Multisystem inflammatory syndrome in children related to COVID-19: a systematic review

Innate immune response in acute critical illness: a narrative review

BACKGROUND

Activation of innate immunity is a first line of host defense during acute critical illness (ACI) that aims to contain injury and avoid tissue damages. Aberrant activation of innate immunity may also participate in the occurrence of organ failures during critical illness. This review aims to provide a narrative overview of recent advances in the field of innate immunity in critical illness, and to consider future potential therapeutic strategies.

MAIN TEXT

Understanding the underlying biological concepts supporting therapeutic strategies modulating immune response is essential in decision-making. We will develop the multiple facets of innate immune response, especially its cellular aspects, and its interaction with other defense mechanisms. We will first describe the pathophysiological mechanisms of initiation of innate immune response and its implication during ACI. We will then develop the amplification of innate immunity mediated by multiple effectors. Our review will mainly focus on myeloid and lymphoid cellular effectors, the major actors involved in innate immune-mediated organ failure. We will third discuss the interaction and integration of innate immune response in a global view of host defense, thus considering interaction with non-immune cells through immunothrombosis, immunometabolism and long-term reprogramming via trained immunity. The last part of this review will focus on the specificities of the immune response in children and the older population.

CONCLUSIONS

Recent understanding of the innate immune response integrates immunity in a highly dynamic global vision of host response. A better knowledge of the implicated mechanisms and their tissue-compartmentalization allows to characterize the individual immune profile, and one day eventually, to develop individualized bench-to-bedside immunomodulation approaches as an adjuvant resuscitation strategy.

Multisystem inflammatory syndrome in children: A review

AIM

To comprehensively review the literature on multisystem inflammatory syndrome in children (MIS-C).

METHODS

Narrative review of relevant studies published between April 2020 and January 2024.

RESULTS

MIS-C is a SARS-CoV-2-related hyperinflammatory syndrome developing 2-6 weeks after COVID-19 in genetically susceptible individuals. Persisting fever, mucocutaneous manifestations, GI and cardiac involvement, together with lymphopenia and elevated inflammatory and cardiac markers are the main clinical features. It is believed to recognise some pathogenetic and clinical overlap with Kawasaki disease. New case definitions have been proposed after an assessment of the diagnostic performance of existing criteria; epidemiological criterion is however progressively losing its usefulness as the pandemic turns into an endemic and in the areas with the highest rates of COVID-19 vaccination. Current guidelines recommend both intravenous immunoglobulin and glucocorticoids in the first-line immunomodulatory treatment, mainly based on comparative retrospective cohorts; the actual role of biologics remains to be adequately established. Strict follow-up is mandatory, especially for those with severe cardiac involvement, as longitudinal studies evaluate the long-term evolution of cardiac damage.

CONCLUSION

In this paper, we review the epidemiological, pathogenetic, clinical and prognostic features of MIS-C, and outline the main questions which still remain unanswered after more than 3 years of research.

Risks of Kawasaki disease and multisystem inflammatory syndrome in pediatric patients with COVID-19 infection: A TriNetX based cohort study

BACKGROUND

The associations of coronavirus disease (COVID-19) with Kawasaki disease (KD) and multisystem inflammatory syndrome in children (MIS-C) remain unclear. Few large-scale studies have estimated the cumulative incidence of MIS-C and KD after COVID-19 in children.

METHODS

Data were obtained from TriNetX. After propensity score matching was completed, data from 258 645 patients with COVID-19 (COVID-19 group) and 258 645 patients without COVID-19 (non-COVID-19 group) were analyzed using Cox regression. Hazard ratio (HR), 95% CI, and cumulative incidence of MIS-C and KD were calculated for both groups. A stratified analysis was performed to validate the results.

RESULTS

After matching for age at baseline and sex, the risks of MIS-C and KD were higher in the COVID-19 group than in the non-COVID-19 group (HR: 3.023 [95% CI, 2.323-3.933] and 1.736 [95% CI, 1.273-2.369], respectively). After matching for age at baseline, sex, race, ethnicity, and comorbidities, the risks of MIS-C and KD remained significantly higher in the COVID-19 group than in the non-COVID-19 group (HR: 2.899 [95% CI, 2.173-3.868] and 1.435 [95% CI, 1.030-2.000]). When stratified by age, the risk of MIS-C was higher in the COVID-19 group-for patients aged >5 years and ≤5 years (HR: 2.399 [95% CI, 1.683-3.418] and 2.673 [95% CI, 1.737-4.112], respectively)-than in the non-COVID-19 group. However, the risk of KD was elevated only in patients aged ≤5 years (HR: 1.808; 95% CI, 1.203-2.716). When stratified by COVID-19 vaccination status, the risks of MIS-C and KD were elevated in unvaccinated patients with COVID-19 (HR: 2.406 and 1.835, respectively).

CONCLUSION

Patients with COVID-19 who are aged <18 and ≤5 years have increased risks of MIS-C and KD, respectively. Further studies are required to confirm the role of COVID-19 in the pathogenesis of MIS-C and KD.

Multisystemic Inflammatory Syndrome in Children (MIS-C) With COVID-19 and Kidney Involvement: Poor Outcomes in a Case Series

Multisystemic inflammatory syndrome (Mis-C) has emerged in May 2020 as a serious complication of coronavirus disease (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV2). A total of 6 children presented to tertiary care hospitals with Mis-C, of which 5 (83%) have died during hospitalization. All included patients presented with respiratory symptoms (ranged from mild to severe acute respiratory distress syndrome) and gastrointestinal symptoms. Most of the patients are known to have medical illnesses. Pediatric Risk of Mortality (PRISM) IV score ranged from 3 to 87. All patients developed acidosis and varying stages of acute kidney injury and electrolyte disturbances. All were treated for coagulopathy, thrombocytopenia, bacterial infections as well as antiviral medications (either ritonavir or lopinavir). Most patients had chest X-ray changes either unilateral or bilateral lung changes. Multisystemic inflammatory syndrome is a rare, yet serious complication of SARS-CoV2 infection in children. Multisystem involvement should be anticipated and promptly treated.

LncRNAs in Kawasaki disease and Henoch-Schönlein purpura: mechanisms and clinical applications

Kawasaki disease (KD) and Henoch-Schönlein purpura (HSP) are the two most predominant types of childhood vasculitis. In childhood vasculitis, factors such as lack of sensitive diagnostic indicators and adverse effects of drug therapy may cause multiorgan system involvement and complications and even death. Many studies suggest that long noncoding RNAs (lncRNAs) are involved in the mechanism of vasculitis development in children and can be used to diagnose or predict prognosis by lncRNAs. In existing drug therapies, lncRNAs are also involved in drug-mediated treatment mechanisms and are expected to improve drug toxicity. The aim of this review is to summarize the link between lncRNAs and the pathogenesis of KD and HSP. In addition, we review the potential applications of lncRNAs in multiple dimensions, such as diagnosis, treatment, and prognosis prediction. This review highlights that targeting lncRNAs may be a novel therapeutic strategy to improve and treat KD and HSP.

Diagnostic value of D-dimer in differentiating multisystem inflammatory syndrome in Children (MIS-C) from Kawasaki disease: systematic literature review and meta-analysis

Coronavirus disease 2019 (COVID-19) is frequently associated with thrombo inflammation, which can predispose to developing of life-threatening conditions in children such as the multisystem inflammatory syndrome (MIS-C) and Kawasaki disease. Because of the consistent overlap in pathogenesis and symptoms, identifying laboratory tests that may aid in the differential diagnosis of these pathologies becomes crucial. We performed an electronic search in PubMed, Web of Science and Scopus, without date or language restrictions, to identify all possible studies reporting D-dimer values in separate cohorts of children with MIS-C or Kawasaki disease. Three multicenter cohort studies were included in our analysis, totaling 487 patients (270 with MIS-C and 217 with Kawasaki disease). In this meta-analysis, significantly higher D-dimer values were found in MIS-C compared to Kawasaki disease in all three studies, yielding an SMD of 1.5 (95 % CI, 1.3-1.7) mg/L. Thus, very high D-dimer values early in the course of disease should raise the clinical suspicion of MIS-C rather than Kawasaki disease. Further studies should be planned to identify harmonized D-dimer diagnostic thresholds that may help discriminate these conditions.

Severity predictors for multisystemic inflammatory syndrome in children after SARS-CoV-2 infection in Vietnam

Multisystemic inflammatory syndrome in children (MIS-C) might manifest in a broad spectrum of clinical scenarios, ranging from mild features to multi-organ dysfunction and mortality. However, this novel entity has a heterogenicity of data regarding prognostic factors associated with severe outcomes. The present study aimed to identify independent predictors for severity by using multivariate regression models. A total of 391 patients (255 boys and 136 girls) were admitted to Vietnam National Children's Hospital from January 2022 to June 2023. The median age was 85 (range: 2-188) months, and only 12 (3.1%) patients had comorbidities. 161 (41.2%) patients required PICU admission, and the median PICU LOS was 4 (2-7) days. We observed independent factors related to PICU admission, including CRP ≥ 50 (mg/L) (OR 2.52, 95% CI 1.39-4.56, p = 0.002), albumin ≤ 30 (g/L) (OR 3.18, 95% CI 1.63-6.02, p = 0.001), absolute lymphocyte count ≤ 2 (× 109/L) (OR 2.18, 95% CI 1.29-3.71, p = 0.004), ferritin ≥ 300 (ng/mL) (OR 2.35, 95% CI 1.38-4.01), p = 0.002), and LVEF < 60 (%) (OR 2.48, 95% CI 1.28-4.78, p = 0.007). Shock developed in 140 (35.8%) patients, especially for those decreased absolute lymphocyte ≤ 2 (× 109/L) (OR 2.48, 95% CI 1.10-5.61, p = 0.029), albumin ≤ 30 (g/L) (OR 2.53, 95% CI 1.22-5.24, p = 0.013), or LVEF < 60 (%) (OR 2.24, 95% CI 1.12-4.51, p = 0.022). In conclusion, our study emphasized that absolute lymphocyte count, serum albumin, CRP, and LVEF were independent predictors for MIS-C severity. Further well-designed investigations are required to validate their efficacy in predicting MIS-C severe cases, especially compared to other parameters. As MIS-C is a new entity and severe courses may progress aggressively, identifying high-risk patients optimizes clinicians' follow-up and management to improve disease outcomes.

Elevated risk for psychiatric outcomes in pediatric patients with Multisystem Inflammatory Syndrome (MIS-C): A review of neuroinflammatory and psychosocial stressors

Multisystem Inflammatory Syndrome in Children (MIS-C) is a secondary immune manifestation of COVID-19 involving multiple organ systems in the body, resulting in fever, skin rash, abdominal pain, nausea, shock, and cardiac dysfunction that often lead to hospitalization. Although many of these symptoms resolve following anti-inflammatory treatment, the long-term neurological and psychiatric sequelae of MIS-C are unknown. In this review, we will summarize two domains of the MIS-C disease course, 1) Neuroinflammation in the MIS-C brain and 2) Psychosocial disruptions resulting from stress and hospitalization. In both domains, we present existing clinical findings and hypothesize potential connections to psychiatric outcomes. This is the first review to conceptualize a holistic framework of psychiatric risk in MIS-C patients that includes neuroinflammatory and psychosocial risk factors. As cases of severe COVID-19 and MIS-C subside, it is important for clinicians to monitor outcomes in this vulnerable patient population.

Clinical and Laboratory Biomarkers as Predictors of Severity in Pediatric Inflammatory Multisystem Syndrome-temporally Associated With SARS-CoV-2: Data From a Prospective Nationwide Surveillance Study in Switzerland

BACKGROUND

PIMS-TS (pediatric inflammatory multisystem syndrome-temporally associated with SARS-CoV-2) is a rare but serious condition in children following SARS-CoV-2 infection, characterized by a range of clinical symptoms with varying severity. Understanding risk factors for severe PIMS-TS is crucial for appropriate and timely intervention.

OBJECTIVE

To identify factors associated with increased PIMS-TS severity in children.

METHODS

In this nationwide prospective observational study, epidemiological and clinical data was collected from children <18 years of age with suspected or confirmed PIMS-TS from all 29 pediatric hospitals in Switzerland. Children were categorized into 3 groups according to admission to intensive care unit (ICU): non-ICU, ICU-moderate and ICU-severe, defined as requirement of invasive ventilation and/or inotropic support.

RESULTS

A total of 204 children were included; 99 (49%) were categorized as non-ICU, 50 (25%) as ICU-moderate and 55 (27%) as ICU-severe. In ICU-severe cases, respiratory and neurological symptoms were more frequent compared with non-ICU cases: 72% versus 47%, P < 0.001 and 66% versus 41%, P = 0.001, respectively. Compared with the non-ICU group, children in the ICU-severe group had lower lymphocyte counts, higher neutrophil-lymphocyte ratios, lower platelet counts, as well as higher C-reactive protein, N-terminal pro-B-type natriuretic peptide, troponin T and creatinine levels at admission. Lymphopenia and elevated troponin T levels at admission were associated with an increased risk of being in the ICU-severe group.

CONCLUSION

The severity of PIMS-TS may be predicted using clinical symptoms and laboratory biomarkers, which help clinicians in decision-making and management of patients.

One- and Two-Year Multidisciplinary Follow-Up of MIS-C at a Tertiary Hospital: A Retrospective Cohort Study

BACKGROUND

Although 6-month follow-up of patients with multisystem inflammatory syndrome in children (MIS-C) was reassuring, there is scant data on long-term sequelae, including whether changing variants affect clinical severity and outcomes.

METHODS

Children (<18 years of age) admitted to Great Ormond Street Hospital between April 4, 2020, and January 2023, meeting diagnostic criteria for MIS-C were included. Admission and follow-up data were categorized by the predominant SARS-CoV-2 circulating variant in the United Kingdom.

RESULTS

One hundred and sixty children [median age, 10.1 (interquartile range, 7.9-12.6) years] were included. There was no difference in the time of symptom onset to diagnosis between waves (P=0.23) or hospitalization days across all waves (P=0.32). Inflammatory markers were normal for up to 2 years in all patients except one. Eleven patients (6.9%) remain in follow-up: cardiology (n=5), gastroenterology (n=5) and nephrology (n=1). The main self-reported symptoms at 2 years were abdominal pain (n=5) and myalgia (n=2). Fatigue was present in approximately a quarter of patients at admission; this reduced to 14 (9%), (2%) and 1 (2%) at 6-month, 1-year and 2-year follow-ups, respectively. Chronic fatigue or long-COVID symptomatology was rare (n=1) even with high rates of concurrent Epstein-Barr virus positivity (49/134). All patients had sustained neurological recovery with no new neurological pathology observed.

CONCLUSIONS

Patients with MIS-C have a sustained recovery, which is reassuring for positive long-term outcomes. Across waves, time from symptom onset to diagnosis and treatment, symptomatology and length of stay were similar. Sustained recovery is reassuring for clinicians and parents alike. Differentiating long-COVID symptomatology from that of MIS-C is important in formulating an individualized treatment plan.

Clinical presentation, diagnosis and management of multisystem inflammatory syndrome in children (MIS-C): a systematic review

BACKGROUND

Knowledge about multisystem inflammatory syndrome in children (MIS-C) is evolving, and evidence-based standardised diagnostic and management protocols are lacking. Our review aims to summarise the clinical and diagnostic features, management strategies and outcomes of MIS-C and evaluate the variances in disease parameters and outcomes between high-income countries (HIC) and middle-income countries (MIC).

METHODS

We searched four databases from December 2019 to March 2023. Observational studies with a sample size of 10 or more patients were included. Mean and prevalence ratios for various variables were pooled by random effects model using R. A mixed generalised linear model was employed to account for the heterogeneity, and publication bias was assessed via funnel and Doi plots. The primary outcome was pooled mean mortality among patients with MIS-C. Subgroup analysis was conducted based on the income status of the country of study.

RESULTS

A total of 120 studies (20 881 cases) were included in the review. The most common clinical presentations were fever (99%; 95% CI 99.6% to 100%), gastrointestinal symptoms (76.7%; 95% CI 73.1% to 79.9%) and dermatological symptoms (63.3%; 95% CI 58.7% to 67.7%). Laboratory investigations suggested raised inflammatory, coagulation and cardiac markers. The most common management strategies were intravenous immunoglobulins (87.5%; 95% CI 82.9% to 91%) and steroids (74.7%; 95% CI 68.7% to 79.9%). Around 53.1% (95% CI 47.3% to 58.9%) required paediatric intensive care unit admissions, and overall mortality was 3.9% (95% CI 2.7% to 5.6%). Patients in MIC were younger, had a higher frequency of respiratory distress and evidence of cardiac dysfunction, with a longer hospital and intensive care unit stay and had a higher mortality rate than patients in HIC.

CONCLUSION

MIS-C is a severe multisystem disease with better mortality outcomes in HIC as compared with MIC. The findings emphasise the need for standardised protocols and further research to optimise patient care and address disparities between HIC and MIC.

PROSPERO REGISTRATION NUMBER

CRD42020195823.

Longitudinal Cardiac Evaluation of Children with Multisystem Inflammatory Syndrome (MIS-C) Following COVID-19 by Conventional and Speckle-Tracking Echocardiography

Multisystem inflammatory syndrome in children (MIS-C), is a rare but severe, hyperinflammatory complication of COVID-19, in which cardiovascular abnormalities are frequently detected. In this prospective study, we describe the echocardiographic findings in patients with MIS-C, with the use of conventional Echocardiography and Speckle-Tracking Echocardiography (STE) with Left Ventricular (LV) Global Longitudinal Strain (GLS) analysis, in the acute and follow-up phase. In total, 25 MIS-C patients [64% females, mean (± SD) age: 8.3 (± 3.72) years] were included. In the acute phase, median (IQR) Troponin and NT-proBNP and mean heart rate, were 8.07 (14.52) pg/mL, 2875.00 (7713.00) pg/mL, and 102.87 (± 22.96) bpm, respectively. Median (IQR) LV Ejection Fraction (LVEF) was 66 (8)% and LVEF impairment was detected in 2/25 (8%) patients. On follow-up (mean time interval:9.50 ± 4.59 months), heart rate was significantly lower, with a mean value of 90.00 (± 14.56) bpm (p-value = 0.017). Median (IQR) LVEF was 66.00 (6.70)% (p-value = 0.345) and all 25 participants had normal LVEF. In 14/25 patients, additional LV-GLS analysis was performed. During the acute phase, mean LV-GLS was - 18.02 (± 4.40)%. LV-GLS was abnormal in 6/14 patients (42.9%) and among them, only one patient had reduced LVEF. On follow-up (median (IQR) time interval:6.93 (3.66) months), mean LV-GLS was -20.31 (± 1.91)% (p-value = 0.07) and in 1/14 patient (7.1%), the LV-GLS impairment persisted. In conclusion, in the acute and follow-up phase, we detected abnormal LV-GLS values in some patients, in the presence of normal LVEF, indicating that STE-GLS is a valuable tool for identifying subclinical myocardial injury in MIS-C.

Multisystem inflammatory syndrome in children: an Umbrella review

We conducted an Umbrella review of eligible studies to evaluate what patient features have been investigated in the multisystem inflammatory syndrome in children (MIS-C) population, in order to guide future investigations. We comprehensively searched MEDLINE, EMBASE, and Cochrane Database of Systematic Reviews from December 1, 2019 to the May 6, 2022. The time period was limited to cover the coronavirus disease-2019 (COVID-19) pandemic period. The protocol was registered in the PROSPERO registry (CRD42022340228). Eligible studies included (1) a study population of pediatric patients ≤21 years of age diagnosed with MIS-C; (2) an original Systematic review or Mata-analysis; (3) published 2020 afterward; and (4) was published in English. A total of 41 studies met inclusion criteria and underwent qualitative analysis. 28 studies reported outcome data of MIS-C. 22 studies selected clinical features of MIS-C, and 6 studies chose demographic data as a main topic. The mortality rate for children with MIS-C was 1.9% (interquartile range (IQR) 0.48), the ICU admission rate was 72.6% (IQR 8.3), and the extracorporeal membrane oxygenation rate was 4.7% (IQR 2.0). A meta-analysis of eligible studies found that cerebral natriuretic peptide in children with MIS-C was higher than that in children with COVID-19, and that the use of intravenous immunoglobulin (IVIG) in combination with glucocorticoids to treat MIS-C compared to IVIG alone was associated with lower treatment failure. In the future, for patients with MIS-C, studies focused on safety of surgery requiring general anesthesia, risk factors, treatment, and long-term outcomes are warranted.

Programmed Cell Death Protein-1 Regulation in Response to SARS-CoV-2 in Paediatric Multisystem Inflammatory Syndrome Temporally Associated with SARS-CoV-2: A Prospective Cohort Study

The role of programmed death cell protein 1 (PD-1) has already been described in a range of various diseases, including COVID-19. This study provides new, innovative data, related to the expression of PD-1 and the risk of Paediatric Inflammatory Multisystem Syndrome, temporally associated with SARS-CoV-2 infection (PIMS-TS)-a rare, but potentially life-threatening complication of COVID-19. In this study, we evaluated the expression of PD-1 protein in patients with PIMS. Blood samples were taken from patients at the time of diagnosis (n = 33), after 6 weeks (n = 33), 3 months (n = 24), 6 months (n = 24) and 12 months (n = 8). The immunophenotypes were evaluated in flow cytometry. The control group consisted of 35 healthy children with negative SARS-CoV-2 antigen/PCR test, who were asymptomatic and had no history of allergic, autoimmune or oncological diseases. The associations between immunophenotypes, biochemical findings and clinical data were analysed. Significant increases in the expression of PD-1 for CD4+ and CD8+ T cells, compared to the control group, were observed in the day of admission, with a gradual decrease during the first weeks from initiation of treatment. This study sheds new light on the pathogenesis of PIMS-TS, emphasizing the role of PD-1 protein. Future research is essential for early risk prediction in SARS-CoV-2 patients and for devising effective clinical prevention and management strategies.

COVID-19 admissions: Trying to define the real impact of infection in hospitalized patients

INTRODUCTION AND OBJECTIVE

Several studies have suggested that the hospitalization rate for COVID-19 in children and adolescents may reflect the prevalence of the infection rather than the severity of the disease. The aim of this study was to describe the clinical features of hospitalised paediatric patients with SARS-CoV-2 infection in order to understand if the infection was the reason for admission.

METHODS

Retrospective cohort study including patients aged 0-18 years with SARS-CoV-2 infection or multisystem inflammatory syndrome in children (MIS-C) admitted to a tertiary care children's hospital in Spain between 01/01/2020 and 12/31/2021.

RESULTS

228 patients were included, corresponding to 150 cases of COVID-related admission (SARS-CoV-2 infection as main cause of hospitalization) and 78 of non-COVID-related admission (SARS-CoV-2 infection unrelated to the hospitalization). In the group of COVID-related admissions, 58 patients had comorbidities. Forty-nine patients had acute respiratory disease (pneumonia, bronchospasm or bronchiolitis). Multisystem inflammatory syndrome in children was diagnosed in 27 and was significantly more frequent in the first year of the pandemic (wild type virus). Eighty percent of patients with acute respiratory disease needed respiratory support, mostly low-flow oxygen therapy. The severity of the disease was similar in all virus variants. Two patients (both with severe comorbidities) died from COVID-related conditions.

CONCLUSIONS

In our study, one third of the patients were admitted with SARS-CoV-2 infection but not because of it. Acute respiratory disease was less frequent and had a better prognosis compared to the adult population, while MIS-C was a major cause of morbidity and hospitalization. The fatality rate was extremely low.

The plasma proteome differentiates the multisystem inflammatory syndrome in children (MIS-C) from children with SARS-CoV-2 negative sepsis

BACKGROUND

The Multi-System Inflammatory Syndrome in Children (MIS-C) can develop several weeks after SARS-CoV-2 infection and requires a distinct treatment protocol. Distinguishing MIS-C from SARS-CoV-2 negative sepsis (SCNS) patients is important to quickly institute the correct therapies. We performed targeted proteomics and machine learning analysis to identify novel plasma proteins of MIS-C for early disease recognition.

METHODS

A case-control study comparing the expression of 2,870 unique blood proteins in MIS-C versus SCNS patients, measured using proximity extension assays. The 2,870 proteins were reduced in number with either feature selection alone or with a prior COMBAT-Seq batch effect adjustment. The leading proteins were correlated with demographic and clinical variables. Organ system and cell type expression patterns were analyzed with Natural Language Processing (NLP).

RESULTS

The cohorts were well-balanced for age and sex. Of the 2,870 unique blood proteins, 58 proteins were identified with feature selection (FDR-adjusted P < 0.005, P < 0.0001; accuracy = 0.96, AUC = 1.00, F1 = 0.95), and 15 proteins were identified with a COMBAT-Seq batch effect adjusted feature selection (FDR-adjusted P < 0.05, P < 0.0001; accuracy = 0.92, AUC = 1.00, F1 = 0.89). All of the latter 15 proteins were present in the former 58-protein model. Several proteins were correlated with illness severity scores, length of stay, and interventions (LTA4H, PTN, PPBP, and EGF; P < 0.001). NLP analysis highlighted the multi-system nature of MIS-C, with the 58-protein set expressed in all organ systems; the highest levels of expression were found in the digestive system. The cell types most involved included leukocytes not yet determined, lymphocytes, macrophages, and platelets.

CONCLUSIONS

The plasma proteome of MIS-C patients was distinct from that of SCNS. The key proteins demonstrated expression in all organ systems and most cell types. The unique proteomic signature identified in MIS-C patients could aid future diagnostic and therapeutic advancements, as well as predict hospital length of stays, interventions, and mortality risks.

Impact of COVID-19 on Pediatric Inflammatory Bowel Diseases-From Expectations to Reality

Viral infections have always been considered a threat to global health, with numerous outbreaks across time. Despite the relative recent experience with coronavirus-associated diseases such as severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS), severe acute respiratory syndrome-2's (SARS-CoV-2) continuous evolution displays a different behavior. With a tropism for both respiratory and digestive mucosa, coronavirus disease 2019 (COVID-19) and inflammatory bowel disease (IBD) seem to share a particular common background. Current literature offers evidence that viral alteration of the immune system, inflammatory intestinal tissue damage, increased intestinal permeability, incomplete viral clearance with viral antigen persistence, and intestinal dysbiosis, might explain SARS-CoV-2-IBD relationship in terms of etiopathogenesis and evolution. The hyperinflammatory state that both entities have in common explains the lack of success of current IBD therapy, raising the need for new personalized therapeutic options, with better outcomes for IBD and COVID-19 as well. This review aims to summarize the current available data on pediatric IBD evolution, management, and outcomes in the post-COVID period, with an emphasis on the particular aspects of the SARS-CoV-2-IBD relationship in children.

Treatment of multisystem inflammatory syndrome in children

BACKGROUND

Multisystem inflammatory syndrome in children (MIS-C), a relatively uncommon but severe pediatric complication, is associated with coronavirus disease 2019 (COVID-19). A variety of treatment approaches, including intravenous immunoglobulins (IVIGs), glucocorticoids (GCs) and biologic agents, such as anakinra and infliximab, have been described for the management of COVID-19-related MIS-C. Anticoagulant therapy is also important. However, a well-developed treatment system has not been established, and many issues remain controversial. Several recently published articles related to the treatment of MIS-C have been released. Hence, in this review, we identified relevant articles published recently and summarized the treatment of MIS-C more comprehensively and systematically.

DATA SOURCES

We reviewed the literature on the treatment of MIS-C through 20 September 2023. The PubMed/Medline, Web of Science, EMBASE, and Cochrane Library databases were searched with the combination of the terms "multisystem inflammatory syndrome", "MIS-C", "PIMS-TS", "therapy", "treatment", "drug", "IVIG", "GCs", "intravenous immunoglobulin", "corticosteroids", "biological agent", and "aspirin".

RESULTS

The severity of MIS-C varies, and different treatment schemes should be used according to the specific condition. Ongoing research and data collection are vital to better understand the pathophysiology and optimal management of MIS-C.

CONCLUSIONS

MIS-C is a disease involving multiple systems and has great heterogeneity. With the accumulation of additional experience, we have garnered fresh insights into its treatment strategies. However, there remains a critical need for greater standardization in treatment protocols, alongside the pressing necessity for more robust and meticulously conducted studies to deepen our understanding of these protocols. Supplementary file1 (MP4 208044 kb).

The evaluation of the burden of multisystem inflammatory syndrome in children on health economics

Objectives

This study aimed to evaluate the diagnostic tests and treatments applied in patients with multisystem inflammatory syndrome in children (MIS-C) and to determine the effect of the disease on health costs.

Patients and methods

This retrospective cohort study included 59 MIS-C patients (40 males, 19 females; mean age: 7.7±4.2 years; range, 4 months to 16.5 years) who were admitted and treated between April 1, 2020, and November 1, 2021. Demographic and clinical features with hospital costs and length of stay were retrospectively reviewed from the medical files and computerized system of the hospital. Direct medical care costs of items were calculated with the hospital perspective using a combination of microcosting technique (resource-based accounting method) and hospital list data. Cases were classified as mild, moderate, or severe, and the patients were divided into two groups: the mild group and the moderate-severe group. Classification was determined by the vasoactive inotropic score (VIS), degree of respiratory support, and evidence of organ damage.

Results

The mean age of the cases in the mild group was 6.5±3.7 years, and the mean age of the cases in the moderate-severe group was 9.2±4.3 years. Of 59 patients, 19 (32.2%) were followed up in the pediatric intensive care unit. The median duration of hospitalization in the hospital was 8 (interquartile range: 7-12) days. The total cost of the patients hospitalized with the diagnosis of MIS-C during the study period was 849,242.93$, and the mean cost per patient was 14,393.94±9,631.92$. In the distribution of the total cost of hospitalization according to expenses, the highest rate was pharmacy and blood products (51.99%) and IVIG costs (43.99%). While the mean total cost per person was 13,682.87±8,799.63$ in mild cases, it was 16,433.82±9,440.02$ in moderate-severe cases, and no statistically significant relationship was found between the two groups (p>0.05). There was no difference in the mean cost per patient between the cases with and without heart, lung, kidney, or neurologic involvement and advanced respiratory support (p>0.05). There was a strong positive correlation between the total costs and age (r=0.883, n=59, p<0.0001), with increased amount of costs with increased age.

Conclusion

In the study, no statistically significant correlation was found between the total cost of per person in the mild group and the moderate-severe group (p>0.05). This finding may be due to the wide use of IVIG in MIS-C treatment, in addition to low transfer rates to pediatric intensive care units due to high-flow nasal cannula usage.

Postacute Sequelae of SARS-CoV-2 in Children

The coronavirus disease 2019 (COVID-19) pandemic has caused significant medical, social, and economic impacts globally, both in the short and long term. Although most individuals recover within a few days or weeks from an acute infection, some experience longer lasting effects. Data regarding the postacute sequelae of severe acute respiratory syndrome coronavirus 2 infection (PASC) in children, or long COVID, are only just emerging in the literature. These symptoms and conditions may reflect persistent symptoms from acute infection (eg, cough, headaches, fatigue, and loss of taste and smell), new symptoms like dizziness, or exacerbation of underlying conditions. Children may develop conditions de novo, including postural orthostatic tachycardia syndrome, myalgic encephalomyelitis/chronic fatigue syndrome, autoimmune conditions and multisystem inflammatory syndrome in children. This state-of-the-art narrative review provides a summary of our current knowledge about PASC in children, including prevalence, epidemiology, risk factors, clinical characteristics, underlying mechanisms, and functional outcomes, as well as a conceptual framework for PASC based on the current National Institutes of Health definition. We highlight the pediatric components of the National Institutes of Health-funded Researching COVID to Enhance Recovery Initiative, which seeks to characterize the natural history, mechanisms, and long-term health effects of PASC in children and young adults to inform future treatment and prevention efforts. These initiatives include electronic health record cohorts, which offer rapid assessments at scale with geographical and demographic diversity, as well as longitudinal prospective observational cohorts, to estimate disease burden, illness trajectory, pathobiology, and clinical manifestations and outcomes.

COVID-19 Associated Cardiovascular Disease-Risks, Prevention and Management: Heart at Risk Due to COVID-19

The SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus-2) virus and the resulting COVID-19 pandemic have had devastating and lasting impact on the global population. Although the main target of the disease is the respiratory tract, clinical outcomes, and research have also shown significant effects of infection on other organ systems. Of interest in this review is the effect of the virus on the cardiovascular system. Complications, including hyperinflammatory syndrome, myocarditis, and cardiac failure, have been documented in the context of COVID-19 infection. These complications ultimately contribute to worse patient outcomes, especially in patients with pre-existing conditions such as hypertension, diabetes, or cardiovascular disease (CVD). Importantly and interestingly, reports have demonstrated that COVID-19 also causes myocardial injury in adults without pre-existing conditions and contributes to systemic complications in pediatric populations, such as the development of multisystem inflammatory syndrome in children (MIS-C). Although there is still a debate over the exact mechanisms by which such complications arise, understanding the potential paths by which the virus can influence the cardiovascular system to create an inflammatory environment may clarify how SARS-CoV-2 interacts with human physiology. In addition to describing the mechanisms of disease propagation and patient presentation, this review discusses the diagnostic findings and treatment strategies and the evolution of management for patients presenting with cardiovascular complications, focusing on disease treatment and prevention.

Cardiac Involvement in Patients With Multisystem Inflammatory Syndrome in Adults

Multisystemic inflammatory syndrome in adults is a hyperinflammatory condition following (within 4-12 weeks) SARS-CoV-2 infection. Here, the dysregulation of the immune system leads to a multiorgan involvement often affecting the heart. Cardiac involvement in multisystemic inflammatory syndrome in adults has been described mainly in young men without other comorbidities and may present with different clinical scenarios, including acute heart failure, life-threatening arrhythmias, pericarditis, and myocarditis, with a nonnegligible risk of mortality (up to 7% of all cases). The heterogeneity of its clinical features and the absence of a clear case definition make the differential diagnosis with other postinfectious (eg, infective myocarditis) and hyperinflammatory diseases (eg, adult Still disease and macrophage activation syndrome) challenging. Moreover, the evidence on the efficacy of specific treatments targeting the hyperinflammatory response underlying this clinical condition (eg, glucocorticoids, immunoglobulins, and other immunomodulatory agents) is sparse and not supported by randomized clinical trials. In this review article, we aim to provide an overview of the clinical features and the diagnostic workup of multisystemic inflammatory syndrome in adults with cardiac involvement, highlighting the possible pathogenetic mechanisms and the therapeutic management, along with remaining knowledge gaps in this field.

Unveiling the intricacies of COVID-19: Autoimmunity, multi-organ manifestations and the role of autoantibodies

COVID-19 is a severe infectious disease caused by a SARS-CoV-2 infection. It has caused a global pandemic and can lead to acute respiratory distress syndrome (ARDS). Beyond the respiratory system, the disease manifests in multiple organs, producing a spectrum of clinical symptoms. A pivotal factor in the disease's progression is autoimmunity, which intensifies its severity and contributes to multi-organ injuries. The intricate interaction between the virus' spike protein and human proteins may engender the generation of autoreactive antibodies through molecular mimicry. This can further convolute the immune response, with the potential to escalate into overt autoimmunity. There is also emerging evidence to suggest that COVID-19 vaccinations might elicit analogous autoimmune responses. Advanced technologies have pinpointed self-reactive antibodies that target diverse organs or immune-modulatory proteins. The interplay between autoantibody levels and multi-organ manifestations underscores the importance of regular monitoring of serum antibodies and proinflammatory markers. A combination of immunosuppressive treatments and antiviral therapy is crucial for managing COVID-19-associated autoimmune diseases. The review will focus on the generation of autoantibodies in the context of COVID-19 and their impact on organ health.

High Fatality Rates in Pediatric Multisystem Inflammatory Syndrome: A Multicenter Experience From the Epicenter of Brazil's Coronavirus Pandemic

BACKGROUND

Brazil´s case fatality rate (CFR) of pediatric multisystem inflammatory syndrome in children and adolescents (MIS-C) is among the highest worldwide. Despite these concerns, limited hospital-based and comprehensive pediatric data have been published on MIS-C in Brazilian children.

METHODS

We performed a descriptive analysis of the MIS-C scores in 16 public and private hospitals providing secondary and tertiary care in the metropolitan area of São Paulo, Brazil. Clinical and demographic information were systematically extracted from the electronic medical records of each patient. Logistic regression analysis was performed to identify the combined effects of MIS-C phenotype, disease severity and comorbidity as dependent variables.

RESULTS

A total of 101 patients met the MIS-C criteria and were evaluated. The median age was 67 months, 60% were male, 28.7% were black or afrodescendant and 62.3% were admitted to public hospitals. Underlying medical conditions were observed in 16.8% of patients and were associated with a longer duration of hospitalization. A Kawasaki disease-like phenotype was observed in 43.5% of patients, and they demonstrated a trend of lower median age. Children with severe MIS-C were older (median age 91 months vs. 36 months) and had a nonspecific phenotype, more cardiovascular and respiratory involvement and kidney injury; 73.3% required intensive care, 20.8% required mechanical ventilation and 35.6% required inotropic support. Four deaths occurred (CFR = 3.9%), three of which were in healthy participants.

CONCLUSION

We identified a lower median age, particularly among children with Kawasaki disease-like phenotypes, those with a significant need for intensive care, and a high CFR in MIS-C. Our findings confirmed the increased severity of the disease in the selected Brazilian population.

Using HScore for Evaluation of Hemophagocytosis in Multisystem Inflammatory Syndrome Associated with COVID-19 in Children

Hemophagocytic syndrome is a key point in the pathogenesis of severe forms of multisystem inflammatory syndrome associated with COVID-19 in children (MIS-C). The factors associated with hemophagocytosis in patients with MIS-C were assessed in the present study of 94 boys and 64 girls ranging in age from 4 months to 17 years, each of whose HScore was calculated. In accordance with a previous analysis, patients with HScore ≤ 91 (n = 79) and HScore > 91 (n = 79) were compared. Patients with HScore > 91 had a higher frequency of symptoms such as cervical lymphadenopathy, dry cracked lips, bright mucous, erythema/swelling of hands and feet, peeling of fingers, edematous syndrome, hepatomegaly, splenomegaly, and hypotension/shock. They also had a higher erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and D-dimer levels, and a tendency to anemia, thrombocytopenia, and hypofibrinogenemia. They more often needed acetylsalicylic acid and biological treatment and were admitted to ICU in 70.9% of cases. Conclusion: The following signs of severe MIS-C were associated with HScore > 91: myocardial involvement, pericarditis, hypotension/shock, and ICU admission.

Comparative immunogenicity and safety of SpikoGen®, a recombinant SARS-CoV-2 spike protein vaccine in children and young adults: An immuno-bridging clinical trial

BACKGROUND

SpikoGen® is a recombinant subunit spike protein ectodomain vaccine manufactured in insect cells and formulated with the novel polysaccharide-based Advax-CpG55.2 adjuvant. This study aimed to compare the immunogenicity and safety of SpikoGen® vaccine in children, adolescents and young adults.

METHODS

This was a non-randomized, three-arm, open-label, parallel-group, immuno-bridging, non-inferiority trial to compare the immunogenicity and safety of a primary course of two intramuscular doses of SpikoGen® vaccine in children aged 5 to < 12 years, adolescents aged 12 to < 18 years and young adults aged 18 to 40 years. Children 5-12 years received a half dose of 12.5 μg spike protein, whereas the other groups received the full vaccine dose. Vaccine immunogenicity was evaluated via assessment of serum anti-spike and neutralizing antibodies 14 days after the second dose. Solicited adverse events were recorded for 7 days after each vaccination. Safety assessments including serious adverse events were continued through six months after the second dose in children and adolescents.

RESULTS

Two weeks after the second dose, seroconversion rates for neutralizing antibody levels were not significantly different for children (59.50 %), adolescents (52.06 %) and adults (56.01 %). The 95 % confidence interval of the difference in seroconversion rates between children and adults was within the prespecified non-inferiority margin of 10 % (-12 % to 5 %). SpikoGen® vaccine was well tolerated in all age groups with the most common solicited adverse events being injection site pain and fatigue which were generally transient and mild.

CONCLUSION

SpikoGen® vaccine was shown to be safe, well tolerated and immunogenic in children as young as 5 years of age, with non-inferior responses to those seen in adults. The Iranian FDA authorisation of SpikoGen® vaccine is now extended down to 5 years of age.

[Multisystem inflammatory syndrome in children in the context of coronavirus disease 2019 pandemic]

Multisystem inflammatory syndrome in children (MIS-C) is a complex syndrome characterized by multi-organ involvement that has emerged in the context of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak. The clinical presentation of MIS-C is similar to Kawasaki disease but predominantly presents with fever and gastrointestinal symptoms, and severe cases can involve toxic shock and cardiac dysfunction. Epidemiological findings indicate that the majority of MIS-C patients test positive for SARS-CoV-2 antibodies. The pathogenesis and pathophysiology of MIS-C remain unclear, though immune dysregulation following SARS-CoV-2 infection is considered a major contributing factor. Current treatment approaches for MIS-C primarily involve intravenous immunoglobulin therapy and symptomatic supportive care. This review article provides a comprehensive overview of the definition, epidemiology, pathogenesis, clinical presentation, diagnosis, treatment, and prognosis of MIS-C.

Responses to Common Misconceptions Relating to COVID-19 Variant-Adapted mRNA Vaccines

The evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the waning of immunity over time has necessitated the use of booster doses of original coronavirus disease 2019 (COVID-19) vaccines. This has also led to the development and implementation of variant-adapted messenger RNA (mRNA) vaccines that include an Omicron sub-lineage component in addition to the antigen based on the wild-type virus spike protein. Subsequent emergence of the recombinant XBB sub-lineages triggered the development of monovalent XBB-based variant-adapted mRNA vaccines, which are available for vaccination campaigns in late 2023. Misconceptions about new variant-adapted vaccines may exacerbate vaccine fatigue and drive the lack of vaccine acceptance. This article aims to address common concerns about the development and use of COVID-19 variant-adapted mRNA vaccines that have emerged as SARS-CoV-2 has continued to evolve.

Multisystem inflammatory syndrome in 1.2 million children: longitudinal cohort study of risk factors

BACKGROUND

We identified patient characteristics associated with an increased risk of developing MIS-C.

METHODS

We conducted a longitudinal cohort study of 1,195,327 patients aged 0-19 years between 2006 and 2021, including the first two waves of the pandemic (February 25-August 22, 2020 and August 23, 2020-March 31, 2021). Exposures included prepandemic morbidity, birth outcomes, and family history of maternal disorders. Outcomes included MIS-C, Kawasaki disease, and other Covid-19 complications during the pandemic. We calculated risk ratios (RRs) and 95% confidence intervals (CIs) for the association between patient exposures and these outcomes using log-binomial regression models adjusted for potential confounders.

RESULTS

Among 1,195,327 children, 84 developed MIS-C, 107 Kawasaki disease, and 330 other Covid-19 complications during the first year of the pandemic. Prepandemic hospitalizations for metabolic disorders (RR 11.3, 95% CI 5.61-22.6), atopic conditions (RR 3.34, 95% CI 1.60-6.97), and cancer (RR 8.11, 95% CI 1.13-58.3) were strongly associated with the risk of MIS-C, compared with no exposure. These same exposures were also associated with Kawasaki disease and other Covid-19 complications. However, birth characteristics and history of maternal morbidity were not associated with MIS-C development.

CONCLUSIONS

Children with pre-existing morbidity have a considerably elevated risk of MIS-C.

IMPACT

Morbidities that predispose children to multisystem inflammatory syndrome (MIS-C) are unclear. In this study, prepandemic hospitalizations for metabolic disorders, atopic conditions, and cancer were associated with an elevated risk of MIS-C. Birth characteristics and family history of maternal morbidity were not, however, associated with MIS-C. Pediatric morbidities may play a greater role in MIS-C onset than maternal or perinatal characteristics, and may help clinicians better recognize children at risk for this complication.

Multisystem Inflammatory Syndrome in Children (MIS-C) in a Low-income Country: What Treatment Should be Adopted in Case of a Lack of Immunoglobulin?

INTRODUCTION

In multisystem inflammatory syndrome (MIS-C), children typically present high-grade fever, gastrointestinal symptoms, Kawasaki-like symptoms, and even a toxic shock-like syndrome days to weeks after recovering from SARS-CoV-2 infection. It is important to raise awareness of this condition in order to have early diagnosis and immediate treatment of patients. We have, herein, reported 44 cases of MIS-C with various risk factors and symptoms. Furthermore, we have emphasized the efficacy of experience in treating children with MIS-C with high-dose corticosteroids as an alternative to immunoglobulin in low-income countries.

METHODS

We conducted a targeted survey of MIS-C from early May 2020 to October 2022 on 44 children and adolescents with characteristics of multisystem inflammatory syndrome admitted to the pediatric department of the university hospital center in Oujda, Morocco, to which patients diagnosed with MIS-C were referred. The case definition included six criteria: serious illness leading to hospitalization, age under 18 years, fever of at least 24 hours, laboratory evidence of inflammation, multi-organ involvement, biological inflammatory syndrome, and evidence of coronavirus infection based on polymerase chain reaction, antibody testing or exposure to people with COVID-19 in the past month. The criteria used to diagnose myocarditis were impaired left ventricular function, central mitral leak, and elevation of BNP or pro-BNP. Coronary involvement was assessed by the z-score and the criteria for its presence was a z-score equal to or greater than 2.5.

RESULTS

Our study included 44 children and adolescents with MIS-C in our hospital, with male predominance (79%) and a median age of six years. Cardiovascular involvement was present in 91%, mucocutaneous in 78%, gastrointestinal in 70%, hematologic in 84%, and respiratory in 2% of patients. Coronary abnormalities (z-score ≥ 2.5) were documented in 21 cases (48%). Glucocorticoids were frequently used in comparison to immunoglobulin, which were uncommonly available and expensive.

CONCLUSION

The therapeutic protocol that was adopted was high doses of short-term prednisone (Cortancyl) at 4mg/kg/day for 4 days. Favorable outcome was noted in all patients over a 2-year period.

Cardiovascular Manifestations of Multisystem Inflammatory Syndrome in Children: A Single-Center Bulgarian Study

Background and objectives: Multisystem inflammatory syndrome in children (MIS-C) poses challenges to the healthcare system, especially with frequent heart involvement. The current retrospective observational study aims to summarize the type and degree of cardiovascular involvement in children with MISC and to find possible associations between laboratory, inflammatory, and imaging abnormalities and the predominant clinical phenotype using a cluster analysis. Material and methods: We present a retrospective observational single-center study including 51 children meeting the MIS-C criteria. Results: Fifty-three percent of subjects presented with at least one sign of cardiovascular involvement (i.e., arterial hypotension, heart failure, pericardial effusion, myocardial dysfunction, pericarditis without effusion, myocarditis, coronaritis, palpitations, and ECG abnormalities). Acute pericarditis was found in 30/41 of the children (73%) assessed using imaging: 14/30 (46.7%) with small pericardial effusion and 16/30 (53.3%) without pericardial effusion. The levels of CRP were significantly elevated in the children with pericarditis (21.6 ± 13 mg/dL vs. 13.9 ± 11 mg/dL, p = 0.035), and the serum levels of IL-6 were higher in the children with small pericardial effusion compared to those without (191 ± 53 ng/L vs. 88 ± 27 ng/L, p = 0.041). Pericarditis with detectable pericardial effusion was significantly more frequent in the female vs. male subjects, 72% vs. 30% (p = 0.007). The hierarchical clustering analysis showed two clusters: Cluster 1 includes the children without cardiovascular symptoms, and Cluster 2 generalizes the MIS-C children with mild and severe cardiovascular involvement, combining pericarditis, myocarditis, heart failure, and low blood pressure. Also, subjects from Cluster 2 displayed significantly elevated levels of fibrinogen (5.7 ± 0.3 vs. 4.6 ± 0.3, p = 0.03) and IL-6 (158 ± 36 ng/mL vs. 66 ± 22 ng/mL, p = 0.032), inflammatory markers suggestive of a cytokine storm. Conclusions: Our results confirm that children with oligosymptomatic MIS-C or those suspected of long COVID-19 should be screened for possible cardiological involvement.

Description and outcomes of Afro-Caribbean children treated for multisystem inflammatory syndrome in the French West Indies

Introduction

Several studies have reported a higher frequency and greater morbidity and mortality of multisystem inflammatory syndrome in children (MIS-C) of black African descent.

Objectives

We aimed to describe the clinical, laboratory and echocardiographic characteristics as well as outcomes of children with MIS-C requiring admission to a pediatric intensive care unit (PICU) in the French West Indies (FWI), where the majority of the population is Afro-Caribbean.

Methods

Ambidirectional observational cohort study between April 1, 2020 and August 31, 2022. Children (age ≤18 years) with MIS-C and organ failure were included. Every patient was monitored and treated following the same protocol, with repeated biological tests, echocardiography, intravenous steroids and polyvalent immunoglobulins. The primary outcomes were clinical, laboratory and echocardiography characteristics.

Results

Forty children (median age 7 years, range: 5-11) were included. The majority (77 %) were included prospectively. Thirty-five (87 %) had gastrointestinal symptoms, 30 (75 %) presented initial heart failure (with persisting diastolic dysfunction at day 7) and 18 (45 %) had pericarditis. Sixteen (40 %) were in cardiogenic shock and required inotropic support. Median duration of inotropic support and hospitalization in PICU were respectively 4 and 5 days. The evolution curves of the inflammatory variables matched after treatment. The clinical outcomes were favorable. The Delta variant was associated with the highest incidence of MIS-C.

Conclusion

This is the first description of MIS-C course among children of Afro-Caribbean descent. The outcomes were good, without any death or cardiac sequelae. Our work does not support an ethnic susceptibility for severity of MIS-C in Afro-Caribbean population.

Immunogenicity and Safety of a SARS-CoV-2 Inactivated Vaccine KCONVAC in Chinese Children: Randomized, Double-blind, Placebo-controlled Phase 1 and 2 Trials

BACKGROUND

It is important to extend the indication of severe acute respiratory syndrome coronavirus 2 vaccine to children to improve the vaccine intake rate and reduce infection in this population.

METHODS

In 2 phase 1 and phase 2 randomized, double-blind and placebo-controlled trials, 84 and 480 Chinese healthy children 3 to 17 years old were enrolled, respectively, and randomized in 3:1 ratio to receive 2 doses of a severe acute respiratory syndrome coronavirus 2 inactivated vaccine, KCONVAC or placebo. The 2 doses were given 28 days apart. Adverse events (AEs) were recorded through Day 28 after each dosing. Live virus neutralizing antibody and receptor binding domain antibody (RBD-IgG) were tested before vaccination and after the second dose.

RESULTS

Two doses of the vaccine, KCONVAC, elicited geometric mean titers of 142-150 for neutralizing antibody and 4154-4253 for RBD-IgG 28 days after the second dose. Seroconversion rates were 100% after 2 doses for both antibodies in both trials. The predominant AEs were injection-site pain, cough and fever. Most AEs were grade 1 or 2 in intensity. Five participants reported 6 vaccination-unrelated serious AEs in the phase 2 trial.

CONCLUSIONS

Two doses of this study vaccine, KCONVAC, were well tolerated and immunogenic in children 3 to 17 years of age.

Obesity and Outcomes of Kawasaki Disease and COVID-19-Related Multisystem Inflammatory Syndrome in Children

Importance

Obesity may affect the clinical course of Kawasaki disease (KD) in children and multisystem inflammatory syndrome in children (MIS-C) associated with COVID-19.

Objective

To compare the prevalence of obesity and associations with clinical outcomes in patients with KD or MIS-C.

Design, Setting, and Participants

In this cohort study, analysis of International Kawasaki Disease Registry (IKDR) data on contemporaneous patients was conducted between January 1, 2020, and July 31, 2022 (42 sites, 8 countries). Patients with MIS-C (defined by Centers for Disease Control and Prevention criteria) and patients with KD (defined by American Heart Association criteria) were included. Patients with KD who had evidence of a recent COVID-19 infection or missing or unknown COVID-19 status were excluded.

Main Outcomes and Measures

Patient demographic characteristics, clinical features, disease course, and outcome variables were collected from the IKDR data set. Using body mass index (BMI)/weight z score percentile equivalents, patient weight was categorized as normal weight (BMI <85th percentile), overweight (BMI ≥85th to <95th percentile), and obese (BMI ≥95th percentile). The association between adiposity category and clinical features and outcomes was determined separately for KD and MIS-C patient groups.

Results

Of 1767 children, 338 with KD (median age, 2.5 [IQR, 1.2-5.0] years; 60.4% male) and 1429 with MIS-C (median age, 8.7 [IQR, 5.3-12.4] years; 61.4% male) were contemporaneously included in the study. For patients with MIS-C vs KD, the prevalence of overweight (17.1% vs 11.5%) and obesity (23.7% vs 11.5%) was significantly higher (P < .001), with significantly higher adiposity z scores, even after adjustment for age, sex, and race and ethnicity. For patients with KD, apart from intensive care unit admission rate, adiposity category was not associated with laboratory test features or outcomes. For patients with MIS-C, higher adiposity category was associated with worse laboratory test values and outcomes, including a greater likelihood of shock, intensive care unit admission and inotrope requirement, and increased inflammatory markers, creatinine levels, and alanine aminotransferase levels. Adiposity category was not associated with coronary artery abnormalities for either MIS-C or KD.

Conclusions and Relevance

In this international cohort study, obesity was more prevalent for patients with MIS-C vs KD, and associated with more severe presentation, laboratory test features, and outcomes. These findings suggest that obesity as a comorbid factor should be considered at the clinical presentation in children with MIS-C.

Twice weekly polymerase chain reaction (PCR) surveillance swabs are not as effective as daily antigen testing for containment of severe acute respiratory coronavirus virus 2 (SARS-CoV-2) outbreaks: A modeling study based on real world data from a child and adolescent psychiatry clinic

OBJECTIVE

In the coronavirus disease 2019 (COVID-19) pandemic, child and adolescent psychiatry wards face the risk of severe acute respiratory coronavirus 2 (SARS-CoV-2) introduction and spread within the facility. In this setting, mask and vaccine mandates are hard to enforce, especially for younger children. Surveillance testing may detect infection early and enable mitigation measures to prevent viral spread. We conducted a modeling study to determine the optimal method and frequency of surveillance testing and to analyze the effect of weekly team meetings on transmission dynamics.

DESIGN AND SETTING

Simulation with an agent-based model reflecting ward structure, work processes, and contact networks from a real-world child and adolescent psychiatry clinic with 4 wards, 40 patients, and 72 healthcare workers.

METHODS

We simulated the spread of 2 SARS-CoV-2 variants over 60 days under surveillance testing with polymerase chain reaction (PCR) tests and rapid antigen tests in different scenarios. We measured the size, peak, and the duration of an outbreak. We compared medians and percentage of spillover events to other wards from 1,000 simulations for each setting.

RESULTS

The outbreak size, peak, and duration were dependent on test frequency, test type, SARS-CoV-2 variant, and ward connectivity. Under surveillance conditions, joint staff meetings and therapists shared between wards did not significantly change median outbreak size under surveillance conditions. With daily antigen testing, outbreaks were mostly confined to 1 ward and median outbreak sizes were lower than with twice-weekly PCR testing (1 vs 22; P < .001).

CONCLUSION

Modeling can help to understand transmission patterns and guide local infection control measures.

Cardiac manifestations of MIS-C: cardiac magnetic resonance and speckle-tracking data

Background

Cardiac involvement is central in MIS-C and represents the main cause of morbidity. In this study, we aimed to assess myocardial damage in patients with MIS-C using cardiac magnetic resonance (CMR) during the acute phase, as well as left ventricular and atrial longitudinal strain on admission, at discharge, and after 3 months.

Methods

We performed a single-center prospective cohort study and case-control study. Between September 2020 and February 2022, we enrolled 39 patients hospitalized for MIS-C at our center. We performed left ventricular and atrial longitudinal 2D strain analysis on admission and during follow-up; echocardiographic data were compared to a matched control population. Patients above 4 years old with increased troponin underwent CMR.

Results

Of 24 patients (mean age: 8.2 ± 4.9 years) who underwent CMR, 14 (58%) presented myocardial edema and 6 (25%) late gadolinium enhancement (LGE). LGE was associated with older age (p < 0.01), increased BMI (p = 0.03), increased ferritin levels (p < 0.001), lower left ventricular (LV) ejection fraction (p < 0.001), LV longitudinal strain (p = 0.004), left atrial (LA) strain (p = 0.05), and prolonged hospital stay (p = 0.02). On admission, LV ejection fraction, LV longitudinal strain, and LA strain were impaired, but each improved gradually over time; LVEF was the fastest to recover, while global LV longitudinal strain was still impaired as compared to controls after 3 months (p = 0.01).

Conclusion

Our study demonstrates that myocardial injury is present in a quarter of MIS-C patients, and impaired LA and LV myocardial deformation persist for at least several weeks after the acute phase. CMR and LV/LA strain could help us to individualize follow-up of MIS-C patients.

Subclinical myocardial assessment after BNT162b2 messenger RNA COVID-19 vaccination in adolescents with chronic heart disease: a speckle-tracking echocardiography study

PURPOSE

Case reports of the development of perimyocarditis in adolescents and young adults after BNT162b2 messenger RNA (mRNA) COVID-19 vaccination have raised concerns about the cardiac side effects of the vaccine. The aim of the study was to evaluate clinical follow-up and subclinical myocardial function after mRNA COVID-19 vaccine in adolescents with chronic heart disease.

METHODS

Forty-one adolescents aged 12-18 who were followed up at paediatric cardiology clinic between December 2021 and May 2022, and who had received two doses of the Pfizer-BioNTech COVID-19 mRNA vaccine were included in the study. The patients were evaluated five times in total - before the vaccination, one week after receiving the first dose, one month after receiving the first dose, one week after receiving the second dose, and one month after receiving the second dose. Cardiac assessment for all patients included an electrocardiogram, transthoracic echocardiography, and two-dimensional speckle-tracking strain echocardiography for left ventricular subclinical myocardial function.

RESULTS

The mean age of the adolescents was 16.2 ± 1.5 years, and 56% (n = 23) were male. There was no statistically significant difference in patients' echocardiographic measurements including left ventricular global longitudinal strain and electrocardiogram parameters including PR, QRS, and QTc intervals through the follow-up. Seven patients reported cardiac complaints at post-vaccination follow-up visits, but laboratory and echocardiographic evidence of cardiac involvement was not observed.

CONCLUSIONS

Based on the results of our study, the mRNA COVID-19 vaccine did not cause impairment in subclinical myocardial function assessed by speckle-tracking echocardiography in adolescents with chronic heart disease.

Serological analysis of severe acute respiratory syndrome coronavirus 2 infection in children with Kawasaki disease

Multisystem inflammatory syndrome in children (MIS-C) was reported as a severe complication of coronavirus disease 2019; an infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and was suggested to be associated with Kawasaki disease (KD) in terms of severe systemic inflammation and mucocutaneous symptoms. Because severe gastrointestinal symptoms and systemic shock are more frequently observed with MIS-C, patients with mild MIS-C might have been diagnosed with KD. In this study, titers of IgG antibodies against the SARS-CoV-2 S (S-IgG) and N proteins (N-IgG) were measured in 99 serum samples collected from patients with KD treated between January 2020 and December 2021 to evaluate the relationship between KD and SARS-CoV-2 infection. S-IgG were detected in only one patient out of 99 patients. This patient had coronavirus disease 2019 (COVID-19) 10 months before KD onset, and was unlikely MIS-C. According to characters of S-IgG and N-IgG, the patients was unlikely infected with SARS-CoV-2 just before the onset of KD. In addition to this study, the 26th Nationwide Survey and previous studies showed an association between KD and SARS-CoV-2 to be unlikely. In conclusion, SARS-CoV-2 infection was not observed in patients with KD until Delta predominance in Japan by the method of detecting SARS-CoV-2 IgG.

Multisystem inflammatory syndrome in children (MIS-C) and sepsis differentiation by a clinical and analytical score: MISSEP score

Differential diagnosis between Multisystem Inflammatory Syndrome in Children (MIS-C) and other causes of systemic inflammatory response such as sepsis is complex. The aims were to evaluate the differences between pediatric patients with MIS-C and sepsis and to develop a score to distinguish both entities. This was a retrospective study that compared demographic, clinical, diagnostic, and therapeutic data of pediatric patients with MIS-C (cohort 2020-2022) and sepsis (cohorts 2010-2014 and 2017-2018) admitted to a Pediatric Intensive Care Unit (PICU) of a tertiary care hospital. A diagnostic score was developed with variables that differentiated the two conditions. Twenty-nine patients with MIS-C were identified, who were matched 1:3 with patients with sepsis (n = 87). Patients with MIS-C were older (10 vs. 4 years old), and the majority were male (69%). Clinical characteristics that demonstrated differences were prolonged fever and signs and symptoms affecting skin-mucosa and gastrointestinal system. Leukocytes, PCT, and ferritin were higher in sepsis, while thrombocytopenia, lymphopenia, and elevated fibrinogen and adrenomedullin (biomarker with a role for the detection of invasive infections) were more frequent in MIS-C. MIS-C patients presented greater myocardial dysfunction (p < 0.001). Five criteria were selected and included in the MISSEP score after fitting them into a multivariate logistic regression model: fever > 48 hours (20 points), thrombocytopenia < 150 × 103/µL (6 points), abdominal pain (15 points), conjunctival erythema (11 points), and Vasoactive Inotropic Score (VIS) > 10 (7 points). The cutoff > 25 points allowed to discriminate MIS-C from sepsis with a sensitivity of 0.89 and specificity of 0.95.     Conclusion: MIS-C phenotype overlaps with sepsis. MISSEP score could be useful to distinguish between both entities and direct specific treatment. What is Known: • Differential diagnosis between Multisystem Inflammatory Syndrome in Children (MIS-C) and other causes of systemic inflammatory response such as sepsis is complex. • It is essential to establish an accurate initial diagnosis and early specific treatment in both cases of MIS-C and sepsis to improve the prognosis of these patients. What is New: • Patients with MIS-C are older and have characteristic symptoms of prolonged fever, gastrointestinal symptoms, skin-mucosal involvement, and greater myocardial dysfunction, compared to patients with sepsis. • The use of diagnostic scores, such as the MISSEP score, can be very useful to distinguish between the two entities and help direct specific treatment.

A prospective long-term evaluation of the ocular findings of children followed with the diagnosis of multisystem inflammatory syndrome (long-term evaluation of ocular findings following MIS-C)

BACKGROUND/OBJECTIVES

The most frequently reported ocular finding in the acute phase of the multisystem inflammatory syndrome in children (MIS-C), is conjunctivitis. More rarely, punctuate epitheliopathy, anterior uveitis and optic disc oedema can be seen. We aimed to investigate the acute and long-term ocular effects of MIS-C.

SUBJECTS/METHODS

Cases aged 1 month to 18 years who were diagnosed with MIS-C between January 2022 and June 2022 in the Department of Pediatric Infectious Diseases in our hospital were included in the study. Ophthalmological examinations were performed immediately after diagnosis, at one month, three months, and six months.

RESULTS

Males consisted of 64.7% of the 34 cases included in the study and the mean age was 8.68 ± 4.32 years (min-max:2-17). In the first examination, conjunctivitis was observed in 6 (17.6%), punctuate epitheliopathy in 4 (11.7%), and subconjunctival haemorrhage in 3 (8.8%) patients. Two patients (5.8%) had optic disc oedema. No pathological anterior or posterior segment findings were observed in the sixth-month examination. The relationship between subconjunctival haemorrhage and intensive care hospitalisation was statistically significant (p = 0.014). Also, all patients with subconjunctival haemorrhage were clinically classified as severe MIS-C (p = 0.002).

CONCLUSION

Although pathological ocular findings were observed in the acute phase of the disease, all of them were found to be improved at the sixth-month follow-up. The most striking finding of our study is that cases with subconjunctival haemorrhage were clinically more severe, and all patients needed intensive care. This study may be informative in establishing ocular follow-up protocols that are expected to be carried out in the acute period and in the follow-up of these patients.

[The burden of COVID-19 in a heterogeneous population of immunocompromised patients - realities of the postpandemic]

On July 3, 2023, an interdisciplinary Council of Experts "The burden of COVID-19 in a heterogeneous population of immunocompromised patients - post-pandemic realities" was held in Moscow with leading experts in pulmonology, rheumatology, hematology, oncology, nephrology, allergology-immunology, transplantation, and infectious diseases. The aim of the meeting was to discuss the current clinical and epidemiologic situation related to COVID-19, the relevance of disease prevention strategies for high-risk patients. The experts addressed the following issues: 1) the disease burden of COVID-19 in 2023 for patients with immunodeficiency in different therapeutic areas; 2) the place of passive immunization with monoclonal antibodies as a method of COVID-19 prophylaxis among immunocompromised patients; 3) prerequisites for the inclusion of passive immunization of immunocompromised patients into routine clinical practice.

Severity of SARS-CoV-2 infection in a hospital population: a clinical comparison across age groups

BACKGROUND

Children tend to have milder forms of COVID-19 than adults, however post-acute complications have been observed also in the paediatric population. In this study, we compared COVID-19-related outcomes and long-term complications between paediatric and adult patients infected by SARS-CoV-2.

METHODS

The study is based on individuals enrolled from October 2020 to June 2021 in the DECO COVID-19 multicentre prospective study supported by the Italian Ministry of Health (COVID-2020-12371781). We included individuals with RT-PCR -confirmed SARS-CoV-2 infection, who were evaluated in the emergency department and/or admitted to COVID-dedicated wards. The severity of SARS-CoV-2 infection was compared across age groups (children/adolescents aged < 18 years, young/middle-aged adults aged 18-64 years and older individuals) through the relative risk (RR) of severe COVID-19. Severity was defined by: 1) hospitalization due to COVID-19 and/or 2) need or supplemental oxygen therapy. RR and corresponding 95% confidence intervals were estimated using log-binomial models.

RESULTS

The study included 154 individuals, 84 (54.5%) children/adolescents, 50 (32.5%) young/middle-aged adults and 20 (13%) older adults. Compared to young/middle-aged adults the risk of hospitalization was lower among paediatric patients (RR: 0.49, 95% CI: 0.32-0.75) and higher among older adults (RR: 1.52, 95% CI: 1.12-2.06). The RR of supplemental oxygen was 0.12 (95% CI: 0.05-0.30) among children/adolescents and 1.46 (95% CI: 0.97-2.19) among older adults. Three children developed multisystem inflammatory syndrome (MIS-C), none was admitted to intensive care unit or reported post-acute Covid-19 complications.

CONCLUSIONS

Our study confirms that COVID-19 is less severe in children. MIS-C is a rare yet severe complication of SARS-CoV-2 infection in children and its risk factors are presently unknown.

Similarities and differences between myocarditis following COVID-19 mRNA vaccine and multiple inflammatory syndrome with cardiac involvement in children

Despite the multiple benefits of vaccination, cardiac adverse Events Following COVID-19 Immunization (c-AEFI) have been reported. These events as well as the severe cardiac involvement reported in Multisystem inflammatory syndrome in children (MIS-C) appear more frequent in young adult males. Herein, we firstly report on the inflammatory profiles of patients experiencing c-AEFI in comparison with age, pubertal age and gender matched MIS-C with cardiac involvement. Proteins related to systemic inflammation were found higher in MIS-C compared to c-AEFI, whereas a higher level in proteins related to myocardial injury was found in c-AEFI. In addition, higher levels of DHEAS, DHEA, and cortisone were found in c-AEFI which persisted at follow-up. No anti-heart muscle and anti-endothelial cell antibodies have been detected. Overall current comparative data showed a distinct inflammatory and androgens profile in c-AEFI patients which results to be well restricted on heart and to persist months after the acute event.

New-onset systemic vasculitis following SARS-CoV-2 infection and vaccination: the trigger, phenotype, and outcome

The global health crisis caused by the COVID-19 pandemic overwhelmed the capacity of healthcare systems to cope with the rapidly spreading infection and its associated complications. Among these complications, autoimmune phenomena such as systemic vasculitis emerged as a significant challenge. Both the SARS-CoV-2 virus and the vaccines developed to combat it appeared to induce clinical manifestations resembling various types of systemic vasculitis, affecting large, medium, and small vessels. These virus- or vaccine-induced vasculitides exhibited a distinct natural history and course from de novo vasculitis, as they were more responsive to steroid therapy and some mild cases even resolved spontaneously. Notably, there have been no confirmed cases of SARS-CoV-2 infection or vaccination triggering variable vessel vasculitis like Behcet's disease or Kawasaki disease. IgA vasculitis, which is predominantly a pediatric condition, was more prevalent in adults after COVID-19 infection and they had a favorable outcome with glucocorticoid treatment. The impact of immunosuppression, especially B-cell-depleting agents, on the immunogenicity of the vaccine was evident, but there was no significant increase in the incidence of SARS-CoV-2 infection in these patients compared to the general population. Considering their relatively benign course, these post-COVID or post-vaccine vasculitides seem to be amenable to 0.8 to 1 mg/kg prednisolone or equivalent, which could be gradually tapered. The need for immunosuppression and the duration of steroid therapy should be determined on an individual basis. While the world still reels from the perils of a deadly pandemic, the aftermath continues to haunt. Our narrative review aims to explore the effects of COVID and the vaccine on systemic vasculitis, as well as the effect of disease and immunosuppression on the immunogenicity of the COVID vaccine.

Clinical Presentation and Management of Multisystem Inflammatory Syndrome in Children With COVID-19: A Systematic Review

Multisystem inflammatory syndrome in children (MIS-C) is a relatively new syndrome associated with coronavirus disease 2019 (COVID-19) that is characterized by a severe clinical course compared to pediatric COVID-19. This review aimed to compile the available evidence on the clinical presentation and management of MIS-C in children with COVID-19. During this systematic review, a comprehensive search was performed in the following databases: PubMed, Embase, Medline, Google Scholar, Cochrane, and Scopus, using predetermined search terms, such as Medical Subject Headings (MeSH) and keywords to find relevant studies on the MIS-C. Relevant data were extracted, and the quality of the studies was evaluated using suitable methods. The collected findings were synthesized and discussed in the study. The World Health Organization's (WHO) definition of MIS-C was the most favored due to its precision and inclusiveness. MIS-C primarily affected children aged 6-12 years, with male predominance. MIS-C involves a range of systems, including gastrointestinal, cardiovascular, hematologic, mucocutaneous, and respiratory. Radiographic findings revealed cardiovascular abnormalities, solid visceral organ involvement, and bowel abnormalities, reflecting a systemic inflammatory process. Laboratory investigations unveiled elevated inflammatory markers, neutrophil activation, release of extracellular traps in vessels, elevated procalcitonin, hyponatremia, hypoalbuminemia, low hemoglobin, and thrombocytopenia. The inflammatory markers and autoantibody profiles are essential in differentiating MIS-C from COVID-19. The preferred treatment primarily involves immunomodulatory therapies like intravenous immunoglobulin (IVIG), glucocorticoids, and interleukin-6 or 1RA inhibitors or a combination of those. In severe cases, extracorporeal membrane oxygenation (ECMO) and mechanical ventilation are necessary, leading to reduced mortality and quick recovery. This review found that the average hospital stay was seven days, and most discharged children fully recovered within seven days. MIS-C is a life-threatening post-COVID-19 condition and involves multiple systems due to systemic inflammation, with elevated inflammation markers. Recognition of multisystem involvement is crucial, and prompt identification and multidisciplinary treatment are vital for optimal outcomes.

Multisystem Inflammatory Syndrome in Children (MIS-C) Related to SARS-CoV-2 and 1-Year Follow-up

OBJECTIVE

To study the demographics, clinical profile, management, outcome and 1-y follow-up of children with multisystem inflammatory syndrome in children (MIS-C).

METHODS

This was a retrospective observational study of 54 Children satisfying the WHO MIS-C criteria admitted during the study period.

RESULTS

Fifty-four children were included in the study, median age was 5.5 (IQR 8.75), 68.5% were males. PICU admissions were 77%. Most involved organ was gastrointestinal (92%), followed by cardiovascular 85%, central nervous system (CNS) 74%, respiratory 72%, mucocutaneous 59%, and renal 31%, and hypotension was the presenting symptom in 43%. Coronary artery dilatation was seen in 1 (1.8%) child. All patients presented with more than three organs involvement. Raised procalcitonin was seen in 100%, raised BNP in 31.5%, low ejection fraction in 83.3%, and abnormal radiograph in 59%. All children were positive for anti-SARS-CoV-2 antibodies and negative for cultures. Methylprednisolone or intravenous immunoglobulin (IVIg) was used in 77%, mechanical ventilation in 18.5%, and inotropic support in 77%. Aspirin was used in 48% and low molecular weight heparin (LMWH) in 54%. The median stay in hospital was 7 d (IQR 2). There was 1 mortality (1.8%). On 7-d follow-up, 98% children had a normal echocardiography; on 6 mo and 1-y follow-up, all children had normal echocardiography.

CONCLUSION

MIS-C is an important complication of COVID-19 infection. Cardiac involvement resolves completely. Coronary artery involvement is not common.

Innate immune dysregulation in multisystem inflammatory syndrome in children (MIS-C)

MIS-C is a systemic inflammation disorder with poorly characterised immunopathological mechanisms. We compared changes in the systemic immune response in children with MIS-C (n = 12, 5-13 years) to healthy controls (n = 14, 5-15 years). Analysis was done in whole blood treated with LPS. Expression of CD11b and Toll-like receptor-4 (TLR4) in neutrophils and monocytes were analysed by flow cytometry. Serum cytokines (IL-1β, IL-2, IL-6, IL-8, IL-10, IL-Ira, TNF-α, TNF-β, IFN-Υ, VEGF, EPO and GM-CSF) and mRNA levels of inflammasome molecules (NLRP3, ASC and IL-1β) were evaluated. Subpopulations of lymphocytes (CD3+, CD19+, CD56+, CD4+, CD8+, TCR Vδ1+, TCR Vδ2+) were assessed at basal levels. Absolute counts of neutrophils and NLR were high in children with MIS-C while absolute counts of lymphocytes were low. Children with MIS-C had increased levels of IL-6, IL-10, TNF-β and VEGF serum cytokines at the basal level, and significantly increased TNF-β post-LPS, compared to controls. IL-1RA and EPO decreased at baseline and post-LPS in MIS-C patients compared to controls. The percentage of CD3+ cells, NK cells and Vδ1 was lower while B cells were higher in children with MIS-C than in controls. Dysregulated immune response in children with MIS-C was evident and may be amenable to immunomodulation.

A Single Center Observational Study on Clinical Manifestations and Associated Factors of Pediatric Long COVID

Children with SARS-CoV-2 are mostly mild symptomatic, but they may develop conditions, such as persisting symptoms, that may put them at greater risk of complications. Our aim was to evaluate the frequency and the presence of risk factors for persisting COVID-19 symptoms in children. We carried out a prospective observational study of the clinical manifestation of Long COVID at the Department of Maternal Infantile Science of a tertiary University hospital in Rome. We included 697 children (0-18 years), with previous SARS-CoV-2 infection. Children and parents were asked questions regarding persistent symptoms of COVID-19. Children with symptoms 30 days after initial diagnosis were 185/697 (26.4%). Moreover, 81/697 (11.6%) patients presented symptoms 90 days after the diagnosis. Thirty-day-persisting symptoms were mostly present in children with anosmia, atopy, asthenia, and cough in the acute phase compared with the asymptomatic children 30 days after infection. After 90 days, symptoms described were mainly neurological (47/697 children, 6.7%), and headache (19/697; 2.7%) was the most frequent manifestation. In conclusion, a relatively large proportion of the patients reported persisting symptoms that seem to be related to the symptom burden and to the atopy. Ninety days after the infection, most of the children had recovered, showing that long-term effects are not frequent. Limitations of the study include the single-center design and the lack of a control group.

Three-Dimensional Echocardiography and Global Longitudinal Strain in Follow-Up After Multisystem Inflammatory Syndrome in Children: Six-Month, Single-Center, Prospective Study

OBJECTIVE

To assess the potential long-term cardiac effects after multisystem inflammatory syndrome in children (MIS-C) with cardiovascular involvement in the acute phase.

STUDY DESIGN

Our prospective study involved children consecutively diagnosed with MIS-C between October 2020 and February 2022 and followed 6 weeks and 6 months after the disease. In patients with severe cardiac involvement during the acute phase, an additional check-up after 3 months was scheduled. In all patients at all check-ups, 3-dimensional echocardiography and global longitudinal strain (GLS) were used to assess ventricular function.

RESULTS

The study enrolled 172 children aged 1-17 years (median, 8 years). The means of ejection fraction (EF) and GLS for both ventricles were within normal limits after 6 weeks with no relationship with initial severity: left ventricular EF (LVEF) 60% (59%-63%), LV GLS -21.08% (-18.63% to -23.2%), right ventricular (RV) EF 64% (62%-67%), and RV GLS -22.8% (-20.5% to -24.5%). Further, statistically significant improvement of LV function was observed after 6 months-LVEF 63% (62%-65%) and LV GLS -22.55% (-21.05% to -24.25%; P < .05); however, RV function remained unchanged. The group with severe cardiac involvement showed LV function recovery pattern with no significant improvement between 6 weeks and 3 months after MIS-C, while still improving between 3 and 6 months after discharge.

CONCLUSIONS

LV and RV function is within normal limits 6 weeks after MIS-C regardless of severity of cardiovascular involvement; LV function improves further between 6 weeks and 6 months after the disease. The long-term prognosis is optimistic with full recovery of cardiac function.