Global Prevalence of Post COVID-19 Condition or Long COVID: A Meta-Analysis and Systematic Review

Association Between BNT162b2 Vaccination and Long COVID After Infections Not Requiring Hospitalization in Health Care Workers

This study examines the risk of long COVID following mRNA vaccination, compared with no vaccination, in health care workers in Italy who had COVID-19 infection.

Impact of the SARS-CoV-2 Virus Pandemic on Patients with Bronchiectasis: A Multicenter Study

BACKGROUND

Infection by SARS-CoV-2 has unquestionably had an impact on the health of patients with chronic respiratory airway diseases, such as COPD and asthma, but little information is available about its impact on patients with bronchiectasis. The objective of the present study was to analyze the effect of the SARS-CoV-2 pandemic on the state of health, characteristics, and clinical severity (including the number and severity of exacerbations) of patients with non-cystic fibrosis bronchiectasis.

METHODS

This study was multicenter, observational, and ambispective (with data collected before and during the SARS-CoV-2 pandemic), and included 150 patients diagnosed with non-cystic fibrosis bronchiectasis.

RESULTS

A significant drop was observed in the number and severity of the exacerbations (57% in all exacerbations and 50% in severe exacerbations) in the E-FACED and BSI multidimensional scores, in the pandemic, compared with the pre-pandemic period. There was also a drop in the percentage of sputum samples positive for pathogenic microorganisms in general (from 58% to 44.7%) and, more specifically, Pseudomonas aeruginosa (from 23.3% to 13.3%) and Haemophilus influenzae (from 21.3% to 14%).

CONCLUSIONS

During the SARS-CoV-2 period, a significant reduction was observed in the exacerbations, severity, and isolations of pathogenic microorganisms in patients with bronchiectasis.

Long-Term Health Symptoms and Sequelae Following SARS-CoV-2 Infection: An Evidence Map

Post-COVID-19 conditions, also known as 'Long-COVID-19', describe a longer and more complex course of illness than acute COVID-19 with no widely accepted uniform case definition. We aimed to map the available evidence on persistent symptoms and sequelae following SARS-CoV-2 in children and adults. We searched the Cochrane COVID-19 Study Register and the WHO COVID-19 Global literature on coronavirus disease database on 5 November 2021. We included longitudinal and cross-sectional studies and we extracted their characteristics, including the type of core outcomes for post-COVID-19 conditions. We included 565 studies (657 records). Most studies were uncontrolled cohort studies. The median follow-up time was 13 weeks (IQR 9 to 24). Only 72% of studies were conducted in high-income countries, 93% included unvaccinated adults with mild-to-critical disease, only 10% included children and adolescents, and less than 5% included children under the age of five. While most studies focused on health symptoms, including respiratory symptoms (71%), neurological symptoms (57%), fatigue (54%), pain (50%), mental functioning (43%), cardiovascular functioning (40%), and post-exertion symptoms (28%), cognitive function (26%), fewer studies assessed other symptoms such as overall recovery (24%), the need for rehabilitation (18%), health-related quality of life (16%), changes in work/occupation and study (10%), or survival related to long-COVID-19 (4%). There is a need for controlled cohort studies with long-term follow-up and a focus on overall recovery, health-related quality of life, and the ability to perform daily tasks. Studies need to be extended to later phases of the pandemic and countries with low resources.

Distinguishing features of Long COVID identified through immune profiling

SARS-CoV-2 infection can result in the development of a constellation of persistent sequelae following acute disease called post-acute sequelae of COVID-19 (PASC) or Long COVID 1-3 . Individuals diagnosed with Long COVID frequently report unremitting fatigue, post-exertional malaise, and a variety of cognitive and autonomic dysfunctions 1-3 ; however, the basic biological mechanisms responsible for these debilitating symptoms are unclear. Here, 215 individuals were included in an exploratory, cross-sectional study to perform multi-dimensional immune phenotyping in conjunction with machine learning methods to identify key immunological features distinguishing Long COVID. Marked differences were noted in specific circulating myeloid and lymphocyte populations relative to matched control groups, as well as evidence of elevated humoral responses directed against SARS-CoV-2 among participants with Long COVID. Further, unexpected increases were observed in antibody responses directed against non-SARS-CoV-2 viral pathogens, particularly Epstein-Barr virus. Analysis of circulating immune mediators and various hormones also revealed pronounced differences, with levels of cortisol being uniformly lower among participants with Long COVID relative to matched control groups. Integration of immune phenotyping data into unbiased machine learning models identified significant distinguishing features critical in accurate classification of Long COVID, with decreased levels of cortisol being the most significant individual predictor. These findings will help guide additional studies into the pathobiology of Long COVID and may aid in the future development of objective biomarkers for Long COVID.

Long COVID symptomatology after twelve months and its impact on quality of life according to initial COVID-19 disease severity

Background

“Long COVID” is characterized by a variety of symptoms and an important burden for affected people. Our objective was to describe long COVID symptomatology according to initial coronavirus disease 2019 (COVID-19) severity.

Methods

Predi-COVID cohort study participants, recruited at the time of acute COVID-19 infection, completed a detailed 12-month symptom and quality of life questionnaire. Frequencies and co-occurrences of symptoms were assessed.

Results

Among the 289 participants who fully completed the 12-month questionnaire, 59.5% reported at least 1 symptom, with a median of 6 symptoms. Participants with an initial moderate or severe acute illness declared more frequently 1 or more symptoms (82.6% vs 38.6%, P < .001) and had on average 6.8 more symptoms (95% confidence interval, 4.18–9.38) than initially asymptomatic participants who developed symptoms after the acute infection. Overall, 12.5% of the participants could not envisage coping with their symptoms in the long term. Frequently reported symptoms, such as neurological and cardiovascular symptoms, but also less frequent ones such as gastrointestinal symptoms, tended to cluster.

Conclusions

Frequencies and burden of symptoms present 12 months after acute COVID-19 infection increased with the severity of the acute illness. Long COVID likely consists of multiple subcategories rather than a single entity. This work will contribute to the better understanding of long COVID and to the definition of precision health strategies.

Clinical Trials Registration

NCT04380987.

Valuing COVID-19 Morbidity Risk Reductions

Many economic analyses, including those that address the COVID-19 pandemic, focus on the value of averting deaths and do not include the value of averting nonfatal illnesses. Yet incorporating the value of averting nonfatal cases may change conclusions about the desirability of the policy. While per case values may be small, the number of nonfatal cases is often large, far outstripping the number of fatal cases. The value of averting nonfatal cases is also increasingly important in evaluating COVID-19 policy options as vaccine- and infection-related immunity and treatments reduce the case-fatality rate. Unfortunately, little valuation research is available that explicitly addresses COVID-19 morbidity. We describe and implement an approach for approximating the value of averting nonfatal illnesses or injuries and apply it to COVID-19 in the United States. We estimate gains from averting COVID-19 morbidity of about 0.01 quality-adjusted life year (QALY) per mild case averted, 0.02 QALY per severe case, and 3.15 QALYs per critical case. These gains translate into monetary values of about $5,300 per mild case, $11,000 per severe case, and $1.8 million per critical case. While these estimates are imprecise, they suggest the magnitude of the effects.

Musculoskeletal symptoms in patients with long COVID: A cross-sectional study on Iranian patients

Background and objectives

Latest studies have revealed that an increasing number of Corona Virus Disease of 2019 (COVID-19) patients may continue to feel symptoms after the acute phase. This study aimed to evaluate the prevalence of musculoskeletal symptoms after the acute phase of COVID-19 and its associated factors.

Methods

We designed a cross-sectional study from January 2021 to April 2021. An online questionnaire was designed and sent to patients who had recovered from COVID-19. The questionnaire contained questions on participants' demographic characteristics, COVID-19 course at its acute phase, and musculoskeletal symptoms after recovering from COVID-19. Musculoskeletal symptoms associations with patients’ characteristic and COVID-19 course was evaluated.

Result

239 patients, including 72 (30.1%) males and 167 (69.9%) females with a mean age of 37.96 years (SD = 11.19), were included in the study. 98.74% of our patients had experienced at least one musculoskeletal symptom after recovering from COVID-19, and the most common symptom was fatigue, as 91.2% of participants experienced this symptom, followed by myalgia, headache, and low back pain. High BMI, hospitalization, and ICU admission were associated with a higher risk of musculoskeletal symptoms.

Conclusion

This study indicated a high prevalence of persistent musculoskeletal symptoms among patients who recovered from COVID-19. Modifiable factors, such as BMI, can be targeted to reduce the prevalence of musculoskeletal symptoms in COVID-19 survivors and reduce its burden.

Pulmonale Manifestationen bei Long-COVID

Hintergrund

Pulmonale Manifestationen sind sehr häufige Folgeerscheinungen nach einer Severe-acute-respiratory-syndrome-coronavirus-type-2(SARS-CoV-2)-Infektion, die unter dem Begriff Long-COVID-Syndrom (COVID „coronavirus disease“) zusammengefasst werden.

Ziel und Methoden

Zusammenfassung der aktuellen Literatur zu den pulmonalen Manifestationen mit einem Fokus auf Expertenempfehlungen.

Ergebnisse

Dyspnoe ist nach der chronischen Fatigue das häufigste Symptom bei Patienten mit Long-COVID-Syndrom. Auffällige Befunde finden sich vor allem nach schwerem akutem COVID-19-Verlauf und beinhalten radiologische Veränderungen im Sinne interstitieller Lungenerkrankungen, restriktive lungenfunktionelle Befunde und Einschränkungen der Diffusionskapazität als häufigsten pathologischen Befund. Obwohl sich sowohl Beschwerden als auch pathologische pulmonale Befunde im Verlauf bessern, können einige Patienten noch Monate nach der akuten Infektion unter Auffälligkeiten leiden. Dabei ist die Relevanz der pathologischen Befunde sowie eine Beteiligung funktioneller respiratorischer Einschränkungen, einer kardiopulmonalen Dekonditionierung, nichtsomatischer Ursachen und vorbestehender Erkrankungen aktuell unklar. Die diagnostische Abklärung fokussiert entsprechend auf Risikopatienten und schließt neben einer bildgebenden und lungenfunktionellen Abklärung eine Belastungsuntersuchung und bei unklaren Befunden eine Echokardiographie zur Diagnose einer pulmonalvaskulären Komponente ein. Die therapeutischen Möglichkeiten beinhalten aktuell die leitliniengerechte Therapie von Ursachen der Beschwerden (beispielsweise interstitielle Lungenerkrankungen, Husten) und Rehabilitationsmaßnahmen.

Schlussfolgerung

Das aktuelle Wissen zum Krankheitsbild wird ständig erweitert, allerdings existieren aufgrund mangelnder Studienlage noch keine evidenzbasierten Leitlinien zur Diagnostik und Therapie pulmonaler Manifestationen beim Long-COVID-Syndrom.

Hydroxytyrosol Recovers SARS-CoV-2-PLpro-Dependent Impairment of Interferon Related Genes in Polarized Human Airway, Intestinal and Liver Epithelial Cells

The SARS-CoV-2 pandemic has caused approximately 6.3 million deaths, mainly due to the acute respiratory distress syndrome or multi-organ failure that characterizes COVID-19 acute disease. Post-acute COVID-19 syndrome, also known as long-COVID, is a condition characterized by a complex of symptoms that affects 10–20% of the individuals who have recovered from the infection. Scientific and clinical evidence demonstrates that long-COVID can develop in both adults and children. It has been hypothesized that multi-organ effects of long-COVID could be associated with the persistence of virus RNA/proteins in host cells, but the real mechanism remains to be elucidated. Therefore, we sought to determine the effects of the exogenous expression of the papain-like protease (PLpro) domain of the non-structural protein (NSP3) of SARS-CoV-2 in polarized human airway (Calu-3), intestinal (Caco-2), and liver (HepG2) epithelial cells, and to evaluate the ability of the natural antioxidant hydroxytyrosol (HXT) in neutralizing these effects. Our results demonstrated that PLpro was able to induce a cascade of inflammatory genes and proteins (mainly associated with the interferon pathway) and increase the apoptotic rate and expression of several oxidative stress markers in all evaluated epithelial cells. Noteably, the treatment with 10 μM HXT reverted PL-pro-dependent effects almost completely. This study provides the first evidence that SARS-CoV-2 PLpro remaining in host cells after viral clearance may contribute to the pathogenetic mechanisms of long-COVID. These effects may be counteracted by natural antioxidants. Further clinical and experimental studies are necessary to confirm this hypothesis.

Long COVID and its Management

The pandemic of COVID-19 is the biggest public health crisis in 21^st Century. Besides the acute symptoms after infection, patients and society are also being challenged by the long-term health complications associated with COVID-19, commonly known as long COVID. While health professionals work hard to find proper treatments, large amount of knowledge has been accumulated in recent years. In order to deal with long COVID efficiently, it is important for people to keep up with current progresses and take proactive actions on long COVID. For this purpose, this review will first introduce the general background of long COVID, and then discuss its risk factors, diagnostic indicators and management strategies. This review will serve as a useful resource for people to understand and prepare for long COVID that will be with us in the foreseeable future.

Exercise Limitation after Critical Versus Mild COVID-19 Infection: A Metabolic Perspective

Exercise limitation in COVID-19 survivors is poorly explained. In this retrospective study, cardiopulmonary exercise testing (CPET) was coupled with an oxidative stress assessment in COVID-19 critically ill survivors (ICU group). Thirty-one patients were included in this group. At rest, their oxygen uptake (VO₂) was elevated (8 [5.6–9.7] mL/min/kg). The maximum effort was reached at low values of workload and VO₂ (66 [40.9–79.2]% and 74.5 [62.6–102.8]% of the respective predicted values). The ventilatory equivalent for carbon dioxide remained within normal ranges. Their metabolic efficiency was low: 15.2 [12.9–17.8]%. The 50% decrease in VO₂ after maximum effort was delayed, at 130 [120–170] s, with a still-high respiratory exchange ratio (1.13 [1–1.2]). The blood myeloperoxidase was elevated (92 [75.5–106.5] ng/mL), and the OSS was altered. The CPET profile of the ICU group was compared with long COVID patients after mid-disease (MLC group) and obese patients (OB group). The MLC patients (n = 23) reached peak workload and predicted VO₂ values, but their resting VO₂, metabolic efficiency, and recovery profiles were similar to the ICU group to a lesser extent. In the OB group (n = 15), no hypermetabolism at rest was observed. In conclusion, the exercise limitation after a critical COVID-19 bout resulted from an altered metabolic profile in the context of persistent inflammation and oxidative stress. Altered exercise and metabolic profiles were also observed in the MLC group. The contribution of obesity on the physiopathology of exercise limitation after a critical bout of COVID-19 did not seem relevant.

A nationwide questionnaire study of post-acute symptoms and health problems after SARS-CoV-2 infection in Denmark

A considerable number of individuals infected with SARS-CoV-2 continue to experience symptoms after the acute phase. Here, we report findings from a nationwide questionnaire study in Denmark including 61,002 RT-PCR confirmed SARS-CoV-2 cases and 91,878 test-negative controls aged 15-years or older. Six to twelve months after the test, the risks of 18 out of 21 symptoms were elevated among test-positives. The largest adjusted risk differences (RD) were observed for dysosmia (RD = 10.92%, 95% CI 10.68-11.21%), dysgeusia (RD = 8.68%, 95% CI 8.43-8.93%), fatigue/exhaustion (RD = 8.43%, 95%CI 8.14-8.74%), dyspnea (RD = 4.87%, 95% CI 4.65-5.09%) and reduced strength in arms/legs (RD = 4.68%, 95% CI 4.45-4.89%). During the period from the test and until completion of the questionnaire, new diagnoses of anxiety (RD = 1.15%, 95% CI 0.95-1.34%) or depression (RD = 1.00%, 95% CI 0.81-1.19%) were also more common among test-positives. Even in a population where the majority of test-positives were not hospitalized, a considerable proportion experiences symptoms up to 12 months after infection. Being female or middle-aged increases risks.

Assessment of SARS-CoV-2 Infection According to Previous Metabolic Status and Its Association with Mortality and Post-Acute COVID-19

Background. SARS-CoV-2 infection was analyzed according to previous metabolic status and its association with mortality and post-acute COVID-19. Methods. A population-based observational retrospective study was conducted on a cohort of 110,726 patients aged 12 years or more who were diagnosed with COVID-19 infection between June 1st, 2021, and 28 February 2022 on the island of Gran Canaria, Spain. Results. In the 347 patients who died, the combination of advanced age, male sex, cancer, immunosuppressive therapy, coronary heart disease, elevated total cholesterol and reduced high-density lipoprotein cholesterol (HDL-C) was strongly predictive of mortality (p < 0.05). In the 555 patients who developed post-acute COVID-19, the persistence of symptoms was most frequent in women, older subjects and patients with obstructive sleep apnea syndrome, asthma, elevated fasting glucose levels or elevated total cholesterol (p < 0.05). A complete vaccination schedule was associated with lower mortality (incidence rate ratio (IRR) 0.5, 95%CI 0.39−0.64; p < 0.05) and post-acute COVID-19 (IRR 0.37, 95%CI 0.31−0.44; p < 0.05). Conclusions. Elevated HDL-C and elevated total cholesterol were significantly associated with COVID-19 mortality. Elevated fasting glucose levels and elevated total cholesterol were risk factors for the development of post-acute COVID-19.

Long COVID and symptom trajectory in a representative sample of Americans in the first year of the pandemic

People who have COVID-19 can experience symptoms for months. Studies on long COVID in the population lack representative samples and longitudinal data focusing on new-onset symptoms occurring with COVID while accounting for pre-infection symptoms. We use a sample representing the U.S. community population from the Understanding America Study COVID-19 Survey, which surveyed around 8000 respondents bi-weekly from March 2020 to March 2021. Our final sample includes 308 infected individuals who were interviewed one month before, around the time of, and 12 weeks after infection. About 23% of the sample experienced new-onset symptoms during infection which lasted for more than 12 weeks, and thus can be considered as having long COVID. The most common new-onset persistent symptoms among those included in the study were headache (22%), runny or stuffy nose (19%), abdominal discomfort (18%), fatigue (17%), and diarrhea (13%). Long COVID was more likely among obese individuals (OR = 5.44, 95% CI 2.12–13.96) and those who experienced hair loss (OR = 6.94, 95% CI 1.03–46.92), headache (OR = 3.37, 95% CI 1.18–9.60), and sore throat (OR = 3.56, 95% CI 1.21–10.46) during infection. There was a lack of evidence relating risk to age, gender, race/ethnicity, education, current smoking status, or comorbid chronic conditions. This work provides national estimates of long COVID in a representative sample after accounting for pre-infection symptoms.

Prevalence of and factors associated with post-COVID-19 condition in the 12 months following the diagnosis of COVID-19 in adults followed in general practices in Germany

Background

Little is known about the epidemiology of post-coronavirus disease 2019 (COVID-19) condition (PCC) in primary care practices. Therefore, this study aimed to investigate the prevalence of and the factors associated with PCC in the 12 months after the diagnosis of COVID-19 in patients followed in general practices in Germany.

Methods

This retrospective cohort study included adults aged ≥18 years who were diagnosed for the first time with COVID-19 (index date) in 1 of 855 general practices in Germany between October 2020 and August 2021 (Disease Analyzer database; IQVIA). The outcome was the occurrence of PCC 91 to 365 days after the index date. Covariates included age, sex, and comorbidities documented in the 12 months before the index date. The association between covariates and PCC was assessed using a multivariable logistic regression model.

Results

We included 51 630 patients in this study (mean age, 47.1 [standard deviation, 19.8] years; 54.3% women). The prevalence of PCC was 8.3%. Age >30 years (odds ratios [ORs] ranging from 1.40 for 31–45 years to 2.10 for 46–60 years) and female sex (OR = 1.23) were positively and significantly associated with PCC compared with age 18–30 years and male sex, respectively. There was also a significant relationship of PCC with asthma (OR = 1.38), reaction to severe stress, and adjustment disorders (OR = 1.24), and somatoform disorders (OR = 1.23).

Conclusions

Post-COVID-19 condition was found in the 12 months after the diagnosis of COVID-19 in approximately 8% of adults from general practices in Germany. More data from other settings are warranted to confirm these findings.

Identifying Profiles and Symptoms of Patients With Long COVID in France: Data Mining Infodemiology Study Based on Social Media

BACKGROUND

Long COVID-a condition with persistent symptoms post COVID-19 infection-is the first illness arising from social media. In France, the French hashtag #ApresJ20 described symptoms persisting longer than 20 days after contracting COVID-19. Faced with a lack of recognition from medical and official entities, patients formed communities on social media and described their symptoms as long-lasting, fluctuating, and multisystemic. While many studies on long COVID relied on traditional research methods with lengthy processes, social media offers a foundation for large-scale studies with a fast-flowing outburst of data.

OBJECTIVE

We aimed to identify and analyze Long Haulers' main reported symptoms, symptom co-occurrences, topics of discussion, difficulties encountered, and patient profiles.

METHODS

Data were extracted based on a list of pertinent keywords from public sites (eg, Twitter) and health-related forums (eg, Doctissimo). Reported symptoms were identified via the MedDRA dictionary, displayed per the volume of posts mentioning them, and aggregated at the user level. Associations were assessed by computing co-occurrences in users' messages, as pairs of preferred terms. Discussion topics were analyzed using the Biterm Topic Modeling; difficulties and unmet needs were explored manually. To identify patient profiles in relation to their symptoms, each preferred term's total was used to create user-level hierarchal clusters.

RESULTS

Between January 1, 2020, and August 10, 2021, overall, 15,364 messages were identified as originating from 6494 patients of long COVID or their caregivers. Our analyses revealed 3 major symptom co-occurrences: asthenia-dyspnea (102/289, 35.3%), asthenia-anxiety (65/289, 22.5%), and asthenia-headaches (50/289, 17.3%). The main reported difficulties were symptom management (150/424, 35.4% of messages), psychological impact (64/424,15.1%), significant pain (51/424, 12.0%), deterioration in general well-being (52/424, 12.3%), and impact on daily and professional life (40/424, 9.4% and 34/424, 8.0% of messages, respectively). We identified 3 profiles of patients in relation to their symptoms: profile A (n=406 patients) reported exclusively an asthenia symptom; profile B (n=129) expressed anxiety (n=129, 100%), asthenia (n=28, 21.7%), dyspnea (n=15, 11.6%), and ageusia (n=3, 2.3%); and profile C (n=141) described dyspnea (n=141, 100%), and asthenia (n=45, 31.9%). Approximately 49.1% of users (79/161) continued expressing symptoms after more than 3 months post infection, and 20.5% (33/161) after 1 year.

CONCLUSIONS

Long COVID is a lingering condition that affects people worldwide, physically and psychologically. It impacts Long Haulers' quality of life, everyday tasks, and professional activities. Social media played an undeniable role in raising and delivering Long Haulers' voices and can potentially rapidly provide large volumes of valuable patient-reported information. Since long COVID was a self-titled condition by patients themselves via social media, it is imperative to continuously include their perspectives in related research. Our results can help design patient-centric instruments to be further used in clinical practice to better capture meaningful dimensions of long COVID.

Point Prevalence Estimates of Activity-Limiting Long-Term Symptoms among U.S. Adults ≥1 Month After Reported SARS-CoV-2 Infection, November 1, 2021

Background

Although most adults infected with SARS-CoV-2 fully recover, a proportion have ongoing symptoms, or post-COVID conditions (PCC), after infection. The objective of this analysis was to estimate the number of US adults with activity-limiting PCC on November 1, 2021.

Methods

We modeled the prevalence of PCC using reported infections occurring from February 1, 2020 – September 30, 2021, and population-based, household survey data on new activity-limiting symptoms ≥1 month following SARS-CoV-2 infection. From these data sources, we estimated the number and proportion of US adults with activity-limiting PCC on November 1, 2021, as 95% uncertainty intervals, stratified by sex and age. Sensitivity analyses adjusted for under-ascertainment of infections and uncertainty about symptom duration.

Results

On November 1, 2021, at least 3.0–5.0 million US adults were estimated to have activity-limiting PCC of ≥1 month duration, or 1.2%–1.9% of US adults. Population prevalence was higher in females (1.4%–2.2%) than males. The estimated prevalence after adjusting for under-ascertainment of infections was 1.7%–3.8%.

Conclusion

Millions of US adults were estimated to have activity-limiting PCC. These estimates can support future efforts to address the impact of PCC on the U.S. population.

HYGIEIA: HYpothesizing the Genesis of Infectious Diseases and Epidemics through an Integrated Systems Biology Approach

More than two years on, the COVID-19 pandemic continues to wreak havoc around the world and has battle-tested the pandemic-situation responses of all major global governments. Two key areas of investigation that are still unclear are: the molecular mechanisms that lead to heterogenic patient outcomes, and the causes of Post COVID condition (AKA Long-COVID). In this paper, we introduce the HYGIEIA project, designed to respond to the enormous challenges of the COVID-19 pandemic through a multi-omic approach supported by network medicine. It is hoped that in addition to investigating COVID-19, the logistics deployed within this project will be applicable to other infectious agents, pandemic-type situations, and also other complex, non-infectious diseases. Here, we first look at previous research into COVID-19 in the context of the proteome, metabolome, transcriptome, microbiome, host genome, and viral genome. We then discuss a proposed methodology for a large-scale multi-omic longitudinal study to investigate the aforementioned biological strata through high-throughput sequencing (HTS) and mass-spectrometry (MS) technologies. Lastly, we discuss how a network medicine approach can be used to analyze the data and make meaningful discoveries, with the final aim being the translation of these discoveries into the clinics to improve patient care.

Is post-COVID syndrome an autoimmune disease?

INTRODUCTION

: Coronavirus disease 2019 (COVID-19) causes a long-term and persistent condition with clinical features similar to previous virulent outbreaks and other epidemics. Currently, post-COVID syndrome (PCS) is recognized as a new entity in the context of SARS-CoV-2 infection. Though its pathogenesis is not completely understood, persistent inflammation from acute illness and the development of autoimmunity play a critical role in its development. As the pandemic develops, the increasing latent and overt autoimmunity cases indicate that PCS is at the intersection of autoimmunity.

AREAS COVERED

The mechanisms involved in the emergence of PCS, their similarities with post-viral and post-care syndromes, its inclusion in the spectrum of autoimmunity and possible targets for its treatment.

EXPERT OPINION

An autoimmune phenomenon plays a major role in most causative theories explaining PCS. Due to the wide scope of symptoms and pathophysiology associated with PCS, there is a need for both PCS definition and classification criteria (including severity scores). Longitudinal and controlled studies are necessary to better understand this new entity, and to confirm that PCS is the chronic phase of COVID-19 as well as to find what additional factors participate into its development. With the high prevalence of COVID-19 cases worldwide, together with the current evidence on latent autoimmunity in PCS, we may observe an increase of autoimmune diseases (ADs) in the coming years. Vaccination's effect on the development of PCS and ADs will also receive attention in the future. Health and social care services need to develop a new framework to deal with PCS.

The Multifaceted Manifestations of Multisystem Inflammatory Syndrome during the SARS-CoV-2 Pandemic

The novel coronavirus SARS-CoV-2, which has similarities to the 2002–2003 severe acute respiratory syndrome coronavirus known as SARS-CoV-1, causes the infectious disease designated COVID-19 by the World Health Organization (Coronavirus Disease 2019). Although the first reports indicated that activity of the virus is centered in the lungs, it was soon acknowledged that SARS-CoV-2 causes a multisystem disease. Indeed, this new pathogen causes a variety of syndromes, including asymptomatic disease; mild disease; moderate disease; a severe form that requires hospitalization, intensive care, and mechanical ventilation; multisystem inflammatory disease; and a condition called long COVID or postacute sequelae of SARS-CoV-2 infection. Some of these syndromes resemble previously described disorders, including those with no confirmed etiology, such as Kawasaki disease. After recognition of a distinct multisystem inflammatory syndrome in children, followed by a similar syndrome in adults, various multisystem syndromes occurring during the pandemic associated or related to SARS-CoV-2 began to be identified. A typical pattern of cytokine and chemokine dysregulation occurs in these complex syndromes; however, the disorders have distinct immunological determinants that may help to differentiate them. This review discusses the origins of the different trajectories of the inflammatory syndromes related to SARS-CoV-2 infection.

Perspective: COVID-19 and Its Neurologic Sequelae

COVID-19 led to a catastrophic, international, public health crisis after its first detection in 2019 [1]. Though it is primarily a respiratory virus, it impacts the central and peripheral nervous systems leading to further COVID-19-associated disability [2]. This Perspective reviews our current understanding of the neurological sequelae of COVID-19 and the gaps in our understanding of their treatment and epidemiology.

Long-COVID Syndrome and the Cardiovascular System: A Review of Neurocardiologic Effects on Multiple Systems

PURPOSE OF REVIEW

Long-COVID syndrome is a multi-organ disorder that persists beyond 12 weeks post-acute SARS-CoV-2 infection (COVID-19). Here, we provide a definition for this syndrome and discuss neuro-cardiology involvement due to the effects of (1) angiotensin-converting enzyme 2 receptors (the entry points for the virus), (2) inflammation, and (3) oxidative stress (the resultant effects of the virus).

RECENT FINDINGS

These effects may produce a spectrum of cardio-neuro effects (e.g., myocardial injury, primary arrhythmia, and cardiac symptoms due to autonomic dysfunction) which may affect all systems of the body. We discuss the symptoms and suggest therapies that target the underlying autonomic dysfunction to relieve the symptoms rather than merely treating symptoms. In addition to treating the autonomic dysfunction, the therapy also treats chronic inflammation and oxidative stress. Together with a full noninvasive cardiac workup, a full assessment of the autonomic nervous system, specifying parasympathetic and sympathetic (P&S) activity, both at rest and in response to challenges, is recommended. Cardiac symptoms must be treated directly. Cardiac treatment is often facilitated by treating the P&S dysfunction. Cardiac symptoms of dyspnea, chest pain, and palpitations, for example, need to be assessed objectively to differentiate cardiac from neural (autonomic) etiology. Long-term myocardial injury commonly involves P&S dysfunction. P&S assessment usually connects symptoms of Long-COVID to the documented autonomic dysfunction(s).

Cytokine Deficiencies in Patients with Long-COVID

Up to half of individuals who contract SARS-CoV-2 develop symptoms of long-COVID approximately three months after initial infection. These symptoms are highly variable, and the mechanisms inducing them are yet to be understood. We compared plasma cytokine levels from individuals with long-COVID to healthy individuals and found that those with long-COVID had 100% reductions in circulating levels of Interferon Gamma (IFNγ) and Interleukin-8 (IL-8). Additionally, we found significant reductions in levels of IL-6, IL-2, IL-17, IL-13, and IL-4 in individuals with long-COVID. We propose immune exhaustion as the driver of long-COVID, with the complete absence of IFNγ and IL-8preventing the lungs and other organs from healing after acute infection, and reducing the ability to fight off subsequent infections, both contributing to the myriad of symptoms suffered by those with long-COVID.