Gastrointestinal manifestations of long COVID: A systematic review and meta-analysis

Long COVID in Children, Adults, and Vulnerable Populations: A Comprehensive Overview for an Integrated Approach

Long COVID affects both children and adults, including subjects who experienced severe, mild, or even asymptomatic SARS-CoV-2 infection. We have provided a comprehensive overview of the incidence, clinical characteristics, risk factors, and outcomes of persistent COVID-19 symptoms in both children and adults, encompassing vulnerable populations, such as pregnant women and oncological patients. Our objective is to emphasize the critical significance of adopting an integrated approach for the early detection and appropriate management of long COVID. The incidence and severity of long COVID symptoms can have a significant impact on the quality of life of patients and the course of disease in the case of pre-existing pathologies. Particularly, in fragile and vulnerable patients, the presence of PASC is related to significantly worse survival, independent from pre-existing vulnerabilities and treatment. It is important try to achieve an early recognition and management. Various mechanisms are implicated, resulting in a wide range of clinical presentations. Understanding the specific mechanisms and risk factors involved in long COVID is crucial for tailoring effective interventions and support strategies. Management approaches involve comprehensive biopsychosocial assessments and treatment of symptoms and comorbidities, such as autonomic dysfunction, as well as multidisciplinary rehabilitation. The overall course of long COVID is one of gradual improvement, with recovery observed in the majority, though not all, of patients. As the research on long-COVID continues to evolve, ongoing studies are likely to shed more light on the intricate relationship between chronic diseases, such as oncological status, cardiovascular diseases, psychiatric disorders, and the persistent effects of SARS-CoV-2 infection. This information could guide healthcare providers, researchers, and policymakers in developing targeted interventions.

Long-Term effects of COVID-19: a review of current perspectives and mechanistic insights

Although SARS-CoV-2, responsible for COVID-19, is primarily a respiratory infection, a broad spectrum of cardiac, pulmonary, neurologic, and metabolic complications can occur. More than 50 long-term symptoms of COVID-19 have been described, and as many as 80% of patients may develop ≥1 long-term symptom. To summarize current perspectives of long-term sequelae of COVID-19, we conducted a PubMed search describing the long-term cardiovascular, pulmonary, gastrointestinal, and neurologic effects post-SARS-CoV-2 infection and mechanistic insights and risk factors for the above-mentioned sequelae. Emerging risk factors of long-term sequelae include older age (≥65 years), female sex, Black or Asian race, Hispanic ethnicity, and presence of comorbidities. There is an urgent need to better understand ongoing effects of COVID-19. Prospective studies evaluating long-term effects of COVID-19 in all body systems and patient groups will facilitate appropriate management and assess burden of care. Clinicians should ensure patients are followed up and managed appropriately, especially those in at-risk groups. Healthcare systems worldwide need to develop approaches to follow-up and support patients recovering from COVID-19. Surveillance programs can enhance prevention and treatment efforts for those most vulnerable.

The Aftermath of COVID-19: Exploring the Long-Term Effects on Organ Systems

BACKGROUND

Post-acute sequelae of SARS-CoV-2 infection (PASC) is a complicated disease that affects millions of people all over the world. Previous studies have shown that PASC impacts 10% of SARS-CoV-2 infected patients of which 50-70% are hospitalised. It has also been shown that 10-12% of those vaccinated against COVID-19 were affected by PASC and its complications. The severity and the later development of PASC symptoms are positively associated with the early intensity of the infection.

RESULTS

The generated health complications caused by PASC involve a vast variety of organ systems. Patients affected by PASC have been diagnosed with neuropsychiatric and neurological symptoms. The cardiovascular system also has been involved and several diseases such as myocarditis, pericarditis, and coronary artery diseases were reported. Chronic hematological problems such as thrombotic endothelialitis and hypercoagulability were described as conditions that could increase the risk of clotting disorders and coagulopathy in PASC patients. Chest pain, breathlessness, and cough in PASC patients were associated with the respiratory system in long-COVID causing respiratory distress syndrome. The observed immune complications were notable, involving several diseases. The renal system also was impacted, which resulted in raising the risk of diseases such as thrombotic issues, fibrosis, and sepsis. Endocrine gland malfunction can lead to diabetes, thyroiditis, and male infertility. Symptoms such as diarrhea, nausea, loss of appetite, and taste were also among reported observations due to several gastrointestinal disorders. Skin abnormalities might be an indication of infection and long-term implications such as persistent cutaneous complaints linked to PASC.

CONCLUSIONS

Long-COVID is a multidimensional syndrome with considerable public health implications, affecting several physiological systems and demanding thorough medical therapy, and more study to address its underlying causes and long-term effects is needed.

Gastrointestinal Manifestations and Their Association with Neurologic and Sleep Problems in Long COVID-19 Minority Patients: A Prospective Follow-Up Study

BACKGROUND

Long-COVID is a condition post SARS-CoV-2 infection with persistent or recurring symptoms affecting multiple organs, and may involve viral persistence, changes to the microbiome, coagulopathies, and alterations to neuro-immune interactions. These factors can disrupt the Gut-Brain Axis, which is a complex system involving bidirectional communication between the central nervous system and the gastrointestinal (GI) system. As a result of these disruptions, individuals with long-COVID may develop post-infectious functional GI disorders, which can cause a range of symptoms affecting the digestive system.

AIM

To understand frequency of GI manifestations of Long-COVID and to determine association with sleep or neurological symptoms in a predominantly minority population.

METHODS

We included patients with positive SARS-CoV-2 PCR (n = 747) who were hospitalized from Feb. 2020 to May 2021 at Howard University Hospital and followed between 6 and 12 months from discharge. GI, sleep, and neurological symptoms (via the Montreal Cognitive Assessment (MoCA) scoring system) were assessed using a standardized questionnaire. Linear regression analysis, χ2 and Fisher's exact test were utilized to determine the statistical significance of correlations of GI/Neuro/COVID.

RESULTS

The mean age of patients was 58, with 51.6% females and a predominant African American ethnicity (73.6%, n = 550). A total of 108 patients died during their initial hospital stay, with the remaining 639 patients followed-up. Three hundred fifty (350) patients responded to the questionnaire (57 patients died during the follow-up period). Overall, 39 (13.3%) patients reported GI-related symptoms, out of which 19 (6.4%) had persistent symptoms and 20 (6.8%) developed new onset GI symptoms. Nausea and vomiting were the most common 24/39 (61.5%), followed by abdominal pain 7/39 (18%), diarrhea 5/39 (12.8%), and others 3/39 (7.6%). Patients who presented with vomiting during acute SARS-CoV-2 infection were more likely to have Long-COVID GI manifestations (P = 0.023). Use of ACE inhibitors, abnormal lymphocyte count and elevated ferritin are other variables that showed significant associations with Long-COVID GI manifestations (P = 0.03, 0.006 and 0.03, respectively). During follow-up, a total of 28 (9.5%) patients reported difficulty with sleep and 79 (27%) patients had abnormal MoCA assessment. With further analysis, there was a trend between presentation of GI symptoms on admission with abnormal MoCA assessment, and an association between abnormal LFTs and history of liver disease during hospitalization with subsequent sleep problems. Baseline characteristics, clinical comorbidities, other laboratory values, hospital length of stay, mechanical ventilation, medications during hospitalization, re-admission and Flu or COVID-19 vaccination have not shown any association with Long-COVID GI symptoms in our cohort.

CONCLUSION

Dyspeptic symptoms were common GI manifestations in the acute and post COVID periods. GI symptoms, abnormal LFTs and a history of liver disease during the acute infectious phase associates with abnormal MoCA and sleep problems during follow-up. Further large population studies are needed to determine if COVID-19 leads to a GI symptoms-associated Long-COVID phenotypes and other symptoms through the Gut-Brain-Axis.

The incidence and predisposing factors for irritable bowel syndrome following COVID-19: a systematic review and meta-analysis

BACKGROUND

Irritable bowel syndrome (IBS) is a common functional gastrointestinal (GI) disorder. Several studies have analyzed the long-term GI symptoms and IBS following coronavirus disease 2019 (COVID-19). The purpose of this study is to evaluate the incidence and predisposing factors for IBS following COVID-19 by a systematic review and meta-analysis.

METHODS

Electronic databases were searched to identify relevant studies. Primary outcomes were the pooled incidence rate of IBS following COVID-19 and the pooled relative risk (RR) for IBS in the COVID-19 group compared to the non-COVID-19 group. Secondary outcomes were the pooled RR and the standardized mean difference (SMD) for predisposing factors in the IBS group compared to the non-IBS group. Heterogeneity was evaluated using Cochran's Q test and I2 statistics.

RESULTS

Ten studies were included in this study. The pooled incidence rate of IBS in COVID-19 patients was 12%. The pooled incidence rate of IBS-D, IBS-C and IBS-M was 5%, 2% and 1%. The pooled incidence rate of IBS in 6 and 12 months was 10% and 3%. The pooled RR for IBS in COVID-19 patients was 1.23 [95% confidence interval (CI) = 0.50-3.01] compared to non-COVID-19 patients. The pooled RR or SMD for mild, moderate, and severe disease activity, procalcitonin (PCT), depression or anxiety in IBS patients following COVID-19 was 0.94 (95% CI = 0.74-1.21), 1.19 (95% CI = 0.65-2.21), 1.30 (95% CI = 0.63-2.66), 6.73 (95% CI = 6.08-7.38) and 3.21 (95% CI = 1.79-5.75).

CONCLUSION

The incidence of IBS following COVID-19 was 12%. But it was not higher than the general population. We also found some predisposing factors for IBS including depression or anxiety, PCT.

Role of dietary supplements in the continuous battle against COVID-19

A sudden outbreak of the COVID-19 pandemic was a big blow to the world community on every level. Created by a novel coronavirus, SARS-CoV-2, which was previously unknown to the human immune system. The expert opinion almost immediately united on the fact that the most effective way of fighting the pandemic would be by building immunity artificially via a mass immunization program. However, it took about a year for the approval of the first vaccine against COVID-19. In the meantime, a big part of the general population started adapting nutritious diet plans and dietary supplements to boost natural immunity as a potential prophylactic strategy against SARS-CoV-2 infection. Whether they originate from mainstream medicine, such as synthetic supplements, or traditional herbal remedies in the form of single or poly-herbs, these supplements may comprise various components that exhibit immunomodulatory, anti-inflammatory, antioxidant, and antimicrobial characteristics. There is a substantial body of predictions and expert opinions suggesting that enhancing one's diet with dietary supplements containing additional nutrients and bioactive compounds like vitamins, minerals, amino acids, fatty acids, phytochemicals, and probiotics can enhance the immune system's ability to develop resistance against COVID-19, although none of them have any conclusive evidence nor officially recommended by World Health Organization (WHO). The current review critically acclaims the gap between public perception-based preference and real evidence-based study to weigh the actual benefit of dietary supplements in relation to COVID-19 prevention and management.

The Multisystem Impact of Long COVID: A Comprehensive Review

(1) Background: COVID-19 was responsible for the latest pandemic, shaking and reshaping healthcare systems worldwide. Its late clinical manifestations make it linger in medical memory as a debilitating illness over extended periods. (2) Methods: the recent literature was systematically analyzed to categorize and examine the symptomatology and pathophysiology of Long COVID across various bodily systems, including pulmonary, cardiovascular, gastrointestinal, neuropsychiatric, dermatological, renal, hematological, and endocrinological aspects. (3) Results: The review outlines the diverse clinical manifestations of Long COVID across multiple systems, emphasizing its complexity and challenges in diagnosis and treatment. Factors such as pre-existing conditions, initial COVID-19 severity, vaccination status, gender, and age were identified as influential in the manifestation and persistence of Long COVID symptoms. This condition is highlighted as a debilitating disease capable of enduring over an extended period and presenting new symptoms over time. (4) Conclusions: Long COVID emerges as a condition with intricate multi-systemic involvement, complicating its diagnosis and treatment. The findings underscore the necessity for a nuanced understanding of its diverse manifestations to effectively manage and address the evolving nature of this condition over time.

Post-infection irritable bowel syndrome following Coronavirus disease-19: A systematic review and meta-analysis

BACKGROUND AND OBJECTIVES: Persistent gastrointestinal (GI) symptoms and functional gastrointestinal disorders (FGIDs) are increasingly being recognized after Coronavirus disease-19 (COVID-19). Though quite a few studies addressed irritable bowel syndrome (IBS) following COVID-19, the disorders' prevalence varies greatly. We evaluated, (i) overall frequency of post-COVID-19 IBS, (ii) relative risk of development of IBS among COVID-19 patients compared to healthy controls using systematic review and meta-analysis techniques.

METHODS

Literature search was performed for studies on GI symptoms and FGIDs after COVID-19 using electronic databases (Medline, Scopus, Cochrane Central Register of Controlled Trials, Google Scholar and Web of Science) till April 28, 2023. We included studies reporting IBS after COVID-19 with any duration of follow-up and any number of subjects. Studies on pediatric population and those not providing relevant information were excluded. Relative risk of development of IBS using Rome criteria among COVID-19 patients compared to healthy controls was calculated. Analysis was done using MedCalc (Applied Math, Mariakerke, Belgium, version 7.2) and Comprehensive Meta-Analysis version 3.3.070 (Biostat Inc. Englewood, NJ 07631, USA).

RESULTS

Of the available studies, 13 (four case-control) reporting on IBS after COVID-19 met inclusion criteria. Among 3950 COVID-19 patients and 991 controls, 7.2% of COVID-19 patients and 4.9% of healthy controls developed IBS. Of the four case-control studies reporting post-COVID-19 IBS, patients with COVID-19 were 2.65 (95% confidence interval [CI] 0.538 to 13.039) times more likely to have post-COVID-19 IBS as compared to healthy controls.

CONCLUSIONS

Patients with COVID-19 are more likely to develop post-COVID-19 IBS than healthy controls. The heterogeneity of studies, different criteria used by various studies to diagnose post-COVID-19 IBS and some studies not meeting the six-month follow-up duration of the Rome criteria for diagnosing IBS are limitations of this systematic review.

Association of gut microbiota with the pathogenesis of SARS-CoV-2 Infection in people living with HIV

BACKGROUND

People living with HIV (PLWH) with chronic inflammation may have an increasing risk for coronavirus disease 2019 (COVID-19) severity; however, the impact of their gut microbiota on COVID-19 is not fully elucidated. Here, we analyzed the temporal changes in the gut microbiota composition of hospitalized severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected PLWH (PLWH-CoV) and their correlation with COVID-19 severity.

RESULT

The 16S rRNA analysis results using stool samples (along the timeline from disease onset) from 12 hospitalized PLWH-CoV, whose median CD4 + T cell count was 671 cells/µl, were compared to those of 19 healthy people and 25 PLWH. Bacterial diversity in PLWH-CoV is not significantly different from that of healthy people and SARS-CoV-2 non-infected PLWH, but a significant difference in the microbiota diversity was observed in the classification according to the disease severity. Immediately after the disease onset, remarkable changes were observed in the gut microbiota of PLWH-CoV, and the changing with a decrease in some short-chain fatty acid-producing bacteria and an increase in colitis-related pathobiont. In the second week after disease onset, relative amounts of specific bacteria distinguished between disease severity. One month after the disease onset, dysbiosis of the gut microbiota persisted, and the number of Enterobacteriaceae, mainly Escherichia-Shigella, which is potentially pathogenic, increased and were enriched in patients who developed post-acute sequelae of COVID-19 (PASC).

CONCLUSION

The changes in the gut microbiota associated with SARS-CoV-2 infection observed in PLWH in this study indicated a persistent decrease in SCFA-producing bacteria and an intestinal environment with an increase in opportunistic pathogens associated with enteritis. This report demonstrates that the intestinal environment in PLWH tends to show delayed improvement even after COVID-19 recovery, and highlights the importance of the dysbiosis associated with SARS-CoV-2 infection as a potential factor in the COVID-19 severity and the PASC in PLWH.

Clinical features of Japanese patients with gastrointestinal long-COVID symptoms

Gastrointestinal (GI) long-COVID symptoms, including diarrhea and abdominal pain, have been reported in patients with long-COVID. However, the clinical features of patients with GI long-COVID symptoms remain unclear. We conducted a large-scale prospective cohort study focusing on the clinical characteristics of patients with GI long-COVID symptoms in Japan. Among 943 COVID-19 patients, 58 patients (6.2%) had GI long-COVID symptoms. The health-related quality of life (QOL) parameters (the Short Form-8 [SF-8] and Euro Quality of Life 5 Dimensions 5 level [EQ-5D-5L]) at 12 months after diagnosis in patients with GI long-COVID symptoms were significantly lower than in those without GI long-COVID symptoms (P < 0.0001). Moreover, patients with GI long-COVID symptoms had more varied long-COVID symptoms compared to patients without GI long-COVID symptoms.

Post-COVID-19 and Irritable Bowel Syndrome: A Literature Review

The emergence of post-COVID-19 syndrome (PCS), a complex and multifactorial condition that follows the acute COVID-19 infection, has raised serious concerns within the global medical community. Concurrently, Irritable Bowel Syndrome (IBS), a widespread chronic gastrointestinal (GI) dysfunction, is considered to be one of the most common disorders of gut-brain interaction (DGBI) that significantly affects the quality of life and social functioning of patients. PCS presents a wide range of symptoms and GI manifestations, including IBS. This review aims to analyze the GI involvement and the prolonged symptoms of COVID-19 infection as part of PCS, in order to explore the potential development of post-infection IBS (PI-IBS) in COVID-19 patients. Irritating factors such as enteric infection, psychosocial conditions, food antigens, and antibiotics may lead to abnormalities in the physiological function of the GI system and could be involved in the development of PI-IBS. Through the presentation of the pathophysiological mechanisms and epidemiological studies that assessed the prevalence of IBS as part of PCS, we attempted to provide a better understanding of the long-term consequences of COVID-19 and the pathogenesis of PI-IBS. Even though PI-IBS is becoming a global challenge, there are only a few studies about it and therefore limited knowledge. Currently, the majority of the existing treatment options are referred to non-COVID-19-associated DGBIs. Forthcoming studies may shed light on the mechanisms of PI-IBS that could be targeted for treatment development.

Treatable traits for long COVID

Long COVID, or post-acute COVID-19 sequelae, is experienced by an estimated one in eight adults following acute COVID-19. Long COVID is a new and complex chronic health condition that typically includes multiple symptoms that cross organ systems and fluctuate over time; a one-size-fits-all approach is, therefore, not likely to be appropriate nor relevant for long COVID treatment. 'Treatable Traits' is a personalized medicine approach, purpose-built to address the complexity and heterogeneity of complex chronic conditions. This comprehensive review aimed to understand how a treatable traits approach could be applied to long COVID, by first identifying the most prevalent long COVID treatable traits and then the available evidence for strategies to target these traits. An umbrella review of 22 systematic reviews identified 34 symptoms and complications common with long COVID, grouped into eight long COVID treatable trait clusters: neurological, chest, psychological, pain, fatigue, sleep impairment, functional impairment and other. A systematic review of randomized control trials identified 18 studies that explored different intervention approaches for long COVID prevention (k = 4) or management (k = 14). While a single study reported metformin as effective for long COVID prevention, the findings need to be replicated and consensus is required around how to define long COVID as a clinical trial endpoint. For long COVID management, current evidence supports exercise training or respiratory muscle training for long COVID treatable traits in the chest and functional limitation clusters. While there are studies exploring interventions targeting other long COVID treatable traits, further high-quality RCTs are needed, particularly targeting treatable traits in the clusters of fatigue, psychological, pain and sleep impairment.

Long COVID Symptoms in Non-Hospitalised Patients: A Retrospective Study

INTRODUCTION

The COVID-19 pandemic has presented numerous challenges to healthcare systems. As the number of affected individuals continues to rise, it is crucial to find preventive, diagnostic, and therapeutic approaches. This study aims to describe different COVID-19 sequelae within a Primary Health Care population.

METHODS

A retrospective cohort study was conducted in adults diagnosed with COVID-19 from March 2020 to April 2022, excluding pregnant women, minors, nursing home residents, hospitalizations, and deaths. Data was gathered from surveillance records on the Trace COVID-19® platform, a pre-set original questionnaire (which included the Portuguese version of the World Health Organization's Quality of Life Assessment Instrument), and, if needed, patient electronic health records. Information on sociodemographic and clinical characteristics of acute COVID-19 was collected along with long COVID symptoms.

RESULTS

This study included 284 patients, aged 19 to 99 years old. The five most prevalent acute COVID-19 symptoms were fever (50.0%), tiredness (48.2%), myalgias (44.7%), dry cough (37.7%) and odynophagia (36.3%). Symptoms related to the neurological system (23.2%) and tiredness (22.9%) were the most prevalent in long COVID symptoms. Acute tiredness and arthralgia were associated with all long COVID outcomes. The associations between acute COVID-19 symptoms with long COVID outcomes were stronger for anosmia [OR = 5.07, 95% confidence interval (CI) 2.49 - 10.36, p < 0.001] on a neurological chapter, acute tiredness for long lasting tiredness (OR = 4.07, 95% CI 2.07 - 8.02, p = 0.041), fatigue for muscles and/or bones chapter (OR = 7.55, 95% CI 3.06 - 18.66, p < 0.001), tiredness on an endocrine/hormonal chapter (OR = 6.54, 95% CI 2.37 - 18.04, p < 0.001), dyspnea for respiratory symptoms (OR = 5.67, 95% CI 1.92 - 16.74, p = 0.002) and fever for stomach or intestine symptoms (OR = 8.06, 95% CI 2.55 - 25.47, p < 0.001). Almost all quality of life dimensions were negatively associated with the number of long COVID symptoms.

CONCLUSION

A higher number of acute symptoms, as well as the presence of specific COVID-19 symptoms were associated with reported symptoms ≥ 12 weeks after infection. In the studied population, an increased number of symptoms in both acute and long COVID had a significant negative impact on the perception of overall quality of life. The identification of these relationships could provide a new perspective for post-COVID care.

Epidemiology, clinical presentation, pathophysiology, and management of long COVID: an update

The increasing number of coronavirus disease 2019 (COVID-19) infections have highlighted the long-term consequences of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection called long COVID. Although the concept and definition of long COVID are described differently across countries and institutions, there is general agreement that it affects multiple systems, including the immune, respiratory, cardiovascular, gastrointestinal, neuropsychological, musculoskeletal, and other systems. This review aims to provide a synthesis of published epidemiology, symptoms, and risk factors of long COVID. We also summarize potential pathophysiological mechanisms and biomarkers for precise prevention, early diagnosis, and accurate treatment of long COVID. Furthermore, we suggest evidence-based guidelines for the comprehensive evaluation and management of long COVID, involving treatment, health systems, health finance, public attitudes, and international cooperation, which is proposed to improve the treatment strategies, preventive measures, and public health policy making of long COVID.

The new normal: a review of the impact of COVID-19 on gastroenterology fellowship training

The COVID-19 pandemic had a significant impact on medical education and gastroenterology fellowship training. As a result of the pandemic, a trainee's physical safety, mental health and wellness, clinical and procedural training, and educational opportunities were all potentially altered. Changes necessitated at the start of the pandemic were different than those needed further along in the pandemic course. Fellowship programs were required to modify policies and adapt to changes rapidly to advocate for their trainees and ensure quality education. Much of COVID-19's initial impact on education - decreased endoscopic procedures and the loss of educational conferences - has largely returned to pre-pandemic form. However, other changes made during the pandemic have persisted and likely will continue in the future. This includes a virtual interview format for fellowship matches, a virtual option for many national conferences, and an expansion of simulation training. This article reviews the impact that COVID-19 had on medical education with a specific focus on gastroenterology fellowship. The paper highlights the initial impact of COVID-19, the lingering effects, and discusses the areas needed for further research to best understand the total impact COVID-19 had on our trainees' education.

Gut-brain pathogenesis of post-acute COVID-19 neurocognitive symptoms

Approximately one third of non-hospitalized coronavirus disease of 2019 (COVID-19) patients report chronic symptoms after recovering from the acute stage of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Some of the most persistent and common complaints of this post-acute COVID-19 syndrome (PACS) are cognitive in nature, described subjectively as "brain fog" and also objectively measured as deficits in executive function, working memory, attention, and processing speed. The mechanisms of these chronic cognitive sequelae are currently not understood. SARS-CoV-2 inflicts damage to cerebral blood vessels and the intestinal wall by binding to angiotensin-converting enzyme 2 (ACE2) receptors and also by evoking production of high levels of systemic cytokines, compromising the brain's neurovascular unit, degrading the intestinal barrier, and potentially increasing the permeability of both to harmful substances. Such substances are hypothesized to be produced in the gut by pathogenic microbiota that, given the profound effects COVID-19 has on the gastrointestinal system, may fourish as a result of intestinal post-COVID-19 dysbiosis. COVID-19 may therefore create a scenario in which neurotoxic and neuroinflammatory substances readily proliferate from the gut lumen and encounter a weakened neurovascular unit, gaining access to the brain and subsequently producing cognitive deficits. Here, we review this proposed PACS pathogenesis along the gut-brain axis, while also identifying specific methodologies that are currently available to experimentally measure each individual component of the model.

The use of complementary and alternative medicine for the treatment of gastrointestinal symptoms in Long COVID: a systematic review

Background

Most people with coronavirus disease 2019 (COVID-19) experience resolution of symptoms within days to weeks following initial infection. In a subset of individuals, symptoms persist longer than 4 weeks, known as 'Long COVID'. Many gastrointestinal (GI) symptoms persist as part of this syndrome; yet, an approach to treatment remains unclear. Prior studies have demonstrated the efficacy of complementary and alternative medicine (CAM) for the treatment of acute COVID-19 infections, but little data exist regarding the potential use of CAM in the treatment of Long COVID.

Objectives

Identify CAM approaches useful in treating the GI symptoms of Long COVID.

Design

A systematic review of studies reporting on the use of CAM for the treatment of GI symptoms of Long COVID was performed.

Data Sources and Methods

Five electronic databases were searched from January 2019 to November 2022. Studies describing the use of CAM to treat GI symptoms of Long COVID were included and assessed by two independent reviewers. Studies not reporting on GI symptoms or using CAM were excluded. Studies chosen for final review underwent quality and bias assessment using predetermined criteria. The extracted data were synthesized utilizing a framework derived from the National Center of Complementary and Integrative Health categories.

Results

The initial search yielded 396 articles. After applying the eligibility criteria, a total of four studies (three case reports and one case series) were included for final review. Two studies used nutritional supplements and two studies used traditional Chinese medicine. Reductions in nausea, loss of appetite, diarrhea, acid reflux, epigastric pain, and bloating were reported.

Conclusion

This is the first systematic review to explore the role of CAM in treating GI manifestations of Long COVID. The review identified four studies, all reporting reductions in the GI symptoms of Long COVID. Despite the positive studies included in this review, the overall search yielded few results, all of which were non-experimental. As the post-infectious sequelae of COVID-19 become better recognized in the wake of the pandemic, higher-quality clinical studies are needed.

Coronaviral Main Protease Induces LPCAT3 Cleavage and Endoplasmic Reticulum (ER) Stress

Zoonotic coronaviruses infect mammals and birds, causing pulmonary and gastrointestinal infections. Some animal coronaviruses, such as the porcine epidemic diarrhea virus (PEDV) and transmissible gastroenteritis virus (TGEV), lead to severe diarrhea and animal deaths. Gastrointestinal symptoms were also found in COVID-19 and SARS patients. However, the pathogenesis of gastrointestinal symptoms in coronavirus diseases remains elusive. In this study, the main protease-induced LPCAT3 cleavage was monitored by exogenous gene expression and protease inhibitors, and the related regulation of gene expression was confirmed by qRT-PCR and gene knockdown. Interestingly, LPCAT3 plays an important role in lipid absorption in the intestines. The Mpro of coronaviruses causing diarrhea, such as PEDV and MERS-CoV, but not the Mpro of HCoV-OC43 and HCoV-HKU1, which could induce LPCAT3 cleavage. Mutagenesis analysis and inhibitor experiments indicated that LPCAT3 cleavage was independent of the catalytic activity of Mpro. Moreover, LPCAT3 cleavage in cells boosted CHOP and GRP78 expression, which were biomarkers of ER stress. Since LPCAT3 is critical for lipid absorption in the intestines and malabsorption may lead to diarrhea in coronavirus diseases, Mpro-induced LPCAT3 cleavage might trigger gastrointestinal symptoms during coronavirus infection.

[Post-COVID-19 syndrome]

In the aftermath of acute infection with the severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2), a large number of symptoms persist or appear, constituting a real syndrome called "long COVID-19" or "post-COVID- 19" or "post-acute COVID-19 syndrome". Its incidence is very high, half of patients showing at least one symptom at 4-6 months after Coronarovirus infectious disease 2019 (COVID-19). They can affect many organs. The most common symptom is persistent fatigue, similar to that seen after other viral infections. Radiological pulmonary sequelae are relatively rare and not extensive. On the other hand, functional respiratory symptoms, primarily dyspnoea, are much more frequent. Dysfunctional breathing is a significant cause of dyspnoea. Cognitive disorders and psychological symptoms are also very common, with anxiety, depression and post-traumatic stress symptoms being widely described. On the other hand, cardiac, endocrine, cutaneous, digestive or renal sequelae are rarer. The symptoms generally improve after several months, even if their prevalence at two years remains significant. Most of the symptoms are favored by the severity of the initial illness, and the psychic symptoms by the female sex. The pathophysiology of most symptoms is poorly understood. The influence of the treatments used in the acute phase is also important. Vaccination, on the other hand, seems to reduce their incidence. The sheer number of affected patients makes long-term COVID-19 syndrome a public health challenge.

Gastrointestinal disorders in post-COVID syndrome. Clinical guidelines

Summary Post- COVID syndrome refers to the long-term consequences of a new coronavirus infection COVID-19, which includes a set of symptoms that develop or persist after COVID-19. Symptoms of gastrointestinal disorders in post- COVID syndrome, due to chronic infl ammation, the consequences of organ damage, prolonged hospitalization, social isolation, and other causes, can be persistent and require a multidisciplinary approach. The presented clinical practice guidelines consider the main preventive and therapeutic and diagnostic approaches to the management of patients with gastroenterological manifestations of postCOVID syndrome. The Guidelines were approved by the 17th National Congress of Internal Medicine and the 25th Congress of Gastroenterological Scientifi c Society of Russia.

Trajectory of Gastrointestinal Symptoms in Previously Hospitalized COVID-19 Survivors: The Long COVID Experience Multicenter Study

This multicenter cohort study used Sankey plots and exponential bar plots to visualize the fluctuating evolution and the trajectory of gastrointestinal symptoms in previously hospitalized COVID-19 survivors during the first 18 months after acute SARS-CoV-2 infection. A total of 1266 previously hospitalized COVID-19 survivors were assessed at four points: hospital admission (T0), at 8.4 months (T1), at 13.2 months (T2), and at 18.3 months (T3) after hospitalization. Participants were asked about their overall gastrointestinal symptoms and particularly diarrhea. Clinical and hospitalization data were collected from hospital medical records. The prevalence of overall gastrointestinal post-COVID symptomatology was 6.3% (n = 80) at T1, 3.99% (n = 50) at T2 and 2.39% (n = 32) at T3. The prevalence of diarrhea decreased from 10.69% (n = 135) at hospital admission (T0), to 2.55% (n = 32) at T1, to 1.04% (n = 14) at T2, and to 0.64% (n = 8) at T3. The Sankey plots revealed that just 20 (1.59%) and 4 (0.32%) patients exhibited overall gastrointestinal post-COVID symptoms or diarrhea, respectively, throughout the whole follow-up period. The recovery fitted exponential curves revealed a decreasing prevalence trend, showing that diarrhea and gastrointestinal symptoms recover during the first two or three years after COVID-19 in previously hospitalized COVID-19 survivors. The regression models did not reveal any symptoms to be associated with the presence of gastrointestinal post-COVID symptomatology or post-COVID diarrhea at hospital admission or at T1. The use of Sankey plots revealed the fluctuating evolution of gastrointestinal post-COVID symptoms during the first two years after infection. In addition, exponential bar plots revealed the decreased prevalence of gastrointestinal post-COVID symptomatology during the first three years after infection.

Role of the microbiota-gut-brain axis in postacute COVID syndrome

The COVID-19 pandemic has resulted in the infection of hundreds of millions of individuals over the past 3 years, coupled with millions of deaths. Along with these more acute impacts of infection, a large subset of patients has developed symptoms that collectively comprise "postacute sequelae of COVID-19" (PASC, also known as long COVID), which can persist for months and maybe even years. In this review, we outline the current knowledge on the role of impaired microbiota-gut-brain (MGB) axis signaling in the development of PASC and the potential mechanisms involved, which may lead to a better understanding of disease progression and treatment options in the future.

Sequelae of long COVID, known and unknown: A review of updated information

Over three years have passed since the COVID-19 pandemic started. The dangerousness and impact of COVID-19 should definitely not be ignored or underestimated. Other than the symptoms of acute infection, the long-term symptoms associated with SARS-CoV-2 infection, which are referred to here as "sequelae of long COVID (LC)", are also a conspicuous global public health concern. Although such sequelae were well-documented, the understanding of and insights regarding LC-related sequelae remain inadequate due to the limitations of previous studies (the follow-up, methodological flaws, heterogeneity among studies, etc.). Notably, robust evidence regarding diagnosis and treatment of certain LC sequelae remain insufficient and has been a stumbling block to better management of these patients. This awkward situation motivated us to conduct this review. Here, we comprehensively reviewed the updated information, particularly focusing on clinical issues. We attempt to provide the latest information regarding LC-related sequelae by systematically reviewing the involvement of main organ systems. We also propose paths for future exploration based on available knowledge and the authors' clinical experience. We believe that these take-home messages will be helpful to gain insights into LC and ultimately benefit clinical practice in treating LC-related sequelae.

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.

Gastrointestinal and Hepatobiliary Symptoms and Disorders with Long (Chronic) COVID Infection

Long COVID is a novel syndrome characterizing new or persistent symptoms weeks after COVID-19 infection and involving multiple organ systems. This review summarizes the gastrointestinal and hepatobiliary sequelae of long COVID syndrome. It describes potential biomolecular mechanisms, prevalence, preventative measures, potential therapies, and health care and economic impact of long COVID syndrome, particularly of its gastrointestinal (GI) and hepatobiliary manifestations.

Diarrhea and Coronavirus Disease 2019 Infection

The global coronavirus disease-2019 (COVID-19) pandemic has caused significant morbidity and mortality, thoroughly affected daily living, and caused severe economic disruption throughout the world. Pulmonary symptoms predominate and account for most of the associated morbidity and mortality. However, extrapulmonary manifestations are common in COVID-19 infections, including gastrointestinal (GI) symptoms, such as diarrhea. Diarrhea affects approximately 10% to 20% of COVID-19 patients. Diarrhea can occasionally be the presenting and only COVID-19 symptom. Diarrhea in COVID-19 subjects is usually acute but is occasionally chronic. It is typically mild-to-moderate and nonbloody. It is usually much less clinically important than pulmonary or potential thrombotic disorders. Occasionally the diarrhea can be profuse and life-threatening. The entry receptor for COVID-19, angiotensin converting enzyme-2, is found throughout the GI tract, especially in the stomach and small intestine, which provides a pathophysiologic basis for local GI infection. COVID-19 virus has been documented in feces and in GI mucosa. Treatment of COVID-19 infection, especially antibiotic therapy, is a common culprit of the diarrhea, but secondary infections including bacteria, especially Clostridioides difficile, are sometimes implicated. Workup for diarrhea in hospitalized patients usually includes routine chemistries; basic metabolic panel; and a complete hemogram; sometimes stool studies, possibly including calprotectin or lactoferrin; and occasionally abdominal CT scan or colonoscopy. Treatment for the diarrhea is intravenous fluid infusion and electrolyte supplementation as necessary, and symptomatic antidiarrheal therapy, including Loperamide, kaolin-pectin, or possible alternatives. Superinfection with C difficile should be treated expeditiously. Diarrhea is prominent in post-COVID-19 (long COVID-19), and is occasionally noted after COVID-19 vaccination. The spectrum of diarrhea in COVID-19 patients is presently reviewed including the pathophysiology, clinical presentation, evaluation, and treatment.

COVID-19 and Inflammatory Bowel Disease

The COVID-19 pandemic caused by the SARS-CoV-2 virus represents an unprecedented global health crisis. Safe and effective vaccines were rapidly developed and deployed that reduced COVID-19-related severe disease, hospitalization, and death. Patients with inflammatory bowel disease are not at increased risk of severe disease or death from COVID-19, and data from large cohorts of patients with inflammatory bowel disease demonstrate that COVID-19 vaccination is safe and effective. Ongoing research is clarifying the long-term impact of SARS-CoV-2 infection on patients with inflammatory bowel disease, long-term immune responses to COVID-19 vaccination, and optimal timing for repeated COVID-19 vaccination doses.

The Prevalence of Irritable Bowel Syndrome after Severe Acute Respiratory Syndrome Coronavirus 2 Infection and Their Association: A Systematic Review and Meta-Analysis of Observational Studies

AIM

Investigate the prevalence of irritable bowel syndrome (IBS) after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and assess the association between IBS and SARS-CoV-2 infection.

METHODS

A systematic literature search for PubMed, Web of Science, Embase, Scopus, and the Cochrane Library was performed to identify all reports published before 31 December 2022. The confidence interval (CI), estimation effect (ES) of prevalence, and risk ratios (RR) were calculated to evaluate the prevalence of IBS after SARS-CoV-2 infection and their association. Individual results were pooled by the random-effects (RE) model. Subgroup analyses conducted a further investigation of the results. We employed funnel plots, Egger's test, and Begg's test to evaluate publication bias. Sensitivity analysis was performed for the assessment of the robustness of the result.

RESULTS

The data on IBS prevalence after SARS-CoV-2 infection were extracted from two cross-sectional studies and ten longitudinal studies from nineteen countries with 3950 individuals. The IBS prevalence after SARS-CoV-2 infection ranges from 3% to 91% in different countries, and the overall pooled prevalence of IBS following SARS-CoV-2 infection is 15% (ES: 0.15; 95% CI, 0.11-0.20; p = 0.000). The data on the association between IBS and SARS-CoV-2 infection were extracted from six cohort studies from fifteen countries with 3595 individuals. The risk of IBS increased following SARS-CoV-2 infection but was not significant (RR: 1.82; 95% CI, 0.90-3.69; p = 0.096).

CONCLUSIONS

In conclusion, the overall pooled prevalence of IBS following SARS-CoV-2 infection was 15%, and SARS-CoV-2 infection increased the overall risk of IBS but was not statistically significant. Further extra high-quality epidemiological evidence and studies to clarify the underlying mechanism of IBS following SARS-CoV-2 infection are needed.

LitCovid in 2022: an information resource for the COVID-19 literature

LitCovid (https://www.ncbi.nlm.nih.gov/research/coronavirus/)-first launched in February 2020-is a first-of-its-kind literature hub for tracking up-to-date published research on COVID-19. The number of articles in LitCovid has increased from 55 000 to ∼300 000 over the past 2.5 years, with a consistent growth rate of ∼10 000 articles per month. In addition to the rapid literature growth, the COVID-19 pandemic has evolved dramatically. For instance, the Omicron variant has now accounted for over 98% of new infections in the United States. In response to the continuing evolution of the COVID-19 pandemic, this article describes significant updates to LitCovid over the last 2 years. First, we introduced the long Covid collection consisting of the articles on COVID-19 survivors experiencing ongoing multisystemic symptoms, including respiratory issues, cardiovascular disease, cognitive impairment, and profound fatigue. Second, we provided new annotations on the latest COVID-19 strains and vaccines mentioned in the literature. Third, we improved several existing features with more accurate machine learning algorithms for annotating topics and classifying articles relevant to COVID-19. LitCovid has been widely used with millions of accesses by users worldwide on various information needs and continues to play a critical role in collecting, curating and standardizing the latest knowledge on the COVID-19 literature.