary, vascular, neurological, and psychological complaints. Our results show that age, Charlson comorbidity index, and smoking habits were associated with hospital admission. Regarding the vascular system, we found that having had thromboembolism before SARS-CoV-2 infection was significantly associated with a higher risk of recurrence of thromboembolism at 1 year. In the neurologic evaluation, the most frequent symptom was fatigue, which was observed in 87.5% of patients, followed by “feeling slowed down”, headache, and smell disturbance in 71.5%, 68.5%, and 60.7% of cases, respectively. Finally, our cohort subjects scored higher overall in the STAI, CESD, Maastricht, and PSQI scores (which measure anxiety, depression, fatigue, and sleep, respectively) than the healthy population. Using cluster analysis, we identified two phenotypes of patients prone to developing Long COVID. At baseline, CCS score, prior chronic disease, stroke, and atrial fibrillation were associated with Long COVID. During COVID infection, mechanical ventilation and five neurological complaints were also associated with Long COVID. In conclusion, this study confirms the wide range of symptoms developed after COVID with the involvement of all the major systems. Early identification of risk factors associated with the development of Long COVID could improve patient follow-up; nevertheless, the low specificity of these factors remains a challenge to building a systematic approach.

COVID-19 and autoimmune diseases: is there a connection?

PURPOSE OF REVIEW

This review summarizes current evidence on the potential link between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and autoimmunity.

RECENT FINDINGS

Several viral infections are potential triggers of reactive and autoimmune diseases by inducing type II and type IV hypersensitivity reactions. Recent evidence demonstrated that SARS-CoV-2 infection is not an exception, triggering the production of tissue-specific autoantibodies during the acute phase of coronavirus disease 2019 (COVID-19) and leading to autoimmune diseases development as long-term complication. The significant immune dysregulation with cytokine storm and organ damage observed in patients with severe to critical COVID-19 is considered the main mechanism explaining the high levels of autoantibodies, which are also implicated in disease severity and the need for an intensive care assessment. Multisystem inflammatory syndrome in children (MIS-C) is an immune-mediated disease where the recent viral infection leads to systemic inflammation, as already observed in other reactive and autoimmune diseases.

SUMMARY

Autoimmunity may be a complication of SAR-CoV-2 infection. Understanding the pathogenesis of autoimmune manifestations in COVID-19 might help prevent the incidence or exacerbation of autoimmune disorders and design better and more efficient treatment strategies in children and adult populations.

Screening and Management of Malnutrition in Total Joint Arthroplasty

Malnutrition is an increasingly prevalent problem in patients undergoing total joint arthroplasty (TJA). Increased risks associated with TJA in the setting of malnourishment have been well documented. Standardized scoring systems in addition to laboratory parameters such as albumin, prealbumin, transferrin, and total lymphocyte count have been developed to identify and evaluate malnourished patients. Despite an abundance of recent literature, there is no consensus on the best approach for screening TJA patients from a nutritional standpoint. Although there are a variety of treatment options, including nutritional supplements, nonsurgical weight loss therapies, bariatric surgery, and the involvement of dieticians and nutritionists, the effect of these interventions on TJA outcomes has not been well characterized. This overview of the most current literature aims to provide a clinical framework for approaching nutrition status in arthroplasty patients. A comprehensive understanding of the tools available for managing malnourishment will facilitate improved arthroplasty care.

Causal effects of COVID-19 on cancer risk: A Mendelian randomization study

In contemporary literature, little attention has been paid to the association between coronavirus disease-2019 (COVID-19) and cancer risk. We performed the Mendelian randomization (MR) to investigate the causal associations between the three types of COVID-19 exposures (critically ill COVID-19, hospitalized COVID-19, and respiratory syndrome coronavirus 2 (SARS-CoV-2) infection) and 33 different types of cancers of the European population. The results of the inverse-variance-weighted model indicated that genetic liabilities to critically ill COVID-19 had suggestive causal associations with the increased risk for HER2-positive breast cancer (odds ratio [OR] = 1.0924; p-value = 0.0116), esophageal cancer (OR = 1.0004; p-value = 0.0226), colorectal cancer (OR = 1.0010; p-value = 0.0242), stomach cancer (OR = 1.2394; p-value = 0.0331), and colon cancer (OR = 1.0006; p-value = 0.0453). The genetic liabilities to hospitalized COVID-19 had suggestive causal associations with the increased risk for HER2-positive breast cancer (OR = 1.1096; p-value = 0.0458), esophageal cancer (OR = 1.0005; p-value = 0.0440) as well as stomach cancer (OR = 1.3043; p-value = 0.0476). The genetic liabilities to SARS-CoV-2 infection had suggestive causal associations with the increased risk for stomach cancer (OR = 2.8563; p-value = 0.0019) but with the decreasing risk for head and neck cancer (OR = 0.9986, p-value = 0.0426). The causal associations of the above combinations were robust through the test of heterogeneity and pleiotropy. Together, our study indicated that COVID-19 had causal effects on cancer risk.

Post-COVID-19-associated multiorgan complications or "long COVID" with literature review and management strategy discussion: A meta-analysis

Objective

To investigate the post-COVID-19 long-term complications or long COVID of various organ systems in patients after 3 months of the infection, specifically before the Omicron variant, with comparative literature analysis.

Methods

A systemic literature search and meta-analysis were conducted using multiple electronic databases (PubMed, Scopus, Cochrane library) with predefined search terms to identify eligible articles. Eligible studies reported long-term complications of COVID-19 infection before the Omicron variant infection. Case reports, case series, observational studies with cross-sectional or prospective research design, case-control studies, and experimental studies that reported post-COVID-19 complications were included. The complications reported after 3 months after the recovery from COVID-19 infection were included in the study.

Results

The total number of studies available for analysis was 34. The effect size (ES) for neurological complications was 29% with 95% confidence interval (CI): 19%-39%. ES for psychiatric complications was 24% with 95% CI: 7%-41%. ES was 9% for cardiac outcomes, with a 95% CI of 1%-18%. ES was 22%, 95% CI: 5%-39% for the gastrointestinal outcome. ES for musculoskeletal symptoms was 18% with 95% CI: 9%-28%. ES for pulmonary complications was 28% with 95% CI: 18%-37%. ES for dermatological complications was 25%, with a 95% CI of 23%-26%. ES for endocrine outcomes was 8%, with a 95% CI of 8%-9%. ES size for renal outcomes was 3% with a 95% CI of 1%-7%. At the same time, other miscellaneous uncategorized outcomes had ES of 39% with 95% CI of 21%-57%. Apart from analyzing COVID-19 systemic complications outcomes, the ES for hospitalization and intensive care unit admissions were found to be 4%, 95% CI: 0%-7%, and 11% with 95% CI: 8%-14%.

Conclusion

By acquiring the data and statistically analyzing the post-COVID-19 complications during the prevalence of most virulent strains, this study has generated a different way of understanding COVID-19 and its complications for better community health.

Antibody Response to the SARS-CoV-2 Spike and Nucleocapsid Proteins in Patients with Different COVID-19 Clinical Profiles

The first case of coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), in Brazil was diagnosed on February 26, 2020. Due to the important epidemiological impact of COVID-19, the present study aimed to analyze the specificity of IgG antibody responses to the S1, S2 and N proteins of SARS-CoV-2 in different COVID-19 clinical profiles. This study enrolled 136 individuals who were diagnosed with or without COVID-19 based on clinical findings and laboratory results and classified as asymptomatic or as having mild, moderate or severe disease. Data collection was performed through a semistructured questionnaire to obtain demographic information and main clinical manifestations. IgG antibody responses to the S1 and S2 subunits of the spike (S) protein and the nucleocapsid (N) protein were evaluated using an enzyme-linked immunosorbent assay (ELISA) according to the manufacturer’s instructions. The results showed that among the participants, 87.5% (119/136) exhibited IgG responses to the S1 subunit and 88.25% (120/136) to N. Conversely, only 14.44% of the subjects (21/136) displayed S2 subunit responses. When analyzing the IgG antibody response while considering the different proteins of the virus, patients with severe disease had significantly higher antibody responses to N and S1 than asymptomatic individuals (p ≤ 0.0001), whereas most of the participants had low antibody titers against the S2 subunit. In addition, individuals with long COVID-19 showed a greater IgG response profile than those with symptomatology of a short duration. Based on the results of this study, it is concluded that levels of IgG antibodies may be related to the clinical evolution of COVID-19, with high levels of IgG antibodies against S1 and N in severe cases and in individuals with long COVID-19.

Post-acute sequelae of COVID-19 is characterized by diminished peripheral CD8+β7 integrin+ T cells and anti-SARS-CoV-2 IgA response

Several millions of individuals are estimated to develop post-acute sequelae SARS-CoV-2 condition (PASC) that persists for months after infection. Here we evaluate the immune response in convalescent individuals with PASC compared to convalescent asymptomatic and uninfected participants, six months following their COVID-19 diagnosis. Both convalescent asymptomatic and PASC cases are characterised by higher CD8⁺ T cell percentages, however, the proportion of blood CD8⁺ T cells expressing the mucosal homing receptor β7 is low in PASC patients. CD8 T cells show increased expression of PD-1, perforin and granzyme B in PASC, and the plasma levels of type I and type III (mucosal) interferons are elevated. The humoral response is characterized by higher levels of IgA against the N and S viral proteins, particularly in those individuals who had severe acute disease. Our results also show that consistently elevated levels of IL-6, IL-8/CXCL8 and IP-10/CXCL10 during acute disease increase the risk to develop PASC. In summary, our study indicates that PASC is defined by persisting immunological dysfunction as late as six months following SARS-CoV-2 infection, including alterations in mucosal immune parameters, redistribution of mucosal CD8⁺β7Integrin⁺ T cells and IgA, indicative of potential viral persistence and mucosal involvement in the etiopathology of PASC.

Health progression for Covid-19 survivors hospitalized in geriatric clinics in Sweden

OBJECTIVE

To analyse if the health progression of geriatric Covid-19 survivors three months after an acute Covid-19 infection was worse than in other geriatric patients. Specifically, we wanted to see if we could see distinct health profiles in the flow of re-admitted Covid-19 patients compared to re-admitted non-Covid-19 controls.

DESIGN

Matched cohort study.

SETTING AND PARTICIPANTS

Electronic medical records of geriatric patients hospitalised in geriatric clinics in Stockholm, Sweden, between March 2020 and January 2022. Patients readmitted three months after initial admission were selected for the analysis and Covid-19 survivors (n = 895) were compared to age-sex-Charlson comorbidity index (CCI)-matched non-Covid-19 controls (n = 2685).

METHODS

We assessed using binary logistic and Cox regression if a previous Covid-19 infection could be a risk factor for worse health progression indicated by the CCI, hospital frailty risk score (HFRS), mortality and specific comorbidities.

RESULTS

The patients were mostly older than 75 years and, already at baseline, had typically multiple comorbidities. The Covid-19 patients with readmission had mostly had their acute-phase infection in the 1st or 2nd pandemic waves before the vaccinations. The Covid-19 patients did not have worse health after three months compared to the matched controls according to the CCI (odds ratio, OR[95% confidence interval, CI] = 1.12[0.94-1.34]), HFRS (OR[95%CI] = 1.05[0.87-1.26]), 6-months (hazard ratio, HR[95%CI] = 1.04[0.70-1.52]) and 1-year-mortality risk (HR[95%CI] = 0.89[0.71-1.10]), adjusted for age, sex and health at baseline (the CCI and HFRS).

CONCLUSIONS AND IMPLICATIONS

The overall health progression of re-hospitalized geriatric Covid-19 survivors did not differ dramatically from other re-hospitalized geriatric patients with similar age, sex and health at baseline. Our results emphasize that Covid-19 was especially detrimental for geriatric patients in the acute-phase, but not in the later phase. Further studies including post-vaccination samples are needed.

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

COVID-19, with persistent and new onset of symptoms such as fatigue, post-exertional malaise, and cognitive dysfunction that last for months and impact everyday functioning, is referred to as Long COVID under the general category of post-acute sequelae of SARS-CoV-2 infection (PASC). PASC is highly heterogenous and may be associated with multisystem tissue damage/dysfunction including acute encephalitis, cardiopulmonary syndromes, fibrosis, hepatobiliary damages, gastrointestinal dysregulation, myocardial infarction, neuromuscular syndromes, neuropsychiatric disorders, pulmonary damage, renal failure, stroke, and vascular endothelial dysregulation. A better understanding of the pathophysiologic mechanisms underlying PASC is essential to guide prevention and treatment. This review addresses potential mechanisms and hypotheses that connect SARS-CoV-2 infection to long-term health consequences. Comparisons between PASC and other virus-initiated chronic syndromes such as myalgic encephalomyelitis/chronic fatigue syndrome and postural orthostatic tachycardia syndrome will be addressed. Aligning symptoms with other chronic syndromes and identifying potentially regulated common underlining pathways may be necessary for understanding the true nature of PASC. The discussed contributors to PASC symptoms include sequelae from acute SARS-CoV-2 injury to one or more organs, persistent reservoirs of the replicating virus or its remnants in several tissues, re-activation of latent pathogens such as Epstein-Barr and herpes viruses in COVID-19 immune-dysregulated tissue environment, SARS-CoV-2 interactions with host microbiome/virome communities, clotting/coagulation dysregulation, dysfunctional brainstem/vagus nerve signaling, dysautonomia or autonomic dysfunction, ongoing activity of primed immune cells, and autoimmunity due to molecular mimicry between pathogen and host proteins. The individualized nature of PASC symptoms suggests that different therapeutic approaches may be required to best manage specific patients.

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

COVID-19, with persistent and new onset of symptoms such as fatigue, post-exertional malaise, and cognitive dysfunction that last for months and impact everyday functioning, is referred to as Long COVID under the general category of post-acute sequelae of SARS-CoV-2 infection (PASC). PASC is highly heterogenous and may be associated with multisystem tissue damage/dysfunction including acute encephalitis, cardiopulmonary syndromes, fibrosis, hepatobiliary damages, gastrointestinal dysregulation, myocardial infarction, neuromuscular syndromes, neuropsychiatric disorders, pulmonary damage, renal failure, stroke, and vascular endothelial dysregulation. A better understanding of the pathophysiologic mechanisms underlying PASC is essential to guide prevention and treatment. This review addresses potential mechanisms and hypotheses that connect SARS-CoV-2 infection to long-term health consequences. Comparisons between PASC and other virus-initiated chronic syndromes such as myalgic encephalomyelitis/chronic fatigue syndrome and postural orthostatic tachycardia syndrome will be addressed. Aligning symptoms with other chronic syndromes and identifying potentially regulated common underlining pathways may be necessary for understanding the true nature of PASC. The discussed contributors to PASC symptoms include sequelae from acute SARS-CoV-2 injury to one or more organs, persistent reservoirs of the replicating virus or its remnants in several tissues, re-activation of latent pathogens such as Epstein-Barr and herpes viruses in COVID-19 immune-dysregulated tissue environment, SARS-CoV-2 interactions with host microbiome/virome communities, clotting/coagulation dysregulation, dysfunctional brainstem/vagus nerve signaling, dysautonomia or autonomic dysfunction, ongoing activity of primed immune cells, and autoimmunity due to molecular mimicry between pathogen and host proteins. The individualized nature of PASC symptoms suggests that different therapeutic approaches may be required to best manage specific patients.

Severity and geographical disparities of post-COVID-19 symptoms among the Vietnamese general population: a national evaluation

Post-COVID-19 symptoms have become a significant global health concern. This study focused on assessing the prevalence, severity, and care preference of post-COVID-19 symptoms, as well as identifying determinants to inform evidence-based policy on post-COVID-19 in Vietnam. A national cross-sectional study was conducted in May 2022 among 12,361 recovered COVID-19 patients, providing the largest dataset on health status after COVID-19 in Vietnam. The study utilized ordered logistic, Poisson regression, Multilevel linear random-effects models, and Multilevel random effects ordered logistic model to identify factors associated with various aspects of post-COVID-19 conditions. Results showed that the average number of post-COVID-19 symptoms was approximately 3, with fatigue and headache being the most common symptoms. The number of post-COVID-19 symptoms varied by province, decreased with age, and was significantly correlated with the duration of infection. Age, infection period, underlying conditions, telehealth utilization, and geographical location were identified as significant determinants of post-COVID-19 symptoms. The study concluded that improving resource allocation and health-seeking behavior in underserved areas could help address differences in health outcomes and improve post-COVID-19 control in Vietnam.

Late Complications of COVID-19; An Umbrella Review on Current Systematic Reviews

Introduction

Several clinical manifestations have been discovered for COVID-19 since the emergence of SARS-CoV-2, which can be classified into early, medium, and long-term complications. However, late complications can be present after recovery from acute COVID-19 illness. The present study aims to comprehensively review the available evidence of late complications related to COVID-19.

Method

A search was conducted, using keywords, through electronic databases, which included Scopus, Web of Science, PubMed, and Embase up to August 29, 2022. Study selection was performed according to a strict inclusion and exclusion criteria. The Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) checklist was followed, and studies were appraised using the National Institute of Health (NIH) quality assessment and risk of bias tool.

Results

In total, 50 studies were included, and nine distinct COVID-19 late complication categories were identified. A review of these studies revealed that neurologic and psychiatric (n=41), respiratory (n=27), musculoskeletal and rheumatologic (n=22), cardiovascular (n=9), and hepatic and gastrointestinal (n=6) complications were the most prevalent complications of long COVID-19.

Conclusion

Almost all human body systems are affected by late complications of COVID-19 with different severity and prevalence. Fatigue and some other neuropsychiatric symptoms are the most common late complications among long COVID-19 patients. Respiratory symptoms including dyspnea (during exercise), cough, and chest tightness were the next most prevalent long-term complications of COVID-19. Since these complications are persistent and late, being aware of the signs and symptoms is essential for the healthcare providers and patients.

Persistent COVID-19 symptoms in community-living older adults from the Canadian Longitudinal Study on Aging (CLSA)

BACKGROUND

Symptom persistence in non-hospitalized COVID-19 patients, also known as Long COVID or Post-acute Sequelae of COVID-19, is not well characterized or understood, and few studies have included non-COVID-19 control groups.

METHODS

We used data from a cross-sectional COVID-19 questionnaire (September-December 2020) linked to baseline (2011-2015) and follow-up (2015-2018) data from a population-based cohort including 23,757 adults 50+ years to examine how age, sex, and pre-pandemic physical, psychological, social, and functional health were related to the severity and persistence of 23 COVID-19-related symptoms experienced between March 2020 and questionnaire completion.

RESULTS

The most common symptoms are fatigue, dry cough, muscle/joint pain, sore throat, headache, and runny nose; reported by over 25% of participant who had (n = 121) or did not have (n = 23,636) COVID-19 during the study period. The cumulative incidence of moderate/severe symptoms in people with COVID-19 is more than double that reported by people without COVID-19, with the absolute difference ranging from 16.8% (runny nose) to 37.8% (fatigue). Approximately 60% of male and 73% of female participants with COVID-19 report at least one symptom persisting >1 month. Persistence >1 month is higher in females (aIRR = 1.68; 95% CI: 1.03, 2.73) and those with multimorbidity (aIRR = 1.90; 95% CI: 1.02, 3.49); persistence >3 months decreases by 15% with each unit increase in subjective social status after adjusting for age, sex and multimorbidity.

CONCLUSIONS

Many people living in the community who were not hospitalized for COVID-19 still experience symptoms 1- and 3-months post infection. These data suggest that additional supports, for example access to rehabilitative care, are needed to help some individuals fully recover.

Impact of Unexpected In-House Major COVID-19 Outbreaks on Depressive Symptoms among Healthcare Workers: A Retrospective Multi-Institutional Study

The coronavirus disease 2019 (COVID-19) has significantly affected the mental health of healthcare workers (HCWs). The authors have provided psychosocial support to HCWs working in typical hospitals and nursing homes in Fukushima Prefecture, Japan, where major COVID-19 outbreaks have occurred since December 2020. This study retrospectively examines depressive symptoms before psychosocial interventions among HCWs working at typical hospitals and nursing homes experiencing in-house major COVID-19 outbreaks. We have offered psychosocial support in eight hospitals and nursing homes, obtaining data on the mental health status of 558 HCWs using the Patient Health Questionnaire-9. The study's results indicate that 29.4% of HCWs have exhibited moderate or higher depressive symptoms, and 10.2% had suicidal ideation. Multiple logistic regression analysis showed that being a nurse was associated with higher depressive symptoms and suicidal ideation compared to other HCWs. In addition, multiple logistic regression analysis of Polymerase Chain Reaction-positive HCWs showed that being a nurse and the number of COVID-19-related symptoms was associated with high depressive symptoms. These results suggest that HCWs in typical hospitals and nursing homes experiencing major COVID-19 outbreaks are more likely to exhibit severe depressive symptoms, which may worsen if infected with COVID-19. This study's findings expand the current understanding of HCWs' depressive symptoms and the importance of psychosocial support during unexpected major outbreaks in healthcare facilities.

Towards a Better Understanding of the Complexities of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Long COVID

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a complex condition arising in susceptible people, predominantly following viral infection, but also other stressful events. The susceptibility factors discussed here are both genetic and environmental although not well understood. While the dysfunctional physiology in ME/CFS is becoming clearer, understanding has been hampered by different combinations of symptoms in each affected person. A common core set of mainly neurological symptoms forms the modern clinical case definition, in the absence of an accessible molecular diagnostic test. This landscape has prompted interest in whether ME/CFS patients can be classified into a particular phenotype/subtype that might assist better management of their illness and suggest preferred therapeutic options. Currently, the same promising drugs, nutraceuticals, or behavioral therapies available can be beneficial, have no effect, or be detrimental to each individual patient. We have shown that individuals with the same disease profile exhibit unique molecular changes and physiological responses to stress, exercise and even vaccination. Key features of ME/CFS discussed here are the possible mechanisms determining the shift of an immune/inflammatory response from transient to chronic in ME/CFS, and how the brain and CNS manifests the neurological symptoms, likely with activation of its specific immune system and resulting neuroinflammation. The many cases of the post viral ME/CFS-like condition, Long COVID, following SARS-CoV-2 infection, and the intense research interest and investment in understanding this condition, provide exciting opportunities for the development of new therapeutics that will benefit ME/CFS patients.

Approach to post COVID-19 persistent cough: A narrative review

A large proportion of patients who completely recovered from acute coronavirus disease 2019 (COVID-19) infection later continued to experience symptoms even after recovery, irrespective of the severity of the disease. Various terms with varying duration were used for those who had persistent symptoms, of which cough was the most common. We systematically searched the published literature concerning post-COVID-19 cough, its prevalence, and the potential ways to reduce it in clinical practice. The aim of this review was to provide an overview of existing literature concerning post-COVID-19 cough. Literature shows that augmented cough reflex sensitivity is responsible for persistent cough after acute viral upper respiratory infection (URI). Overall, the heightened cough reflex associated with SARSCoV2 induces neurotropism, neuroinflammation, and neuroimmunomodulation via the vagal sensory nerves. Therapies for post-COVID-19 cough aim at the suppression of cough reflex. For a patient who does not respond to early symptomatic treatment, Inhaled corticosteroids can be given a trial to suppress airway inflammation. More trials of novel cough therapies in patients with post-COVID-19 cough using various outcome measures need to be studied in future research. Several agents are currently available for symptomatic relief. However, non-response or refractory cough continues to preclude adequate symptom relief.

A cohort study of post-COVID-19 condition across the Beta, Delta, and Omicron waves in South Africa: 6-month follow-up of hospitalized and nonhospitalized participants

OBJECTIVES

The study aimed to describe the prevalence of and risk factors for post-COVID-19 condition (PCC).

METHODS

This was a prospective, longitudinal observational cohort study. Hospitalized and nonhospitalized adults were randomly selected to undergo telephone assessment at 1, 3, and 6 months. Participants were assessed using a standardized questionnaire for the evaluation of symptoms and health-related quality of life. We used negative binomial regression models to determine factors associated with the presence of ≥1 symptoms at 6 months.

RESULTS

A total of 46.7% of hospitalized and 18.5% of nonhospitalized participants experienced ≥1 symptoms at 6 months (P ≤0.001). Among hospitalized people living with HIV, 40.4% had persistent symptoms compared with 47.1% among participants without HIV (P = 0.108). The risk factors for PCC included older age, female sex, non-Black race, presence of a comorbidity, greater number of acute COVID-19 symptoms, hospitalization/COVID-19 severity, and wave period (lower risk of persistent symptoms for the Omicron compared with the Beta wave). There were no associations between self-reported vaccination status with persistent symptoms.

CONCLUSION

The study revealed a high prevalence of persistent symptoms among South African participants at 6 months but decreased risk for PCC among participants infected during the Omicron BA.1 wave. These findings have serious implications for countries with resource-constrained health care systems.

Conceptualising the episodic nature of disability among adults living with Long COVID: a qualitative study

INTRODUCTION

Our aim was to describe episodic nature of disability among adults living with Long COVID.

METHODS

We conducted a community-engaged qualitative descriptive study involving online semistructured interviews and participant visual illustrations. We recruited participants via collaborator community organisations in Canada, Ireland, UK and USA.We recruited adults who self-identified as living with Long COVID with diversity in age, gender, race/ethnicity, sexual orientation and duration since initial COVID infection between December 2021 and May 2022. We used a semistructured interview guide to explore experiences of disability living with Long COVID, specifically health-related challenges and how they were experienced over time. We asked participants to draw their health trajectory and conducted a group-based content analysis.

RESULTS

Among the 40 participants, the median age was 39 years (IQR: 32-49); majority were women (63%), white (73%), heterosexual (75%) and living with Long COVID for ≥1 year (83%). Participants described their disability experiences as episodic in nature, characterised by fluctuations in presence and severity of health-related challenges (disability) that may occur both within a day and over the long-term living with Long COVID. They described living with 'ups and downs', 'flare-ups' and 'peaks' followed by 'crashes', 'troughs' and 'valleys', likened to a 'yo-yo', 'rolling hills' and 'rollercoaster ride' with 'relapsing/remitting', 'waxing/waning', 'fluctuations' in health. Drawn illustrations demonstrated variety of trajectories across health dimensions, some more episodic than others. Uncertainty intersected with the episodic nature of disability, characterised as unpredictability of episodes, their length, severity and triggers, and process of long-term trajectory, which had implications on broader health.

CONCLUSION

Among this sample of adults living with Long COVID, experiences of disability were described as episodic, characterised by fluctuating health challenges, which may be unpredictable in nature. Results can help to better understand experiences of disability among adults living with Long COVID to inform healthcare and rehabilitation.

Longitudinal medical subspecialty follow-up of critically and non-critically ill hospitalized COVID-19 survivors up to 24 months after discharge

Medical specialty usage of COVID-19 survivors after hospital discharge is poorly understood. This study investigated medical specialty usage at 1-12 and 13-24 months post-hospital discharge in critically ill and non-critically ill COVID-19 survivors. This retrospective study followed ICU (N = 89) and non-ICU (N = 205) COVID-19 survivors who returned for follow-up within the Stony Brook Health System post-hospital discharge. Follow-up data including survival, hospital readmission, ongoing symptoms, medical specialty care use, and ICU status were examined 1-12 and 13-24 months after COVID-19 discharge. "New" (not previously seen) medical specialty usage was also identified. Essentially all (98%) patients survived. Hospital readmission was 34%, but functional status scores at discharge were not associated with hospital readmission. Many patients reported ongoing [neuromuscular (50%) respiratory (39%), chronic fatigue (35%), cardiovascular (30%), gastrointestinal (28%), neurocognitive (22%), genitourinary (22%), and mood-related (13%)] symptoms at least once 1-24 months after discharge. Common specialty follow-ups included cardiology (25%), vascular medicine (17%), urology (17%), neurology (16%), and pulmonology (14%), with some associated with pre-existing comorbidities and with COVID-19. Common new specialty visits were vascular medicine (11%), pulmonology (11%), and neurology (9%). ICU patients had more symptoms and follow-ups compared to the non-ICU patients. This study reported high incidence of persistent symptoms and medical specialty care needs in hospitalized COVID-19 survivors 1-24 months post-discharge. Some specialty care needs were COVID-19 related or exacerbated by COVID-19 disease while others were associated with pre-existing medical conditions. Longer follow-up studies of COVID-19 survivor medical care needs are necessary.

Pooled Prevalence of Long COVID-19 Symptoms at 12 Months and Above Follow-Up Period: A Systematic Review and Meta-Analysis

Current data suggests that coronavirus disease 2019 (COVID-19) survivors experience long-lasting problems. It is not yet understood how long these symptoms last. The goal of this study was to compile all the data that was currently available to evaluate COVID-19's long-term effects at 12 months and above. We looked for studies published by December 15, 2022, in PubMed and Embase that discussed follow-up findings for COVID-19 survivors who had been alive for at least a year. A random-effect model was carried out to determine the combined prevalence of different long-COVID symptoms. The Joanna Briggs Institute tool was used to assess the risk of bias for the included studies, and the I2 statistics were used to evaluate the heterogeneity. After reviewing 3,209 studies, 46 were deemed admissible, with an aggregate COVID-19 population of 17976. At 12 months and above, 57% of patients reported a minimum of one symptom, and the five most prevalent symptoms were: dyspnea on exertion (34%, 95% CI 0.2; 0.94); difficulty in concentration (32%, 95% CI 0.16; 0.52); fatigue (31%, 95% CI 0.22; 0.40); frailty (31%, 95% CI 0.06; 0.78); and arthromyalgia (28%, 95% CI 0.09; 0.6). The findings of the present study showed that at 12 months and beyond, a sizable fraction of COVID-19 survivors still have lasting symptoms that impair several body systems. Long-COVID patients require an urgent understanding of pathophysiological processes and the development of tailored treatments.