Characteristics and Outcomes of US Children and Adolescents With Multisystem Inflammatory Syndrome in Children (MIS-C) Compared With Severe Acute COVID-19

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.

MIS-C Treatment: Is glucocorticoid monotherapy enough for mild cases?

BACKGROUND

The effectiveness of using only glucocorticoids (GCs) in mild multisystem inflammatory syndrome (MIS-C) cases was compared with combined treatment [GCs + Intravenous immune globulin (IVIG)].

METHODS

This retrospective cohort study was conducted between June 1, 2020, and June 1, 2022, in a tertiary care center in Istanbul, Turkey. Clinical and investigational data of the MIS-C patients were analyzed. The patients were divided into two groups: those who received only GCs and those who received the GCs + IVIG combination. The primary outcome focused on assessing the deterioration of the patient's clinical condition, the occurrence of shock, admission to the pediatric intensive care unit (PICU), and the need for additional immunosuppressive medication. Secondary outcomes included evaluating the course of cardiovascular and infection-related complications observed at the one-year follow-up.

RESULTS

Ninety-seven MIS-C patients with a median age of 41 (3- 214) months were enrolled. Fifty-six (57.7%) patients were male. All the patients had fever at admission with a temperature of 39 °C (37.5 °C-40.1 °C). Thirty-two patients (33%) had cardiac findings on echocardiography [left ventricular dysfunction (n= 13, 13.5%), coronary artery involvement (n= 11, 11.3%), and dilation of cardiac cavities and/or increased cardiac muscle thickness (n= 8, 8.2%)]. Thirteen patients (13.5%) required intensive care. All patients received GCs [only GCs (group I; n= 65, 67%)], and 32 patients (33%) with severe manifestations and/or cardiac involvement received GCs + IVIG (group II). No mortality was observed. None of the patients had any complaints at the one-year follow-up, and all echocardiography findings were normal.

CONCLUSION

This study provides preliminary evidence that GC monotherapy is a safe treatment alternative for mild MIS-C cases without cardiac involvement.

COVID-19 in Pediatric Populations

The COVID-19 pandemic reshaped the landscape of respiratory viral illnesses, causing common viruses to fade as SARS-CoV-2 took precedence. By 2023, more than 96% of the children in the United States were estimated to have been infected with SARS-CoV-2, with certain genetic predispositions and underlying health conditions posing risk factors for severe disease in children. Children, in general though, exhibit immunity advantages, protecting against aspects of the SARS-CoV-2 infection known to drive increased severity in older adults. Post-COVID-19 complications such as multisystem inflammatory syndrome in children and long COVID have emerged, underscoring the importance of vaccination. Here, we highlight the risks of severe pediatric COVID-19, age-specific immunoprotection, comparisons of SARS-CoV-2 with other respiratory viruses, and factors contributing to post-COVID-19 complications in children.

Effectiveness of early Anakinra on cardiac function in children with multisystem inflammatory syndrome of COVID-19: a systematic review

BACKGROUND

Multisystem Inflammatory Syndrome in Children (MIS-C) associated with SARS-CoV-2 can lead to severe cardiovascular complications. Anakinra, an interleukin-1 receptor antagonist, is proposed to benefit the hyperinflammatory state of MIS-C, potentially improving cardiac function. This systematic review evaluated the effectiveness of early Anakinra administration on cardiac outcomes in children with MIS-C.

METHODS

A comprehensive search across PubMed, Embase, and Web of Science until March 2024 identified studies using Anakinra to treat MIS-C with reported cardiac outcomes. Observational cohorts and clinical trials were included, with data extraction focusing on cardiac function metrics and inflammatory markers. Study quality was assessed using the Newcastle-Ottawa Scale.

RESULTS

Six studies met the inclusion criteria, ranging from retrospective cohorts to prospective clinical studies, predominantly from the USA. Anakinra dosages ranged from 2.3 to 10 mg/kg based on disease severity. Several studies showed significant improvements in left ventricular ejection fraction and reductions in inflammatory markers like C-reactive protein, suggesting Anakinra's role in enhancing cardiac function and mitigating inflammation. However, findings on vasoactive support needs were mixed, and some studies did not report significant changes in acute cardiac support requirements.

CONCLUSION

Early Anakinra administration shows potential for improving cardiac function and reducing inflammation in children with MIS-C, particularly those with severe manifestations. However, the existing evidence is limited by the observational nature of most studies and lacks randomized controlled trials (RCTs). Further high-quality RCTs are necessary to conclusively determine Anakinra's effectiveness and optimize its use in MIS-C management for better long-term cardiac outcomes and standardized treatment protocols.

Pre-existing Immunocompromising Conditions and Outcomes of Acute COVID-19 Patients Admitted for Pediatric Intensive Care

BACKGROUND

We aimed to determine if pre-existing immunocompromising conditions (ICCs) were associated with the presentation or outcome of patients with acute coronavirus disease 2019 (COVID-19) admitted for pediatric intensive care.

METHODS

Fifty-five hospitals in 30 US states reported cases through the Overcoming COVID-19 public health surveillance registry. Patients <21 years admitted 12 March 2020-30 December 2021 to the pediatric intensive care unit (PICU) or high-acuity unit for acute COVID-19 were included.

RESULTS

Of 1274 patients, 105 (8.2%) had an ICC, including 33 (31.4%) hematologic malignancies, 24 (22.9%) primary immunodeficiencies and disorders of hematopoietic cells, 19 (18.1%) nonmalignant organ failure with solid-organ transplantation, 16 (15.2%) solid tumors, and 13 (12.4%) autoimmune disorders. Patients with ICCs were older, had more underlying renal conditions, and had lower white blood cell and platelet counts than those without ICCs, but had similar clinical disease severity upon admission. In-hospital mortality from COVID-19 was higher (11.4% vs 4.6%, P = .005) and hospitalization was longer (P = .01) in patients with ICCs. New major morbidities upon discharge were not different between those with and without ICC (10.5% vs 13.9%, P = .40). In patients with ICCs, bacterial coinfection was more common in those with life-threatening COVID-19.

CONCLUSIONS

In this national case series of patients <21 years of age with acute COVID-19 admitted for intensive care, existence of a prior ICCs were associated with worse clinical outcomes. Reassuringly, most patients with ICCs hospitalized in the PICU for severe acute COVID-19 survived and were discharged home without new severe morbidities.

Efficacy, immunogenicity and safety of CoronaVac® in children and adolescents aged 6 months to 17 years: a multicenter, randomized, double-blind, placebo-controlled phase III clinical trial

Safe and effective vaccines against COVID-19 for children and adolescents are needed. This international multicenter, randomized, double-blind, placebo-controlled, phase III clinical trial assessed the efficacy, immunogenicity, and safety of CoronaVac® in children and adolescents (NCT04992260). The study was carried out in Chile, South Africa, Malaysia, and the Philippines. The enrollment ran from September 10, 2021 to March 25, 2022. For efficacy assessment, the median follow-up duration from 14 days after the second dose was 169 days. A total of 11,349 subjects were enrolled. Two 3-μg injections of CoronaVac® or placebo were given 28 days apart. The primary endpoint was the efficacy of the CoronaVac®. The secondary endpoints were the immunogenicity and safety. The vaccine efficacy was 21.02% (95% CI: 1.65, 36.67). The level of neutralizing antibody in the vaccine group was significantly higher than that in the placebo group (GMT: 390.80 vs. 62.20, P <0.0001). Most adverse reactions were mild or moderate. All the severe adverse events were determined to be unrelated to the investigational products. In conclusion, in the Omicron-dominate period, a two-dose schedule of 3 μg CoronaVac® was found to be safe and immunogenic, and showed potential against symptomatic COVID-19 in healthy children and adolescents.

High expression of oleoyl-ACP hydrolase underpins life-threatening respiratory viral diseases

Respiratory infections cause significant morbidity and mortality, yet it is unclear why some individuals succumb to severe disease. In patients hospitalized with avian A(H7N9) influenza, we investigated early drivers underpinning fatal disease. Transcriptomics strongly linked oleoyl-acyl-carrier-protein (ACP) hydrolase (OLAH), an enzyme mediating fatty acid production, with fatal A(H7N9) early after hospital admission, persisting until death. Recovered patients had low OLAH expression throughout hospitalization. High OLAH levels were also detected in patients hospitalized with life-threatening seasonal influenza, COVID-19, respiratory syncytial virus (RSV), and multisystem inflammatory syndrome in children (MIS-C) but not during mild disease. In olah-/- mice, lethal influenza infection led to survival and mild disease as well as reduced lung viral loads, tissue damage, infection-driven pulmonary cell infiltration, and inflammation. This was underpinned by differential lipid droplet dynamics as well as reduced viral replication and virus-induced inflammation in macrophages. Supplementation of oleic acid, the main product of OLAH, increased influenza replication in macrophages and their inflammatory potential. Our findings define how the expression of OLAH drives life-threatening viral disease.

Describing Elephants: An Update on the Immunopathology of Multisystem Inflammatory Syndrome in Children

First described in 2020, multi-system inflammatory syndrome in children (MIS-C) is an, initially life-threatening, disease characterised by severe inflammation and following exposure to SARS-CoV-2. The immunopathology of MIS-C involves a hyperinflammation characterised by a cytokine storm and activation of both the innate and adaptive immune system, eventually leading to multi-organ failure. Several etiological theories are described in literature. Firstly, it is suggested that the gut plays an important role in the translocation of microbial products to the systemic circulation. Additionally, the production of autoantibodies that develop after the initial infection with SARS-CoV-2 might lead to many of its broad clinical symptoms. Finally, the superantigen theory where non-specific binding of the SARS-CoV-2 spike glycoprotein to the T-cell receptor leads to a subsequent activation of T cells, generating a powerful immune response. Despite the sudden outbreak of MIS-C and alarming messages, as of 2024, cases have declined drastically and subsequently show a less severe clinical spectrum. However, subacute cases not meeting current diagnostic criteria might be overlooked even though they represent a valuable research population. In the future, research should focus on adjusting these criteria to better understand the broad pathophysiology of MIS-C, aiding early detection, therapy, and prediction.

Multisystemic inflammatory syndrome in children and the BNT162b2 vaccine: a nationwide cohort study

Multisystemic inflammatory syndrome in children (MIS-C) is a rare, severe, post-infectious hyperinflammatory condition that occurs after COVID-19 infection. In this study, we aimed to demonstrate the risk reduction of MIS-C and severe MIS-C after Pfizer-BioNTech BNT162b2 mRNA COVID-19 vaccination. This nationwide cohort study included 526,685 PCR-confirmed COVID-19 cases (age < 19 years), of whom 14,118 were fully vaccinated prior to COVID-19 infection. MIS-C cases were collected from all hospitals in Israel from April 2020 through November 2021. The MIS-C rates were calculated among two COVID-19 populations: positive PCR confirmed cases and estimated COVID-19 cases (PCR confirmed and presumed). Vaccination status was determined from Ministry of Health (MoH) records. The MIS-C risk difference (RD) and 95% confidence intervals (95%CI) between vaccinated and unvaccinated patients are presented. Overall, 233 MIS-C cases under the age of 19 years were diagnosed and hospitalized in Israel during the study period. Among the estimated COVID-19 cases, MIS-C RD realistically ranged between 2.1 [95%CI 0.7-3.4] and 1.0 [95%CI 0.4-1.7] per 10,000 COVID-19 cases. For severe MIS-C, RD realistically ranged between 1.6 [95%CI 1.3-1.9] and 0.8 [95%CI 0.7-1.0], per 10,000 COVID-19 cases. Sensitivity analysis was performed on a wide range of presumed COVID-19 rates, demonstrating significant RD for each of these rates.

CONCLUSION

This research demonstrates that vaccinating children and adolescents against COVID-19 has reduced the risk of MIS-C during the study period.

WHAT IS KNOWN

• Most of the published literature regarding vaccine effectiveness is based on case-control studies, which are limited due to small sample sizes and the inability to fully estimate the risk of MIS-C among vaccinated and unvaccinated children and adolescents. • The known underestimation of COVID-19 diagnosis among children and adolescents is challenging, as they often have few to no symptoms.

WHAT IS NEW

• Significant risk difference was found in favor of the vaccinated group, even after including extreme assumptions regarding the underdiagnosed COVID-19 rate. • During this nationwide study period, it was found that vaccinating children and adolescents reduced the risk of MIS-C and its complications.

Molecular mimicry in multisystem inflammatory syndrome in children

Multisystem inflammatory syndrome in children (MIS-C) is a severe, post-infectious sequela of SARS-CoV-2 infection1,2, yet the pathophysiological mechanism connecting the infection to the broad inflammatory syndrome remains unknown. Here we leveraged a large set of samples from patients with MIS-C to identify a distinct set of host proteins targeted by patient autoantibodies including a particular autoreactive epitope within SNX8, a protein involved in regulating an antiviral pathway associated with MIS-C pathogenesis. In parallel, we also probed antibody responses from patients with MIS-C to the complete SARS-CoV-2 proteome and found enriched reactivity against a distinct domain of the SARS-CoV-2 nucleocapsid protein. The immunogenic regions of the viral nucleocapsid and host SNX8 proteins bear remarkable sequence similarity. Consequently, we found that many children with anti-SNX8 autoantibodies also have cross-reactive T cells engaging both the SNX8 and the SARS-CoV-2 nucleocapsid protein epitopes. Together, these findings suggest that patients with MIS-C develop a characteristic immune response to the SARS-CoV-2 nucleocapsid protein that is associated with cross-reactivity to the self-protein SNX8, demonstrating a mechanistic link between the infection and the inflammatory syndrome, with implications for better understanding a range of post-infectious autoinflammatory diseases.

Spatial Accessibility and Uptake of Pediatric COVID-19 Vaccinations by Social Vulnerability

BACKGROUND AND OBJECTIVES

Geographic accessibility predicts pediatric preventive care utilization, including vaccine uptake. However, spatial inequities in the pediatric coronavirus disease 2019 (COVID-19) vaccination rollout remain underexplored. We assessed the spatial accessibility of vaccination sites and analyzed predictors of vaccine uptake.

METHODS

In this cross-sectional study of pediatric COVID-19 vaccinations from the US Vaccine Tracking System as of July 29, 2022, we described spatial accessibility by geocoding vaccination sites, measuring travel times from each Census tract population center to the nearest site, and weighting tracts by their population demographics to obtain nationally representative estimates. We used quasi-Poisson regressions to calculate incidence rate ratios, comparing vaccine uptake between counties with highest and lowest quartile Social Vulnerability Index scores: socioeconomic status (SES), household composition and disability (HCD), minority status and language (MSL), and housing type and transportation.

RESULTS

We analyzed 15 233 956 doses administered across 27 526 sites. Rural, uninsured, white, and Native American populations experienced longer travel times to the nearest site than urban, insured, Hispanic, Black, and Asian American populations. Overall Social Vulnerability Index, SES, and HCD were associated with decreased vaccine uptake among children aged 6 months to 4 years (overall: incidence rate ratio 0.70 [95% confidence interval 0.60-0.81]; SES: 0.66 [0.58-0.75]; HCD: 0.38 [0.33-0.44]) and 5 years to 11 years (overall: 0.85 [0.77-0.95]; SES: 0.71 [0.65-0.78]; HCD: 0.67 [0.61-0.74]), whereas social vulnerability by MSL was associated with increased uptake (6 months-4 years: 5.16 [3.59-7.42]; 5 years-11 years: 1.73 [1.44-2.08]).

CONCLUSIONS

Pediatric COVID-19 vaccine uptake and accessibility differed by race, rurality, and social vulnerability. National supply data, spatial accessibility measurement, and place-based vulnerability indices can be applied throughout public health resource allocation, surveillance, and research.

Extubated, Rehabilitation-Focused Extracorporeal Membrane Oxygenation for Pediatric Coronavirus Disease 2019: A Case Series

During the coronavirus 2019 (COVID-19) pandemic, children suffered severe lung injury resulting in acute respiratory distress syndrome requiring support with extracorporeal membrane oxygenation (ECMO). In this case series, we described our center's experience employing a rehabilitation-focused ECMO strategy including extubation during ECMO support in four pediatric patients with acute COVID-19 pneumonia hospitalized from September 2021 to January 2022. All four patients tolerated extubation within 30 days of ECMO initiation and achieved mobility while on ECMO support. Duration of ECMO support was 35-152 days and hospital lengths of stay were 52-167 days. Three of four patients survived. Two of three survivors had normal functional status at discharge except for ongoing respiratory support. The third survivor had significant motor deficits due to critical illness polyneuropathy and was supported with daytime oxygen and nocturnal noninvasive support. Overall, these patients demonstrated good outcomes and tolerance of a rehabilitation-focused ECMO strategy.

Cellular immune response to the anti-SARS-CoV-2 BNT162b2 mRNA vaccine in pediatric autoimmune inflammatory rheumatic disease patients and controls

This paper aims to compare the cellular immune response to the SARS-CoV-2 BNT162b2 vaccine of pediatric patients with autoimmune inflammatory rheumatic disease (pAIIRD) and healthy controls. A prospective longitudinal study was conducted between April 2021 and December 2022 at the Tel Aviv Medical Center. Children <18 years, with pediatric-onset AIIRD and healthy controls, who have received at least two doses of the BNT162b2 vaccine, were included. Humoral response was evaluated by serum levels of anti-SARS-CoV-2 receptor-binding domain antibodies. Cellular response was evaluated by flow cytometry, measuring IFNγ and TNFα production by CD4+ T cells following stimulation with SARS-CoV-2 Spike peptide mix. The study included 20 pAIIRD patients and 11 controls. The mean age of participants was 12.6 ± 2.94 years, with 58.1% females. The cellular response to the BNT162b2 vaccine was statistically similar in both groups. However, the humoral response was statistically lower in pAIIRD compared with the healthy control group. There was no statistically significant correlation between the humoral response and cellular response. During the study period, 43.75% of AIIRD children and 72.7% of controls had a breakthrough COVID-19 infection (P = 0.48). Bivariate models examining the effect of the cellular response and presence of an AIIRD on breakthrough infections found no effect. Compared with healthy controls, pAIIRD demonstrated similar cellular responses. Patients showed reduced humoral response compared with healthy adolescents, but similar breakthrough infection rates. These findings may support the importance of the cellular response in protecting against COVID-19 infections.

How international guidelines recommend treating children who have severe COVID-19 or risk disease progression

AIM

This study reviewed the current knowledge and guidelines on managing COVID-19 in children and proposed a practical approach to drug treatment.

METHODS

We analysed international guidelines from four prominent scientific bodies on treating COVID-19 in children. These were the UK National Institute for Health and Care Excellence, the American National Institutes of Health, the Infectious Diseases Society of America and the Australian National Clinical Evidence Taskforce COVID-19.

RESULTS

Most paediatric patients with COVID-19 only require symptomatic treatment. There was limited evidence on treatment recommendations for children with severe COVID-19 or at risk of disease progression. However, several drugs are available for children and we have summarised the guidelines, in order to provide a concise, practical format for clinicians. All the guidelines agree that nirmatrelvir plus ritonavir or remdesivir can be used as prophylaxis for severe COVID-19 in high-risk patients. Remdesivir can also be used for severe COVID-19 cases. Glucocorticosteroids are recommended, particularly in patients requiring oxygen therapy. Tocilizumab or baricitinib should be reserved for patients with progressive disease and/or signs of systemic inflammation.

CONCLUSION

The guidelines provide useful advice and a degree of consensus on specific drug treatment for children with severe COVID-19 or at risk of progression.

Should aortic stiffness parameters be used in MIS-C patient follow-up?

We evaluated the short- and long-term effects of multisystem inflammatory syndrome in children (MIS-C) on their cardiovascular system. The study population consisted of 38 MIS-C patients and 55 control patients. Standard echocardiographic measurements and aortic stiffness parameters were compared between the two groups at different time points. During the standard echocardiographic examination at the time of diagnosis, mitral valve insufficiency was detected in 42% of the cases, left ventricular systolic dysfunction in 36%, aortic valve insufficiency in 3%, tricuspid valve insufficiency in 13%, and coronary artery dilatation in 31%. The ejection fraction, pulse pressure of the experimental group were significantly lower than the control group (p < 0.01, p = 0.045, respectively). When aortic stiffness parameters were compared, it was seen that the parameters increased in the experimental group and the difference was significant for aortic distensibility. (p = 0.105, p = 0.029 respectively). When comparing the experimental group's results at diagnosis and at the sixth month, there was a decrease in aortic stiffness parameters at the sixth month compared to the time of diagnosis, but the difference wasn't significant (p = 0.514, p = 0.334). However, no statistically significant difference was detected when comparing the aortic distensibility results of the experimental group with the control group at the sixth month (p = 0.667). Our results showed that many pathological echocardiographic findings detected at diagnosis in MIS-C patients returned to normal within six months. Therefore, we believe that the cardiovascular follow-up period of MIS-C cases should be at least six months.

Infectious Diseases Society of America Guidelines on the Treatment and Management of Patients With COVID-19 (September 2022)

There are many pharmacologic therapies that are being used or considered for treatment of coronavirus disease 2019 (COVID-19), with rapidly changing efficacy and safety evidence from trials. The objective was to develop evidence-based, rapid, living guidelines intended to support patients, clinicians, and other healthcare professionals in their decisions about treatment and management of patients with COVID-19. In March 2020, the Infectious Diseases Society of America (IDSA) formed a multidisciplinary guideline panel of infectious disease clinicians, pharmacists, and methodologists with varied areas of expertise to regularly review the evidence and make recommendations about the treatment and management of persons with COVID-19. The process used a living guideline approach and followed a rapid recommendation development checklist. The panel prioritized questions and outcomes. A systematic review of the peer-reviewed and grey literature was conducted at regular intervals. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was used to assess the certainty of evidence and make recommendations. Based on the most recent search conducted on 31 May 2022, the IDSA guideline panel has made 32 recommendations for the treatment and management of the following groups/populations: pre- and postexposure prophylaxis, ambulatory with mild-to-moderate disease, and hospitalized with mild-to-moderate, severe but not critical, and critical disease. As these are living guidelines, the most recent recommendations can be found online at: https://idsociety.org/COVID19guidelines. At the inception of its work, the panel has expressed the overarching goal that patients be recruited into ongoing trials. Since then, many trials were conducted that provided much-needed evidence for COVID-19 therapies. There still remain many unanswered questions as the pandemic evolved, which we hope future trials can answer.

Immunogenicity, Safety, and Immune Persistence of One Dose of SARS-CoV-2 Recombinant Adenovirus Type-5 Vectored Vaccine in Children and Adolescents Aged 6-17 Years: An Immunobridging Trial

BACKGROUND

Though children infected by SARS-CoV-2 generally experience milder symptoms compared to adults, severe cases can occur. Additionally, children can transmit the virus to others. Therefore, the availability of safe and effective COVID-19 vaccines for children and adolescents is crucial.

METHOD

A single-center, randomized, double-blind clinical trial was conducted in Funing County, Yancheng City, Jiangsu Province, China. Healthy children and adolescents were divided into two subgroups (6-12 years old or 13-17 years old) and randomly assigned to one of three groups to receive one dose of Ad5-nCoV (3 × 1010 vp/dose). Another group, aged 18-59, received one dose of Ad5-nCoV (5 × 1010 vp/dose) as the control group. At 28, 90, 180, and 360 days post-vaccination, we measured the geometric mean titer (GMT)/concentration (GMC) of neutralizing and binding antibodies against the prototype SARS-CoV-2 strain, as well as serum antibody levels against the BA.4/5 variant. We also evaluated the incidence of adverse events within 28 days post-vaccination.

RESULTS

A total of 2413 individuals were screened from 3 June 2021 to 25 July 2021, of whom 2021 eligible participants were enrolled, including 1009 aged 6~17 years in the children and adolescent group and 1012 aged 18-59 years in the adults group. The GMT of anti-wild SARS-CoV-2 neutralizing antibodies was 18.6 (95% CI, 16.6-20.9) in children and adolescents and 13.2 (95% CI, 11.6-15.0) in adults on day 28. The incidence of solicited adverse reactions between the adult group (49.4% [124/251]) and the children and adolescent group (46.3% [156/337]) was not statistically significant. The neutralizing antibody levels decreased by a factor of 3.29 from day 28 to day 360 post-vaccination.

CONCLUSIONS

A single dose of Ad5-nCoV at 3 × 1010 virus particles/dose is safe in children and adolescents, and it elicited significant immune response, which was not only non-inferior but also superior to that in adults aged 18-59 years.

Inflammatory and Autoimmune Aspects of Multisystem Inflammatory Syndrome in Children (MIS-C): A Prospective Cohort Study

Multisystem Inflammatory Syndrome in Children (MIS-C) is a potentially life-threatening complication of COVID-19. The pathophysiological mechanisms leading to severe disease are poorly understood. This study leveraged clinical samples from a well-characterized cohort of children hospitalized with COVID-19 or MIS-C to compare immune-mediated biomarkers. Our objective was to identify selected immune molecules that could explain, in part, why certain SARS-CoV-2-infected children developed MIS-C. We hypothesized that type-2 helper T cell-mediated inflammation can elicit autoantibodies, which may account for some of the differences observed between the moderate-severe COVID-19 (COVID+) and MIS-C cohort. We enumerated blood leukocytes and measured levels of selected serum cytokines, chemokines, antibodies to COVID-19 antigens, and autoantibodies in children presenting to an academic medical center in Connecticut, United States. The neutrophil/lymphocyte and eosinophil/lymphocyte ratios were significantly higher in those in the MIS-C versus COVID+ cohort. IgM and IgA, but not IgG antibodies to SARS-CoV-2 receptor binding domain were significantly higher in the MIS-C cohort than the COVID+ cohort. The serum levels of certain type-2 cytokines (interleukin (IL)-4, IL-5, IL-6, IL-8, IL-10, IL-13, and IL-33) were significantly higher in children with MIS-C compared to the COVID+ and SARS-CoV-2-negative cohorts. IgG autoantibodies to brain antigens and pentraxin were higher in children with MIS-C compared to SARS-CoV-19-negative controls, and children with MIS-C had higher levels of IgG anti-contactin-associated protein-like 2 (caspr2) compared to the COVID+ and SARS-CoV-19-negative controls. We speculate that autoimmune responses in certain COVID-19 patients may induce pathophysiological changes that lead to MIS-C. The triggers of autoimmunity and factors accounting for type-2 inflammation require further investigation.

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.

Severe Pediatric Neurological Manifestations With SARS-CoV-2 or MIS-C Hospitalization and New Morbidity

Importance

Neurological manifestations during acute SARS-CoV-2-related multisystem inflammatory syndrome in children (MIS-C) are common in hospitalized patients younger than 18 years and may increase risk of new neurocognitive or functional morbidity.

Objective

To assess the association of severe neurological manifestations during a SARS-CoV-2-related hospital admission with new neurocognitive or functional morbidities at discharge.

Design, Setting, and Participants

This prospective cohort study from 46 centers in 10 countries included patients younger than 18 years who were hospitalized for acute SARS-CoV-2 or MIS-C between January 2, 2020, and July 31, 2021.

Exposure

Severe neurological manifestations, which included acute encephalopathy, seizures or status epilepticus, meningitis or encephalitis, sympathetic storming or dysautonomia, cardiac arrest, coma, delirium, and stroke.

Main Outcomes and Measures

The primary outcome was new neurocognitive (based on the Pediatric Cerebral Performance Category scale) and/or functional (based on the Functional Status Scale) morbidity at hospital discharge. Multivariable logistic regression analyses were performed to examine the association of severe neurological manifestations with new morbidity in each SARS-CoV-2-related condition.

Results

Overall, 3568 patients younger than 18 years (median age, 8 years [IQR, 1-14 years]; 54.3% male) were included in this study. Most (2980 [83.5%]) had acute SARS-CoV-2; the remainder (588 [16.5%]) had MIS-C. Among the patients with acute SARS-CoV-2, 536 (18.0%) had a severe neurological manifestation during hospitalization, as did 146 patients with MIS-C (24.8%). Among survivors with acute SARS-CoV-2, those with severe neurological manifestations were more likely to have new neurocognitive or functional morbidity at hospital discharge compared with those without severe neurological manifestations (27.7% [n = 142] vs 14.6% [n = 356]; P < .001). For survivors with MIS-C, 28.0% (n = 39) with severe neurological manifestations had new neurocognitive and/or functional morbidity at hospital discharge compared with 15.5% (n = 68) of those without severe neurological manifestations (P = .002). When adjusting for risk factors in those with severe neurological manifestations, both patients with acute SARS-CoV-2 (odds ratio, 1.85 [95% CI, 1.27-2.70]; P = .001) and those with MIS-C (odds ratio, 2.18 [95% CI, 1.22-3.89]; P = .009) had higher odds of having new neurocognitive and/or functional morbidity at hospital discharge.

Conclusions and Relevance

The results of this study suggest that children and adolescents with acute SARS-CoV-2 or MIS-C and severe neurological manifestations may be at high risk for long-term impairment and may benefit from screening and early intervention to assist recovery.

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.

Novel insights into the immune response to bacterial T cell superantigens

Bacterial T cell superantigens (SAgs) are a family of microbial exotoxins that function to activate large numbers of T cells simultaneously. SAgs activate T cells by direct binding and crosslinking of the lateral regions of MHC class II molecules on antigen-presenting cells with T cell receptors (TCRs) on T cells; these interactions alter the normal TCR-peptide-MHC class II architecture to activate T cells in a manner that is independent of the antigen specificity of the TCR. SAgs have well-recognized, central roles in human diseases such as toxic shock syndrome and scarlet fever through their quantitative effects on the T cell response; in addition, numerous other consequences of SAg-driven T cell activation are now being recognized, including direct roles in the pathogenesis of endocarditis, bloodstream infections, skin disease and pharyngitis. In this Review, we summarize the expanding family of bacterial SAgs and how these toxins can engage highly diverse adaptive immune receptors. We highlight recent findings regarding how SAg-driven manipulation of the adaptive immune response may operate in multiple human diseases, as well as contributing to the biology and life cycle of SAg-producing bacterial pathogens.

Evaluation of Long-Term Posterior Segment Parameters in Children Who Had Recovered From Multisystem Inflammatory Syndrome

BACKGROUND AND OBJECTIVE

To evaluate long-term posterior segment findings in children recovering from multisystemic inflammatory syndrome (MIS-C) associated with severe acute respiratory syndrome coronavirus 2.

PATIENTS AND METHODS

Our study included 22 patients who were admitted to an intensive care unit with a diagnosis of MIS-C between November 2021 and March 2022, and 25 healthy controls. The study included pediatric patients who had an eye examination an average of 12.35 ± 2.18 months after recovery from MIS-C. Detailed eye examinations and measurements of all participants were obtained retrospectively from patient files. Posterior segment parameters were measured using swept-source optical coherence tomography (OCT) and OCT-angiography (OCT-A); these parameters included peripapillary retinal nerve fiber layer (pRNFL) thickness, central macular thickness (CMT), subfoveal choroidal thickness (SCT), macular vascular densities (VD), and foveal avascular zone (FAZ) area.

RESULTS

Mean age was 9.7 ± 3.6 years in the MIS-C group and 10.6 ± 2.8 years in the healthy control group (P = 0.316). There were no statistically significant differences between the MIS-C group and the healthy control group in terms of pRNFL thickness, CMT, and SCT. However, in the MIS-C group, the macular superficial vascular plexus and deep vascular plexus showed significantly lower VD in the superior, inferior, nasal, and temporal quadrants compared to the healthy controls (P < 0.05 for all). A comparison of the superficial and deep FAZ area parameters of both groups showed no statistically significant difference (P > 0.05).

CONCLUSIONS

We showed that patients who had recovered from MIS-C had retinal vascular damage at the long-term follow-up. Following up with these patients after recovery with OCT and OCT-A, which are noninvasive methods commonly used in the detailed evaluation of the posterior segment of the eye, could be beneficial for understanding the long-term effects of MIS-C on retinal microvasculature. [Ophthalmic Surg Lasers Imaging Retina 2024;55:XX-XX.].

SCARLET (Supplemental Citicoline Administration to Reduce Lung injury Efficacy Trial): study protocol for a single-site, double-blinded, placebo-controlled, and randomized Phase 1/2 trial of i.v. citicoline (CDP-choline) in hospitalized SARS CoV-2-infected patients with hypoxemic acute respiratory failure

BACKGROUND

The SARS CoV-2 pandemic has resulted in more than 1.1 million deaths in the USA alone. Therapeutic options for critically ill patients with COVID-19 are limited. Prior studies showed that post-infection treatment of influenza A virus-infected mice with the liponucleotide CDP-choline, which is an essential precursor for de novo phosphatidylcholine synthesis, improved gas exchange and reduced pulmonary inflammation without altering viral replication. In unpublished studies, we found that treatment of SARS CoV-2-infected K18-hACE2-transgenic mice with CDP-choline prevented development of hypoxemia. We hypothesize that administration of citicoline (the pharmaceutical form of CDP-choline) will be safe in hospitalized SARS CoV-2-infected patients with hypoxemic acute respiratory failure (HARF) and that we will obtain preliminary evidence of clinical benefit to support a larger Phase 3 trial using one or more citicoline doses.

METHODS

We will conduct a single-site, double-blinded, placebo-controlled, and randomized Phase 1/2 dose-ranging and safety study of Somazina® citicoline solution for injection in consented adults of any sex, gender, age, or ethnicity hospitalized for SARS CoV-2-associated HARF. The trial is named "SCARLET" (Supplemental Citicoline Administration to Reduce Lung injury Efficacy Trial). We hypothesize that SCARLET will show that i.v. citicoline is safe at one or more of three doses (0.5, 2.5, or 5 mg/kg, every 12 h for 5 days) in hospitalized SARS CoV-2-infected patients with HARF (20 per dose) and provide preliminary evidence that i.v. citicoline improves pulmonary outcomes in this population. The primary efficacy outcome will be the SpO2:FiO2 ratio on study day 3. Exploratory outcomes include Sequential Organ Failure Assessment (SOFA) scores, dead space ventilation index, and lung compliance. Citicoline effects on a panel of COVID-relevant lung and blood biomarkers will also be determined.

DISCUSSION

Citicoline has many characteristics that would be advantageous to any candidate COVID-19 therapeutic, including safety, low-cost, favorable chemical characteristics, and potentially pathogen-agnostic efficacy. Successful demonstration that citicoline is beneficial in severely ill patients with SARS CoV-2-induced HARF could transform management of severely ill COVID patients.

TRIAL REGISTRATION

The trial was registered at www.

CLINICALTRIALS

gov on 5/31/2023 (NCT05881135).

TRIAL STATUS

Currently enrolling.

Retrospective Analysis of Clinical Characteristics and Disease Outcomes in Children and Adolescents Hospitalized Due to COVID-19 Infection in Tunisia

Due to low susceptibility of coronavirus disease of 2019 (COVID-19) in children, limited studies are available regarding COVID-19 in the pediatric population in Tunisia. The current study evaluated the incidence, clinical characteristics, and outcomes of severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) infection among children hospitalized at Béchir Hamza Children's Hospital. A retrospective cohort analysis was conducted using the hospital database between March 2020 and February 2022 with children aged ≤15 years with SARS-CoV-2 infection (confirmed by RT-PCR). A total of 327 COVID-19 hospitalized patients with a mean age of 3.3 years were included; the majority were male. Neurological disease (20%) was the most common comorbidity, while fever (95.3%) followed by cough (43.7%) and dyspnea (39.6%) were the most frequent symptoms reported. Severe disease with oxygen requirement occurred in 30% of the patients; 13% were admitted in the Intensive Care Unit. The overall incidence rate of COVID-19 hospitalization (in Tunis governorates) was 77.02 per 100,000 while the inpatient case fatality rate was 5% in the study population. The most prevalent circulating variant during our study period was Delta (48.8%), followed by Omicron (26%). More than 45% of the study population were <6 months and one-fourth (n = 25, 26.5%) had at least one comorbidity. Thus, the study findings highlight the high disease burden of COVID-19 in infants.

Relationship between gastrointestinal symptoms and COVID-19 infection in the pediatric population: a scoping review

OBJECTIVE

To map the evidence in the literature about the relationship between gastrointestinal symptoms and COVID-19 in the pediatric population.

METHOD

This is a scoping review following the recommendations of the Joanna Briggs Institute and PRISMA Extension for Scoping Reviews (PRISMA-ScR): Checklist and Explanation. The search was carried out on the following bases: Embase, Google Scholar, PubMed, Scopus, LILACS, CINAHL, Scielo, Web of Science and Virtual Health Library Portal, between July and August 2023. Original studies available in full, in any language, were included.

RESULTS

Ten studies were chosen that pointed to three premises: (1) the ACE2 receptor is found in the epithelial cells of the gastrointestinal tract; (2) gastrointestinal symptoms are mediated by stress and infection is justified by the gut-brain axis; (3) it develops the process of Multisystem Inflammatory Syndrome in children, affecting the gastrointestinal tract.

CONCLUSION

The synthesis of evidence provided three assumptions which guide the origin of gastrointestinal symptoms. The identification of gastrointestinal symptoms in children affected by COVID-19 can assist in the clinical approach and management of care and treatments.

Specialty follow -up care after hospital discharge of patients with multisystem inflammatory syndrome in children associated with COVID-19 from a rural tertiary-care hospital

BACKGROUND

The clinical features of Multisystem Inflammatory Syndrome in Children (MIS-C) have been well documented, but there is limited data regarding the short term and longitudinal outcomes of children living in rural areas. We report the demographic and clinical features, as well as the multi-specialty follow-up of patients with MIS-C served by a large tertiary care rural health system.

METHODS

Patients that met the Centers for Disease Control (CDC) case definition of MIS-C admitted between March 1, 2020, and March 31, 2021, were included in this case series. Manual chart review was used to report demographic characteristics, clinical, laboratory and radiologic features during acute hospitalization and multispecialty follow-up, and adherence to follow-up 6-10 weeks after hospital discharge.

RESULTS

Twenty-one patients with MIS-C were admitted at our center during the review period. Ninety percent of the cohort required intensive care during hospitalization. Of 19 patients with measured ejection fractions, 52 % had some degree of left ventricular dysfunction on admission; nine patients had electrocardiogram changes on admission. The majority of patients had elevated inflammatory markers during hospitalization. Most patients had resolution of symptoms, improvement in inflammatory markers, and normal cardiac function at the time of discharge. Follow-up with pediatric cardiology, hematology-oncology and infectious disease was indicated for most patients at discharge. Of these, 100 % of patients kept initial follow-up appointments with pediatric cardiology and infectious disease, while 94 % kept initial follow-up appointments with pediatric hematology-oncology.

CONCLUSION

Though most patients were critically ill during hospitalization, the majority had resolution of cardiac abnormalities and inflammatory markers at discharge and timely follow-up with multiple subspecialists after admission with MIS-C.

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.

Lessons from the Pandemic: Role of Percutaneous ECMO and Balloon Atrial Septostomy in Multi-System Inflammatory Syndrome in Children

Multi-system inflammatory syndrome in children (MIS-C) in the setting of COVID-19 can be associated with severe cardiopulmonary dysfunction. This clinical deterioration may sometimes necessitate veno-arterial extracorporeal membrane oxygenation (VA-ECMO) support. We describe an algorithmic approach including the role of balloon atrial septostomy in this cohort. This is the first reported series of percutaneous VA-ECMO in pediatric patients with MIS-C for better outcomes. The lessons from this approach can be replicated in other pediatric clinical conditions and adds to the armament of multiple pediatric specialties.

Severe pediatric COVID-19: a review from the clinical and immunopathophysiological perspectives

BACKGROUND

Coronavirus disease 2019 (COVID-19) tends to have mild presentations in children. However, severe and critical cases do arise in the pediatric population with debilitating systemic impacts and can be fatal at times, meriting further attention from clinicians. Meanwhile, the intricate interactions between the pathogen virulence factors and host defense mechanisms are believed to play indispensable roles in severe COVID-19 pathophysiology but remain incompletely understood.

DATA SOURCES

A comprehensive literature review was conducted for pertinent publications by reviewers independently using the PubMed, Embase, and Wanfang databases. Searched keywords included "COVID-19 in children", "severe pediatric COVID-19", and "critical illness in children with COVID-19".

RESULTS

Risks of developing severe COVID-19 in children escalate with increasing numbers of co-morbidities and an unvaccinated status. Acute respiratory distress stress and necrotizing pneumonia are prominent pulmonary manifestations, while various forms of cardiovascular and neurological involvement may also be seen. Multiple immunological processes are implicated in the host response to COVID-19 including the type I interferon and inflammasome pathways, whose dysregulation in severe and critical diseases translates into adverse clinical manifestations. Multisystem inflammatory syndrome in children (MIS-C), a potentially life-threatening immune-mediated condition chronologically associated with COVID-19 exposure, denotes another scientific and clinical conundrum that exemplifies the complexity of pediatric immunity. Despite the considerable dissimilarities between the pediatric and adult immune systems, clinical trials dedicated to children are lacking and current management recommendations are largely adapted from adult guidelines.

CONCLUSIONS

Severe pediatric COVID-19 can affect multiple organ systems. The dysregulated immune pathways in severe COVID-19 shape the disease course, epitomize the vast functional diversity of the pediatric immune system and highlight the immunophenotypical differences between children and adults. Consequently, further research may be warranted to adequately address them in pediatric-specific clinical practice guidelines.

Multisystem inflammatory syndrome in children associated with COVID-19: from pathophysiology to clinical management and outcomes

Multisystem inflammatory syndrome in children (MIS-C), also known as pediatric inflammatory multisystem syndrome (PIMS), is a new postinfectious illness associated with COVID-19, affecting children after SARS-CoV-2 exposure. The hallmarks of this disorder are hyperinflammation and multisystem involvement, with gastrointestinal, cardiac, mucocutaneous, and hematologic disturbances seen most commonly. Cardiovascular involvement includes cardiogenic shock, ventricular dysfunction, coronary artery abnormalities, and myocarditis. Now entering the fourth year of the pandemic, clinicians have gained some familiarity with the clinical presentation, initial diagnosis, cardiac evaluation, and treatment of MIS-C. This has led to an updated definition from the Centers for Disease Control and Prevention in the USA driven by increased experience and clinical expertise. Furthermore, the available evidence established expert consensus treatment recommendations supporting a combination of immunoglobulin and steroids. However, the pathophysiology of the disorder and answers to what causes this remain under investigation. Fortunately, long-term outcomes continue to look promising, although continued follow-up is still needed. Recently, COVID-19 mRNA vaccination is reported to be associated with reduced risk of MIS-C, while further studies are warranted to understand the impact of COVID-19 vaccines on MIS-C. We review the findings and current literature on MIS-C, including pathophysiology, clinical features, evaluation, management, and medium- to long-term follow-up outcomes.

Clinical Predictors of Subacute Myocardial Dysfunction in Multisystem Inflammatory Syndrome in Children (MIS-C) Associated with COVID-19

Multisystem Inflammatory Syndrome in Children (MIS-C) often involves a post-viral myocarditis and associated left ventricular dysfunction. We aimed to assess myocardial function by strain echocardiography after hospital discharge and to identify risk factors for subacute myocardial dysfunction. We conducted a retrospective single-center study of MIS-C patients admitted between 03/2020 and 03/2021. Global longitudinal strain (GLS), 4-chamber longitudinal strain (4C-LS), mid-ventricular circumferential strain (CS), and left atrial strain (LAS) were measured on echocardiograms performed 3-10 weeks after discharge and compared with controls. Among 60 MIS-C patients, hypotension (65%), ICU admission (57%), and vasopressor support (45%) were common, with no mortality. LVEF was abnormal (< 55%) in 29% during hospitalization but only 4% at follow-up. Follow-up strain abnormalities were prevalent (GLS abnormal in 13%, 4C-LS in 18%, CS in 16%, LAS in 5%). Hypotension, ICU admission, ICU and hospital length of stay, and any LVEF < 55% during hospitalization were factors associated with lower strain at follow-up. Higher peak C-reactive protein (CRP) was associated with hypotension, ICU admission, total ICU days, and with lower follow-up GLS (r = - 0.55; p = 0.01) and CS (r = 0.41; p = 0.02). Peak CRP < 18 mg/dL had negative predictive values of 100% and 88% for normal follow-up GLS and CS, respectively. A subset of MIS-C patients demonstrate subclinical systolic and diastolic function abnormalities at subacute follow-up. Peak CRP during hospitalization may be a useful marker for outpatient cardiac risk stratification. MIS-C patients with hypotension, ICU admission, any LVEF < 55% during hospitalization, or a peak CRP > 18 mg/dL may warrant closer monitoring than those without these risk factors.

Unveiling parental perspectives: COVID-19 vaccination for children in India

Background

Irrespective of the availability of a safe and effective COVID-19 vaccine and its success rate in adults, administering vaccines to children remains a challenge for healthcare workers. Children's vaccine hesitancy among parents remains substantial and is exacerbated due to misleading information. In the present study, we aimed to investigate the hesitancy of parents and their concern about the vaccination and clinical characteristics of COVID-19 in their children.

Methods

A cross-sectional web-based and offline survey comprised of questions about the demographic of children, the status of COVID-19 infection, its severity, vaccination status, sources of information, willingness, concerns and attitude of parents to vaccinate their children against the COVID-19 virus, was conducted. Overall, 846 responses from parents fulfilling the inclusion criteria were analysed by GraphPad Prism 5.

Results

Out of the 846 responses, 51.2% (n = 433) of children were vaccinated against COVID-19. Out of vaccinated children (51.2%), 60.3% (n = 261) had experienced adverse events. Around 21% (n = 98) of children had a history of exposure to the SARS-CoV-2 virus. Among the infected children, 14.3% were asymptomatic and 85.7% had symptoms. Approximately 8% of children had comorbidities, with chronic lung diseases and asthma being the most common. Among the 846 participating parents, 59.5% were mothers and the remaining 40.5% were fathers. A total of 2.7% and 22.2% of parents were found hesitant to administer the COVID-19 vaccine to their children aged 15-18 years and below 15 years, respectively. Among hesitant parents, mothers were found slightly more hesitant as compared to fathers. Also, 35.5% of parents were found hesitant about their own COVID-19 vaccination. Furthermore, the concern for COVID-19 vaccine unwillingness among parents is that a child has already achieved natural immunity after COVID-19 infections (76.8%) followed by vaccine safety and its side effects. The motivating factors to convince parents for their children's COVID-19 vaccination were if their doctors recommend it, followed by detailed information on vaccine side effects and efficacy in children. The most trusted source of information for the parents was found to be the healthcare workers.

Conclusion

These results suggest that data and reviews regarding the safety and efficacy of the COVID-19 vaccine readily available in the public domain could serve as a highly effective strategy for promoting and implementing widespread vaccination among children. By providing easily accessible and comprehensive information, public health authorities can address parental concerns, dispel misconceptions and foster a greater sense of trust in the vaccination process.

Neurological diagnoses in hospitalized COVID-19 patients associated with adverse outcomes: A multinational cohort study

Few studies examining the patient outcomes of concurrent neurological manifestations during acute COVID-19 leveraged multinational cohorts of adults and children or distinguished between central and peripheral nervous system (CNS vs. PNS) involvement. Using a federated multinational network in which local clinicians and informatics experts curated the electronic health records data, we evaluated the risk of prolonged hospitalization and mortality in hospitalized COVID-19 patients from 21 healthcare systems across 7 countries. For adults, we used a federated learning approach whereby we ran Cox proportional hazard models locally at each healthcare system and performed a meta-analysis on the aggregated results to estimate the overall risk of adverse outcomes across our geographically diverse populations. For children, we reported descriptive statistics separately due to their low frequency of neurological involvement and poor outcomes. Among the 106,229 hospitalized COVID-19 patients (104,031 patients ≥18 years; 2,198 patients <18 years, January 2020-October 2021), 15,101 (14%) had at least one CNS diagnosis, while 2,788 (3%) had at least one PNS diagnosis. After controlling for demographics and pre-existing conditions, adults with CNS involvement had longer hospital stay (11 versus 6 days) and greater risk of (Hazard Ratio = 1.78) and faster time to death (12 versus 24 days) than patients with no neurological condition (NNC) during acute COVID-19 hospitalization. Adults with PNS involvement also had longer hospital stay but lower risk of mortality than the NNC group. Although children had a low frequency of neurological involvement during COVID-19 hospitalization, a substantially higher proportion of children with CNS involvement died compared to those with NNC (6% vs 1%). Overall, patients with concurrent CNS manifestation during acute COVID-19 hospitalization faced greater risks for adverse clinical outcomes than patients without any neurological diagnosis. Our global informatics framework using a federated approach (versus a centralized data collection approach) has utility for clinical discovery beyond COVID-19.

Myeloid-derived suppressor cells and T cell populations in children with Multisystem Inflammatory Syndrome

BACKGROUND

Multisystem inflammatory syndrome in children (MIS-C) represents a hyperinflammatory state that can result in multi-organ dysfunction and death. Myeloid-derived suppressor cells (MDSC) are an immunosuppressive cell population that expands under inflammatory conditions and suppresses T cell function. We hypothesized that MDSC would be increased in children with MIS-C and that MDSC expansion would be associated with T cell lymphopenia.

METHODS

We conducted a prospective, observational study. Initial blood samples were collected within 48 h of admission. Age-matched healthy controls underwent sampling once. MDSC and T cell populations were identified by flow cytometric methods.

RESULTS

We enrolled 22 children with MIS-C (12 ICU, 10 ward) and 21 healthy controls (HC). Children with MIS-C demonstrated significantly higher MDSC compared to HC, and MDSC expansion persisted for >3 weeks in the ICU group. Children with MIS-C admitted to the ICU demonstrated significantly lower absolute numbers of T cells and natural killer cells. There were no significant associations between MDSC and cardiac dysfunction, duration of hospitalization, or vasoactive inotrope score.

CONCLUSIONS

Our study suggests that children critically ill with MIS-C have expansion of MDSC and associated decreased T cell and NK cell populations. Our results did not demonstrate associations between MDSC and clinical outcomes.

IMPACT

Multisystem inflammatory syndrome in children (MIS-C) is a dysregulated immune response occurring several weeks after SARS-CoV-2 infection that can result in multi-organ dysfunction and death. Children severely ill with MIS-C demonstrated increased myeloid-derived suppressor cells and decreased absolute numbers of CD4+ and CD8 + T cells and NK cells compared to healthy controls. There was no significant association between MDSC numbers and clinical outcomes; including cardiac dysfunction, length of stay, or requirement of vasoactive support, in children with MIS-C.

Cytokine storm in Chikungunya: Can we call it multisystem inflammatory syndrome associated with Chikungunya?

Paraguay is currently facing a new outbreak of Chikungunya virus. This report summarizes two severe cases of Chikungunya (CHIKV) infection, confirmed by real-time reverse transcription polymerase chain reaction. We present the cases of patients with acute CHIKV infection and multisystem involvement, with fever, rash, abdominal pain, vomiting, myocarditis, and coronary artery anomalies, very similar to the cases described in MIS-C related to SARS-CoV-2 during the COVID-19 Pandemic. Both patients received IVIG and methylprednisolone, with good clinical response. In this setting of cytokine storm in Chikungunya, can we call it "Multisystem inflammatory syndrome associated with Chikungunya"?.

Left Atrial Strain in Multisystem Inflammatory Syndrome in Children and Associations with Systemic Inflammation and Cardiac Injury

Multisystem inflammatory syndrome in children (MIS-C) commonly involves cardiac injury with both systolic and diastolic dysfunction. Left atrial strain (LAS) detects subclinical diastolic dysfunction in adults but is infrequently used in children. We evaluated LAS in MIS-C and the associations with systemic inflammation and cardiac injury. In this retrospective cohort study, LAS parameters [reservoir (LAS-r), conduit (LAS-cd), and contractile (LAS-ct)] obtained from admission echocardiograms of MIS-C patients were compared to healthy controls and between MIS-C patients with and without cardiac injury (BNP > 500 pg/ml or troponin-I > 0.04 ng/ml). Correlation and logistic regression analyses were performed to assess LAS associations with admission inflammatory and cardiac biomarkers. Reliability testing was performed. We identified 118 patients with MIS-C and 20 healthy controls. Median LAS parameters were reduced in MIS-C patients compared to controls (LAS-r: 31.8 vs. 43.1%, p < 0.001; LAS-cd: - 28.8 vs. - 34.5%, p = 0.006; LAS-ct: - 5.2 vs. - 9.3%, p < 0.001) and reduced in MIS-C patients with cardiac injury (n = 59) compared to no injury (n = 59) (LAS-r: 29.6 vs. 35.8%, p = 0.001; LAS-cd: - 26.5 vs. - 30.4%, p = 0.036; LAS-ct: - 4.6 vs. - 9.3%, p = 0.008). A discrete LAS-ct peak was absent in 65 (55%) MIS-C patients but present in all controls (p < 0.001). Procalcitonin correlated strongly with averaged E/e' (r = 0.55, p = 0.001). Moderate correlations were found for ESR and LAS-ct (r = - 0.41, p = 0.007) as well as BNP and LAS-r (r = - 0.39, p < 0.001) and LAS-ct (r = 0.31, p = 0.023). Troponin-I had only weak correlations. Intra-rater reliability was good for all LAS parameters, and inter-rater reliability was good to excellent for LAS-r, and fair for LAS-cd and LAS-ct. LAS analysis, particularly the absence of a LAS-ct peak, was reproducible and may be superior to conventional echocardiographic parameters for detecting diastolic dysfunction in MIS-C. No strain parameters on admission were independently associated with cardiac injury.

What the SARS-CoV-2 Pandemic Has Taught Us About Immunosuppression, Vaccinations, and Immune Dysregulation: The Rheumatology Experience

PURPOSE OF REVIEW

This review reflects on the impact of the COVID-19 pandemic on the field of rheumatology, emphasizing resulting insights related to the risks of viral infections in immunosuppressed patients, vaccine immunogenicity in immunocompromised patients, and immune dysregulation in the setting of viral infection.

RECENT FINDINGS

During the pandemic, global patient registries provided real-time insights into the risk factors associated with severe COVID-19 outcomes in rheumatology patients. Updated evidence-based recommendations from the American College of Rheumatology (ACR) guided rheumatology practice during a time of considerable uncertainty. Studies on COVID-19 vaccines in immunocompromised populations enhanced our understanding of specific immunosuppressive therapies on vaccine efficacy. The immune dysregulation seen in severe COVID-19 underscored a role for immunomodulation in this and other severe infections. Furthermore, novel post-infectious conditions, namely multisystem inflammatory syndrome in children (MIS-C) and Long COVID, reshaped our understanding of post-viral syndromes and revealed novel pathological mechanisms. Lessons from the COVID-19 pandemic demonstrate the power of collaborative research. The scientific revelations from this dreadful time will, nonetheless, benefit the practice of rheumatology for years to come.

A bibliometric analysis of Kawasaki disease from 1974 to 2022

Objective

To analyse the research history, development trends and current status of relevant literature in the field of Kawasaki disease, and to provide the basis for future directions in Kawasaki disease (KD) research.

Methods

Literature on Kawasaki disease published between January 1974 and December 2022 was searched for in the Web of Science database, and CiteSpace was used to perform visual analyses.

Results

The search yielded a total of 6950 articles. The number of publications related to Kawasaki disease showed an increasing trend. A collaborative network analysis revealed that the United States, Japan and mainland China were the most influential countries in this field. The University of California system contributed the most publications and the journal with the most publications was Circulation. JW Newburger was an authoritative author in this field. "Coronary artery lesion", "Intravenous immunoglobulin" (IVIG) and "Risk factor" were three prominent keywords. Keyword bursts changed from "TNF" and "IVIG", which focused on aetiology and treatment, to "Long term management", which emphasized the recovery period, and to "Kawasaki-like disease" and "Multisystem inflammatory syndrome" during the novel coronavirus pandemic. Trends of highly cited references indicated that landmark articles in different periods focused on Kawasaki disease guidelines, gene polymorphisms and multisystem inflammatory syndrome caused by the novel coronavirus.

Conclusion

The aetiology of Kawasaki disease remains unclear, but viral infection is likely to play an important role. The combination of evolving sequencing technologies, large-scale epidemiological investigations and prospective cohort studies is likely to be important in exploring Kawasaki disease and improving its prognosis in future.

Multisystem inflammatory syndrome in children (MIS-C) post-COVID-19 in Iran: clinical profile, cardiac features, and outcomes

BACKGROUND

In April 2020, an association between multisystem inflammatory syndromes (MIS-C) was observed in children with severe acute respiratory syndrome coronavirus infection (SARS-CoV-2). Most patients had heart involvement alone, and most patients had pericardial effusion. This study aimed to express and emphasize cardiac involvement in pediatric patients with respiratory symptoms who were diagnosed with COVID-19.

METHODS

This study was conducted in July 2021 in Kerman province, Southeastern Iran, during a notable surge in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. The study included 904 pediatric patients diagnosed with COVID-19. Data collection involved a comprehensive assessment of clinical symptoms and manifestations. Patients with fever lasting more than five days were admitted to the hospital. Echocardiography was utilized for cardiac involvement diagnosis, with 47 patients undergoing this diagnostic procedure.

RESULTS

Of the 904 patients, most of them had high fevers (74%). Fifty-five patients had a fever for more than five days and were hospitalized. Of the 47 patients who underwent echocardiography, 45 (81%) had heart involvement. In 75% of patients, pericardial effusion was the only cardiac involvement. Patients with pericardial effusion were treated with dexamethasone up to 3 mg every 8 h for 72 h.

CONCLUSIONS

MIS-C has a wide range of clinical symptoms. In cases where the fever is prolonged and there are gastrointestinal symptoms, physicians have clinical suspicion to diagnose this syndrome. Most cases of pericardial effusion are alone and improve with treatment with glucocorticosteroids.

Factors associated to mortality in children with critical COVID-19 and multisystem inflammatory syndrome in a resource-poor setting

SARS-CoV-2 infection in children is usually asymptomatic/mild. However, some patients may develop critical forms. We aimed to describe characteristics and evaluate the factors associated to in-hospital mortality of patients with critical COVID-19/MIS-C in the Amazonian region. This multicenter prospective cohort included critically ill children (1 mo-18 years old), with confirmed COVID-19/MIS-C admitted to 3 tertiary Pediatric Intensive Care Units (PICU) in the Brazilian Amazon, between April/2020 and May/2023. The main outcome was in-hospital mortality and were evaluated using a multivariable Cox proportional regression. We adjusted the model for pediatric risk of mortality score version IV (PRISMIV) score and age/comorbidity. 266 patients were assessed with 187 in the severe COVID-19 group, 79 included in the MIS-C group. In the severe COVID-19 group 108 (57.8%) were male, median age was 23 months, 95 (50.8%) were up to 2 years of age. Forty-two (22.5%) patients in this group died during follow-up in a median time of 11 days (IQR, 2-28). In the MIS-C group, 56 (70.9%) were male, median age was 23 months and median follow-up was 162 days (range, 3-202). Death occurred in 17 (21.5%) patients with a median death time of 7 (IQR, 4-13) days. The mortality was associated with higher levels of Vasoactive Inotropic-Score (VIS), presence of acute respiratory distress syndrome (ARDS), higher levels of Erythrocyte Sedimentation Rate, (ESR) and thrombocytopenia. Critically ill patients with severe COVID-19 and MIS-C from the Brazilian Amazon showed a high mortality rate, within 12 days of hospitalization.

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.

COVID-19 cooling: Nanostrategies targeting cytokine storm for controlling severe and critical symptoms

As severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants continue to wreak havoc worldwide, the "Cytokine Storm" (CS, also known as the inflammatory storm) or Cytokine Release Syndrome has reemerged in the public consciousness. CS is a significant contributor to the deterioration of infected individuals. Therefore, CS control is of great significance for the treatment of critically ill patients and the reduction of mortality rates. With the occurrence of variants, concerns regarding the efficacy of vaccines and antiviral drugs with a broad spectrum have grown. We should make an effort to modernize treatment strategies to address the challenges posed by mutations. Thus, in addition to the requirement for additional clinical data to monitor the long-term effects of vaccines and broad-spectrum antiviral drugs, we can use CS as an entry point and therapeutic target to alleviate the severity of the disease in patients. To effectively combat the mutation, new technologies for neutralizing or controlling CS must be developed. In recent years, nanotechnology has been widely applied in the biomedical field, opening up a plethora of opportunities for CS. Here, we put forward the view of cytokine storm as a therapeutic target can be used to treat critically ill patients by expounding the relationship between coronavirus disease 2019 (COVID-19) and CS and the mechanisms associated with CS. We pay special attention to the representative strategies of nanomaterials in current neutral and CS research, as well as their potential chemical design and principles. We hope that the nanostrategies described in this review provide attractive treatment options for severe and critical COVID-19 caused by CS.

Baseline Echocardiography and Laboratory Findings in MIS-C and Associations with Clinical Illness Severity

Children with COVID-associated multisystem inflammatory syndrome (MIS-C) may develop severe disease. We explored the association of admission echocardiographic and laboratory parameters with MIS-C disease severity. This retrospective, single center study of consecutive MIS-C patients (4/2020-12/2021) excluded those with preexisting cardiomyopathy, congenital heart disease, or prior cardiotoxic therapy. Our hypothesis was that worse admission echocardiographic and laboratory parameters were associated with more severe disease based on vasoactive medication use. Univariable and multivariable logistic regression models assessed the association between vasoactive medication use and baseline variables. Of 118 MIS-C patients, median age was 7.8 years (IQR 4.6, 11.8), 48% received vasoactive medication. Higher admission brain natriuretic peptide [OR 1.07 (95% CI 1.02,1.14), p = 0.019], C-reactive protein [OR 1.08 (1.03,1.14), p = 0.002], troponin [OR 1.05 (1.02,1.1), p = 0.015]; lower left ventricular ejection fraction [LVEF, OR 0.96 (0.92,1), p = 0.042], and worse left atrial reservoir strain [OR 0.96 (0.92,1), p = 0.04] were associated with vasoactive medication use. Only higher CRP [OR 1.07 (1.01, 1.11), p = 0.034] and lower LVEF [0.91 (0.84,0.98), p = 0.015] remained independently significant. Among those with normal admission LVEF (78%, 92/118), 43% received vasoactive medication and only higher BNP [OR 1.09 (1.02,1.19), p = 0.021 per 100 pg/mL] and higher CRP [OR 1.07 (1.02,1.14), p = 0.013] were associated with use of vasoactive medication. Nearly half of all children admitted for MIS-C subsequently received vasoactive medication, including those admitted with a normal LVEF. Similarly, admission strain parameters were not discriminatory. Laboratory markers of systemic inflammation and cardiac injury may better predict early MIS-C disease severity.

Treatment of Acute COVID-19 and COVID-19 Exposures in Children and Adolescents

ABSTRACT

The landscape of acute COVID-19 therapeutics has dramatically evolved since the onset of the pandemic. The treatment of acute COVID-19 in children and adolescents requires knowledge of risk factors and clinical features to appropriately select antiviral and immunomodulatory therapies. This review article provides updated guidance for emergency physicians in the treatment of acute COVID-19 in children and adolescents.

A Tale of a Trail on How It Takes 5 Days of Kawasaki Disease to Initiate Coronary Artery Injury and Change the Lives of Children

Many articles written on Kawasaki disease explain the disease and the history of an acute inflammatory dysregulation that typically affects preschool children and does not spare older ones. Six decades have passed since the discovery of the disease in Japan, yet there are parts of the world where the disease passes unacknowledged, diagnosis is delayed, or basic treatments are not readily available. The burden of Kawasaki disease is on every health-care provider who attends to children's health. It takes 5 days for the disease to initiate coronary artery injury in a child's heart, compared to 5 decades of lifetime atherosclerosis. Challenges facing patients, families, and physicians may not be overcome unless we advocate for the disease recognition and seek support for affordable, timely treatment, impactful research, and dissemination of knowledge. The purpose of this review is to provide a comprehensive review of the history of Kawasaki disease and how it has affected children's health worldwide over the last 6 decades. The review also raises current challenges facing the fight against Kawasaki disease. In an effort to bring Kawasaki disease advocates together in a landing zone, an internet hub for Kawasaki disease experts and enthusiasts has been created: the International Kawasaki Disease Society (presently a concept idea) and a dedicated website, www.ikds-org.

Adverse effects of remdesivir for the treatment of acute COVID-19 in the pediatric population: a retrospective observational study

BACKGROUND

Although the severity of coronavirus disease 2019 (COVID-19) tends to be lower in children, it can still lead to severe illness, particularly among those with chronic medical conditions. While remdesivir (RDV) is one of the few approved antiviral treatments for COVID-19 in children in many countries, the available data on the safety of RDV in this population is limited.

METHODS

To address this knowledge gap, a multicenter study involving 65 patients retrospectively analyzed the clinical data from individuals aged <18 who were hospitalized due to severe COVID-19 (defined as SpO2 < 94% or requiring supplemental oxygen) and received at least one dose of RDV. Additionally, the study encompassed 22 patients with mild-moderate COVID-19 who were considered at high risk of developing severe disease.

RESULTS

Nineteen children (29%) experienced mild-to-moderate adverse events (AEs) attributed to RDV, including transaminitis in 20% of children, bradycardia in 8%, and hypotension in 5%. AEs did not require discontinuation of RDV, except in one patient who developed premature ventricular contractions. The rate of AEs did not differ between patients with severe COVID-19 and those with mild-moderate COVID-19 but at high risk for severe disease. All but one patient were discharged within 23 days of admission, and no fatalities were recorded. Among high-risk patients with mild-moderate disease, only 2 (9%) progressed to the point of needing supplemental oxygen.

CONCLUSIONS

Our data suggests that RDV is safe in children, with no reported serious AEs. However, the absence of a control group limits the extent to which conclusions can be drawn. RDV may contribute to clinical improvement, particularly in high-risk patients.

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.

Navigating the Spectrum of Two Pediatric COVID-19 Complications: Multi-System Inflammatory Syndrome in Children and Post-Acute Sequelae of SARS-CoV-2 Infection

PURPOSE

This review summarizes the current scope of understanding associated with two common post-infectious complications associated with COVID-19 infection: Multi-System Inflammatory Syndrome in Children (MIS-C) and Post-Acute Sequelae of SARS-CoV-2 infection (PASC). It identifies current gaps in the knowledge and issues that may limit the ability to fill these gaps. This review provides a framework to drive continued research.

METHODS

A comprehensive review of the current literature was performed, identifying seminal articles describing the emergence of MIS-C and PASC, and works from the literature focused on the clinical implications and pathophysiologic understanding of these disorders.

FINDINGS

Although pediatric patients experienced few severe cases of acute COVID-19 infection, the burden of disease from post-infectious sequelae is substantial. Mortality is low, but morbidity is significant. There are still numerous unknowns about the pathophysiology of both MIS-C and PASC; however, with widespread immunity developing after increased vaccination and prior infection, it may be difficult to perform adequate prospective studies to answer pathophysiologic questions. Long-term sequalae of MIS-C seem to be minimal whereas, by definition, PASC is an ongoing problem and may be severe.

IMPLICATIONS

The rapid sharing of information regarding novel conditions such as MIS-C and PASC are key to interventions related to future post-infectious sequelae outside of those stemming from COVID-19. Although MIS-C seems unlikely to return as a clinical condition in substantial numbers, there is still significant learning that can be gleaned from existing patients about general aspects of epidemiology, equity, and pathophysiology. There is significant morbidity associated with PASC and additional resources need to be dedicated to determining appropriate and effective therapies moving forward.

The mechanisms of milder clinical symptoms of COVID-19 in children compared to adults

In stark contrast to adult patients, children who contract Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) typically manifest milder symptoms or remain asymptomatic. However, the precise underlying mechanisms of this pathogenesis remain elusive. In this review, we primarily retrospect the clinical characteristics of SARS-CoV-2 infection in children, and explore the factors that may contribute to the typically milder clinical presentation in pediatric Coronavirus Disease 2019 (COVID-19) patients compare with adults patients with COVID-19. The pathophysiological mechanisms that mitigate lung injury in children are as follows: the expression level of ACE2 receptor in children is lower; the binding affinity between ACE2 receptors and viral spike proteins in children was weaker; children have strong pre-activated innate immune response and appropriate adaptive immune response; children have more natural lymphocytes; children with COVID-19 can produce higher levels of IgM, IgG and interferon; children infected with SARS-CoV-2 can produce lower levels of IL-6 and IL-10; children have fewer underlying diseases and the lower risk of worsening COVID-19; children are usually exposed to other respiratory viruses and have an enhanced cross-reactive immunity. Comprehending the relative contributions of these processes to the protective phenotype in the developing lungs can help in the diagnosis, treatment and research pertaining to children with COVID-19.