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.

Extracorporeal Membrane Oxygenation in Children With COVID-19: A Systematic Review and Meta-Analysis.

OBJECTIVES: The indication, complications, and outcomes of extracorporeal membrane oxygenation (ECMO) in children with COVID-19-related illnesses remain unelucidated. Our study aimed to investigate the characteristics and outcomes of ECMO in children with COVID-19-related illnesses. DATA SOURCES: We searched PubMed and EMBASE databases in March 2022. STUDY SELECTION: We retrieved all studies involving children (age ≤ 18 yr) with COVID-19-related illnesses who received ECMO. DATA EXTRACTION: Two authors independently extracted data and assessed the risk of bias. Mortality, successful weaning rate, and complications while on ECMO were synthesized by a one-group meta-analysis using a random-effect model. Meta-regression was performed to explore the risk factors for mortality. DATA SYNTHESIS: We included 18 observational studies, four case series, and 22 case reports involving 110 children with COVID-19-related illnesses receiving ECMO. The median age was 8 years (range, 10 d to 18 yr), and the median body mass index was 21.4 kg/m 2 (range, 12.3-56.0 kg/m 2 ). The most common comorbidities were obesity (11% [7/63]) and congenital heart disease (11% [7/63]), whereas 48% (30/63) were previously healthy. The most common indications for ECMO were multisystem inflammatory syndrome in children (52% [47/90]) and severe acute respiratory distress syndrome (40% [36/90]). Seventy-one percent (56/79) received venoarterial-ECMO. The median ECMO runtime was 6 days (range, 3-51 d) for venoarterial ECMO and 11 days (range, 3-71 d) for venovenous ECMO. The mortality was 26.6% (95% CI, 15.9-40.9), and the successful weaning rate was 77.0% (95% CI, 55.4-90.1). Complications were seen in 37.0% (95% CI, 23.1-53.5) while on ECMO, including stroke, acute kidney injury, pulmonary edema, and thromboembolism. Corticosteroids and IV immunoglobulin therapies were associated with lower mortality. CONCLUSIONS: The mortality of children on ECMO for COVID-19 was relatively low. This invasive treatment can be considered as a treatment option for critically ill children with COVID-19.

Longitudinal Cardiac Outcomes of Multisystem Inflammatory Syndrome in Children: A Systematic Review and Meta-Analysis.

There is a paucity of longitudinal data on cardiac outcomes in multisystem inflammatory syndrome in children (MIS-C) associated with COVID-19. We aimed to investigate the longitudinal cardiovascular outcomes in MIS-C. PubMed and EMBASE were searched through May 2022. Observational studies were included, reporting mid-term (≥ 3 months) outcomes in children (aged < 21) with MIS-C. Data were extracted by two researchers. Longitudinal outcomes were synthesized by a one-group meta-analysis using a random-effects model. Eleven studies with a follow-up period (3 months to 1 year) were identified, including 547 MIS-C patients. The mortality was 2.5% (95% CI 1.3-4.9). The majority of left ventricular (LV) systolic dysfunction present in 46.8% (95% CI 32.7-61.3) in the acute phase resolved by 3 months, and the prevalence of LV systolic dysfunction was 1.7% (95% CI 0.5-5.7) and 2.1% (95% CI 0.8-5.4) at 3 month and 6 month follow-up, respectively. Additionally, the persistent LV systolic dysfunction in the small population was mild. However, coronary abnormalities such as coronary artery dilatation or aneurysms, seen in 23.7% (95% CI 17.7-31.1) at baseline, persisted in 4.7% (95% CI 1.5-14.3) at 3 months and 5.2% (95% CI 3.0-8.9) at 6 months. Mitral regurgitation (MR), which was observed in 56.6% (95% CI 27.7-81.6) at baseline, also persisted in 7.5% at 6 months. In conclusion, our study demonstrated largely favorable cardiac outcomes, suggesting resolution of LV systolic dysfunction in the majority of cases. However, coronary abnormalities and MR persisted in a subset of patients at mid-term follow-up.

Protective effect of COVID-19 vaccination against long COVID syndrome: A systematic review and meta-analysis.

BACKGROUND: The relationship between coronavirus disease 2019 (COVID-19) vaccination and long COVID has not been firmly established. We conducted a systematic review and meta-analysis to evaluate the association between COVID-19 vaccination and long COVID. METHODS: PubMed and EMBASE databases were searched on September 2022 without language restrictions (CRD42022360399) to identify prospective trials and observational studies comparing patients with and without vaccination before severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. We also included studies reporting symptomatic changes of ongoing long COVID following vaccination among those with a history of SARS-CoV-2 infection. Odds ratios (ORs) for each outcome were synthesized using a random-effects model. Symptomatic changes after vaccination were synthesized by a one-group meta-analysis. RESULTS: Six observational studies involving 536,291 unvaccinated and 84,603 vaccinated (before SARS-CoV-2 infection) patients (mean age, 41.2-66.6; female, 9.0-67.3%) and six observational studies involving 8,199 long COVID patients (mean age, 40.0 to 53.5; female, 22.2-85.9%) who received vaccination after SARS-CoV-2 infection were included. Two-dose vaccination was associated with a lower risk of long COVID compared to no vaccination (OR, 0.64; 95% confidence interval [CI], 0.45-0.92) and one-dose vaccination (OR, 0.60; 95% CI, 0.43-0.83). Two-dose vaccination compared to no vaccination was associated with a lower risk of persistent fatigue (OR, 0.62; 95% CI, 0.41-0.93) and pulmonary disorder (OR, 0.50; 95% CI, 0.47-0.52). Among those with ongoing long COVID symptoms, 54.4% (95% CI, 34.3-73.1%) did not report symptomatic changes following vaccination, while 20.3% (95% CI, 8.1-42.4%) experienced symptomatic improvement after two weeks to six months of COVID-19 vaccination. CONCLUSIONS: COVID-19 vaccination before SARS-CoV-2 infection was associated with a lower risk of long COVID, while most of those with ongoing long COVID did not experience symptomatic changes following vaccination.

Myopericarditis After COVID-19 mRNA Vaccination Among Adolescents and Young Adults: A Systematic Review and Meta-analysis.

Importance: Published data on COVID-19 mRNA vaccine-associated myopericarditis in adolescents and young adults have been derived from small case series, national population-based studies, or passive reporting systems. Pooled evidence from a larger, international cohort is scarce. Objective: To investigate the clinical features and early outcomes associated with myopericarditis after COVID-19 mRNA vaccination in a heterogeneous population of adolescents and young adults. Data Sources: PubMed and EMBASE were searched through August 2022. Language restrictions were not applied. Study Selection: Observational studies and case series describing COVID-19 vaccine-associated myopericarditis in adolescents and young adults aged 12 to 20 years and reporting clinical characteristics and early outcomes were included. Data Extraction and Synthesis: Two independent investigators extracted relevant data from each study. One-group meta-analysis in a random effects model was performed. The Preferred Reporting Items for Systematic Reviews and Meta-analysis and Meta-analysis of Observational Studies in Epidemiology reporting guidelines were followed. Main Outcomes and Measures: The primary outcomes were clinical features and early outcomes for COVID-19 mRNA vaccine-associated myopericarditis, including incident rate, cardiac findings, hospitalization, intensive care unit (ICU) admission, and in-hospital mortality. Results: A total of 23 observational studies were identified, including 854 individuals (mean age, 15.9 [95% CI, 15.5-16.2] years) with COVID-19 vaccine-associated myopericarditis. Male sex was predominant, at 90.3% (95% CI, 87.3%-93.2%) of individuals. The incident rate was higher after the second dose than the first dose, with 74.4% (95% CI, 58.2%-90.5%) of events occurring after the second dose. Most patients (84.4% [95% CI, 80.5%-88.3%] of patients) had preserved left ventricular (LV) function. Of the 15.6% (95% CI, 11.7%-19.5%) of patients with LV systolic dysfunction (LV ejection fraction [LVEF] <55%), most (14.1% [95% CI, 10.2%-18.1%]) were mild (ie, LVEF 45%-54%), and only 1.3% (95% CI, 0%-2.6%) of patients had severe LV systolic dysfunction (ie, LVEF<35%). Interestingly, cardiac magnetic resonance imaging revealed late gadolinium enhancement in 87.2% (95% CI, 79.8%-94.7%) of patients. Although 92.6% (95% CI, 87.8%-97.3%) of patients were hospitalized and 23.2% (95% CI, 11.7%-34.7%) of patients required ICU admission, inotropes were used in only 1.3% (95% CI, 0%-2.7%) of patients, no patients died or required mechanical support, and the hospital length of stay was 2.8 (95% CI, 2.1-3.5) days. Conclusions and Relevance: This systematic review and meta-analysis found low incidence rate and largely favorable early outcomes of COVID-19 mRNA vaccine-associated myopericarditis in adolescents and young adults from a wide range of populations. These findings are reassuring but continued follow-up is warranted.

Assessment of Efficacy and Safety of mRNA COVID-19 Vaccines in Children Aged 5 to 11 Years: A Systematic Review and Meta-analysis.

Importance: Evidence of the efficacy and safety of messenger RNA (mRNA) COVID-19 vaccines in children aged 5 to 11 years has been emerging. Collecting these data will inform clinicians, families, and policy makers. Objective: To evaluate the efficacy and safety of mRNA COVID-19 vaccines in children aged 5 to 11 years in a systematic review and meta-analysis. Data Sources: PubMed and Embase databases were searched on September 29, 2022, without language restrictions. Study Selection: Randomized clinical trials and observational studies comparing vaccinated vs unvaccinated children aged 5 to 11 years and reporting efficacy or safety outcomes were included. Studies reporting safety outcomes in vaccinated children only (ie, no control group) were also included. Data Extraction and Synthesis: Two investigators independently extracted relevant data from each study. Odds ratios (ORs) for efficacy and safety outcomes and incidences of adverse events (AEs) following vaccination were synthesized using a random-effects model. This study followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses and Meta-analysis of Observational Studies in Epidemiology reporting guidelines. Main Outcomes and Measures: The primary outcome was SARS-CoV-2 infections with or without symptoms. The secondary outcomes included symptomatic SARS-CoV-2 infections, hospitalizations, and multisystem inflammatory syndrome in children. The incidences of each AE following vaccination were also evaluated. Results: Two randomized clinical trials and 15 observational studies involving 10 935 541 vaccinated children (median or mean age range, 8.0-9.5 years) and 2 635 251 unvaccinated children (median or mean age range, 7.0-9.5 years) were included. Two-dose mRNA COVID-19 vaccination compared with no vaccination was associated with lower risks of SARS-CoV-2 infections with or without symptoms (OR, 0.47; 95% CI, 0.35-0.64), symptomatic SARS-CoV-2 infections (OR, 0.53; 95% CI, 0.41-0.70), hospitalizations (OR, 0.32; 95% CI, 0.15-0.68), and multisystem inflammatory syndrome in children (OR, 0.05; 95% CI, 0.02-0.10). Two randomized clinical trials and 5 observational studies investigated AEs among vaccinated children. Most vaccinated children experienced at least 1 local AE following the first injection (32 494 of 55 959 [86.3%]) and second injection (28 135 of 46 447 [86.3%]). Vaccination was associated with a higher risk of any AEs compared with placebo (OR, 1.92; 95% CI, 1.26-2.91). The incidence of AEs that prevented normal daily activities was 8.8% (95% CI, 5.4%-14.2%) and that of myocarditis was estimated to be 1.8 per million (95% CI, 0.000%-0.001%) following the second injection. Conclusions and Relevance: In this systematic review and meta-analysis, COVID-19 mRNA vaccines among children aged 5 to 11 years were associated with measures of efficacy in preventing SARS-CoV-2 infection and severe COVID-19-related illnesses. While most children developed local AEs, severe AEs were rare, and most of AEs resolved within several days. These data provide evidence for future recommendations.

Peripartum Outcomes Associated With COVID-19 Vaccination During Pregnancy: A Systematic Review and Meta-analysis.

Importance: The risk and benefits of COVID-19 vaccination during pregnancy are under investigation. Pooled evidence regarding neonatal and maternal outcomes in association with COVID-19 vaccination during pregnancy is scarce. Objective: To evaluate the association between COVID-19 vaccination during pregnancy and peripartum outcomes. Data Sources: PubMed and EMBASE databases were searched on April 5, 2022. Language restrictions were not applied. Study Selection: Prospective trials and observational studies comparing the individuals who received at least 1 COVID-19 vaccination during pregnancy with those who did not and reporting the neonatal outcomes, including preterm birth, small for gestational age, low Apgar score, neonatal intensive care units (NICU) admission, and intrauterine fetal death (IFD). Data Extraction and Synthesis: Two independent investigators extracted relevant data from each study. Odds ratios (ORs) were calculated using a random-effects model. This study followed the Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines. Main Outcomes and Measures: The primary outcomes were the neonatal outcomes, including preterm birth, small for gestational age, low Apgar score, NICU admission, and IFD. The secondary outcomes were maternal outcomes, including maternal SARS-CoV-2 infection, cesarean delivery, postpartum hemorrhage, and chorioamnionitis. Results: Nine observational studies involving 81 349 vaccinated (mean age, 32-35 years) and 255 346 unvaccinated individuals during pregnancy (mean age, 29.5-33 years) were included. COVID-19 vaccination during pregnancy was associated with lower risk of NICU admission (OR, 0.88; 95% CI, 0.80-0.97) and IFD (OR, 0.73; 95% CI, 0.57-0.94), whereas there was no statistically significant association with preterm birth (OR, 0.89; 95% CI, 0.76-1.04), small for gestational age (OR, 0.99; 95% CI, 0.94-1.04), and low Apgar score (OR, 0.94; 95% CI, 0.87-1.02). COVID-19 vaccination during pregnancy was associated with a lower risk of maternal SARS-CoV-2 infection (OR, 0.46; 95% CI, 0.22-0.93), whereas it was not associated with increased risk of cesarean delivery (OR, 1.05; 95% CI, 0.93-1.20), postpartum hemorrhage (OR, 0.95; 95% CI, 0.83-1.07), and chorioamnionitis (OR, 0.95; 95% CI, 0.83-1.07). Conclusions and Relevance: COVID-19 vaccination during pregnancy was not associated with an increase in the risk of peripartum outcomes, was associated with a decreased risk of NICU admission, IFD, and maternal SARS-CoV-2 infection. Thus, COVID-19 vaccination should be encouraged for pregnant individuals.

COVID-19 and multisystem inflammatory syndrome in children: A systematic review and meta-analysis.

BACKGROUND: Multisystem inflammatory syndrome in children (MIS-C) associated with coronavirus disease 2019 has been increasingly recognized. However, the clinical features of MIS-C and the differences from Kawasaki disease remain unknown. The study aims to investigate the epidemiology and clinical course of MIS-C. METHODS: PubMed and EMBASE were searched through August 30, 2020. Observational studies describing MIS-C were included. Data regarding demographic features, clinical symptoms, laboratory, echocardiography and radiology findings, treatments, and outcomes were extracted. Study-specific estimates were combined using one-group meta-analysis in a random-effects model. RESULTS: A total of 27 studies were identified including 917 MIS-C patients. The mean age was 9.3 (95% confidence interval [CI], 8.4-10.1). The pooled proportions of Hispanic and Black cases were 34.6% (95% CI, 28.3-40.9) and 31.5% (95% CI, 24.8-38.1), respectively. The common manifestations were gastrointestinal symptoms (87.3%; 95% CI, 82.9-91.6) and cardiovascular involvement such as myocardial dysfunction (55.3%; 95% CI, 42.4-68.2), coronary artery aneurysms (21.7%; 95% CI, 12.8-30.1) and shock (65.8%; 95% CI, 51.1-80.4), with marked elevated inflammatory and cardiac markers. The majority of patients received intravenous immunoglobulin (81.0%; 95% CI, 75.0-86.9), aspirin (67.3%; 95% CI, 48.8-85.7), and corticosteroids (63.6%; 95% CI, 53.4-73.8) with a variety of anti-inflammatory agents. Although myocardial dysfunction improved in 55.1% (95% CI, 33.4-76.8) at discharge, the rate of extracorporeal membrane oxygenation use was 6.3% (95% CI, 2.8-9.8) and the mortality was 1.9% (95% CI, 1.0-2.8). CONCLUSION: Our findings suggest that MIS-C leads to multiple organ failure, including gastrointestinal manifestations, myocardial dysfunction and coronary abnormalities, and has distinct features from Kawasaki disease.

Clinical characteristics of COVID-19 in children: A systematic review.

BACKGROUND: Limited pediatric cases with coronavirus disease 2019 (COVID-19) have been reported and the clinical profiles regarding COVID-19 in children remain obscure. Our aim was to investigate the clinical characteristics of COVID-19 in children. METHODS: PUBMED and EMBASE were searched through 20 June 2020, for case reports and case series reporting pediatric COVID-19 cases. Epidemiological, clinical, laboratory, and radiological data were collected and analyzed to compare by age. RESULTS: Our search identified 46 eligible case reports and case series. A total of 114 pediatric cases with COVID-19 were included. The main clinical features were mild symptoms including fever (64%), cough (35%), and rhinorrhea (16%), or no symptoms (15%). Ground-like opacities were common radiological findings (54%). The main laboratory findings were lymphopenia (33%) and elevated D-dimer (52%) and C-reactive protein (40%) levels. We identified 17 patients (15%) with multisystem inflammatory syndrome in children (MIS-C) manifesting with symptoms overlapping with, but distinct from, Kawasaki disease, including gastrointestinal symptoms, left ventricular systolic dysfunction, shock, and marked elevated inflammatory biomarkers. Twelve percent of the patients including 65% of the MIS-C cases required intensive care because of hypotension. No deaths were reported. CONCLUSION: This systematic review found that children with COVID-19 are generally less severe or asymptomatic. However, infants might be seriously ill and older children might develop MIS-C with severe illness. Early detection of children with mild symptoms or an asymptomatic state and early diagnosis of MIS-C are mandatory for the management of COVID-19 and the prevention of transmission and a severe inflammatory state.