COVID-19 Vaccine Reactogenicity and Vaccine Attitudes Among Children and Parents/Guardians After Multisystem Inflammatory Syndrome in Children or COVID-19 Hospitalization: September 2021-May 2022.

BACKGROUND: Multisystem inflammatory syndrome in children (MIS-C) is a multiorgan hyperinflammatory condition following SARS-CoV-2 infection. Data on COVID-19 vaccine adverse events and vaccine attitudes in children with prior MIS-C are limited. We described characteristics associated with COVID-19 vaccination, vaccine adverse events and vaccine attitudes in children with a history of MIS-C or COVID-19 and their parents/guardians. METHODS: We enrolled children previously hospitalized for MIS-C or COVID-19 from 3 academic institutions. We abstracted charts and interviewed children and parents/guardians regarding vaccine adverse events and acceptability. RESULTS: Of 163 vaccine-eligible children enrolled with a history of MIS-C and 70 with history of COVID-19, 51 (31%) and 34 (49%), respectively, received mRNA COVID-19 vaccine a median of 10 (Interquartile Range 6-13) months after hospital discharge. Among 20 children with MIS-C and parents/guardians who provided interviews, local injection site reaction of brief duration (mean 1.8 days) was most commonly reported; no children required medical care within 2 weeks postvaccination. Vaccine survey results of interviewed, vaccinated children and their parents/guardians: of 20 children with MIS-C and 15 children with COVID-19, 17 (85%) and 13 (87%), respectively, listed doctors in the top 3 most trusted sources for vaccine information; 13 (65%) and 9 (60%) discussed vaccination with their doctor. CONCLUSIONS: COVID-19 vaccination was well tolerated in children with prior MIS-C or COVID-19 participating in our investigation. Parents/guardians regarded their children's doctors as a trusted source of information for COVID-19 vaccines, and most vaccinated children's parents/guardians had discussed COVID-19 vaccination for their child with their doctor.

Council of State and Territorial Epidemiologists/CDC Surveillance Case Definition for Multisystem Inflammatory Syndrome in Children Associated with SARS-CoV-2 Infection - United States.

This report summarizes the evidence and rationale supporting the components of the CSTE/CDC MIS-C surveillance case definition and describes the methods used to develop the definition. These methods included convening MIS-C clinical experts (i.e., consultants): regarding identification of MIS-C and its distinction from other pediatric conditions, a review of available literature comparing MIS-C phenotype with that of pediatric COVID-19 and other hyperinflammatory syndromes, and retrospective application of different criteria to data from MIS-C cases previously reported to CDC.

Multisystem Inflammatory Syndrome in Adults After Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection and Coronavirus Disease 2019 (COVID-19) Vaccination.

BACKGROUND: Multisystem inflammatory syndrome in adults (MIS-A) was reported in association with the coronavirus disease 2019 (COVID-19) pandemic. MIS-A was included in the list of adverse events to be monitored as part of the emergency use authorizations issued for COVID-19 vaccines. METHODS: Reports of MIS-A patients received by the Centers for Disease Control and Prevention (CDC) after COVID-19 vaccines became available were assessed. Data collected on the patients included clinical and demographic characteristics and their vaccine status. The Vaccine Adverse Events Reporting System (VAERS) was also reviewed for possible cases of MIS-A. RESULTS: From 14 December 2020 to 30 April 2021, 20 patients who met the case definition for MIS-A were reported to CDC. Their median age was 35 years (range, 21-66 years), and 13 (65%) were male. Overall, 16 (80%) patients had a preceding COVID-19-like illness a median of 26 days (range 11-78 days) before MIS-A onset. All 20 patients had laboratory evidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Seven MIS-A patients (35%) received COVID-19 vaccine a median of 10 days (range, 6-45 days) before MIS-A onset; 3 patients received a second dose of COVID-19 vaccine 4, 17, and 22 days before MIS-A onset. Patients with MIS-A predominantly had gastrointestinal and cardiac manifestations and hypotension or shock. CONCLUSIONS: Although 7 patients were reported to have received COVID-19 vaccine, all had evidence of prior SARS-CoV-2 infection. Given the widespread use of COVID-19 vaccines, the lack of reporting of MIS-A associated with vaccination alone, without evidence of underlying SARS-CoV-2 infection, is reassuring.

Trends in Treatments for Multisystem Inflammatory Syndrome in Children (MIS-C), United States, February 2020 - July 2021.

BACKGROUND: Multisystem inflammatory syndrome in children (MIS-C) is a novel severe postinfectious condition associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The purpose of this report is to describe nationwide trends in the evolving clinical management of MIS-C. METHODS: Patients with MIS-C were reported from state and local jurisdictions to the Centers for Disease Control and Prevention's (CDC's) MIS-C national surveillance system. Patients' case reports were reviewed to ensure that they met the CDC MIS-C case definition and had sufficient data for analysis. The prevalence of use of treatments for MIS-C, temporal trends in use of these treatments, and frequency of administration of different treatment combinations were analyzed. RESULTS: There were 4470 patients meeting the MIS-C case definition with onset dates from 19 February 2020 to 31 July 2021. The proportion of patients admitted to an intensive care unit (ICU) has declined over time, from 78.7% in April 2020 to 57.5% in June 2021 (P = .001). The most common treatments were intravenous immunoglobulin (IVIG), given to 85.6% of patients; steroids (77.7%), and antiplatelet medications (73.7%); use of each of these treatments has increased over time, particularly in patients not requiring admission to an ICU (all P < .001). Older patients and non-Hispanic Black patients were more likely to receive additional modes of therapy including vasoactive medication, noninvasive respiratory support, anticoagulation medication, and intubation/mechanical ventilation. CONCLUSIONS: IVIG, steroids, and antiplatelet medication have become increasingly utilized as standard treatment for MIS-C patients, while the use of other treatments may be contingent on the type and severity of clinical findings.

Serologic and Cytokine Signatures in Children With Multisystem Inflammatory Syndrome and Coronavirus Disease 2019.

BACKGROUND: The serologic and cytokine responses of children hospitalized with multisystem inflammatory syndrome (MIS-C) vs coronavirus disease 2019 (COVID-19) are poorly understood. METHODS: We performed a prospective, multicenter, cross-sectional study of hospitalized children who met the Centers for Disease Control and Prevention case definition for MIS-C (n = 118), acute COVID-19 (n = 88), or contemporaneous healthy controls (n = 24). We measured severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike receptor-binding domain (RBD) immunoglobulin G (IgG) titers and cytokine concentrations in patients and performed multivariable analysis to determine cytokine signatures associated with MIS-C. We also measured nucleocapsid IgG and convalescent RBD IgG in subsets of patients. RESULTS: Children with MIS-C had significantly higher SARS-CoV-2 RBD IgG than children with acute COVID-19 (median, 2783 vs 146; P < .001), and titers correlated with nucleocapsid IgG. For patients with MIS-C, RBD IgG titers declined in convalescence (median, 2783 vs 1135; P = .010) in contrast to patients with COVID-19 (median, 146 vs 4795; P < .001). MIS-C was characterized by transient acute proinflammatory hypercytokinemia, including elevated levels of interleukin (IL) 6, IL-10, IL-17A, and interferon gamma (IFN-γ). Elevation of at least 3 of these cytokines was associated with significantly increased prevalence of prolonged hospitalization ≥8 days (prevalence ratio, 3.29 [95% CI, 1.17-9.23]). CONCLUSIONS: MIS-C was associated with high titers of SARS-CoV-2 RBD IgG antibodies and acute hypercytokinemia with IL-6, IL-10, IL-17A, and IFN-γ.

Multisystem Inflammatory Syndrome in Children-United States, February 2020-July 2021.

BACKGROUND: Multisystem inflammatory syndrome in children (MIS-C) is a severe hyperinflammatory condition in persons aged <21 years associated with antecedent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Our objective was to describe MIS-C cases reported to Centers for Disease Control and Prevention's (CDC's) national surveillance since the coronavirus disease 2019 (COVID-19) pandemic began. METHODS: We included patients meeting the MIS-C case definition with onset date from 19 February 2020 through 31 July 2021, using CDC's MIS-C case report form, which collects information on demographics, clinical presentation, and laboratory results. Trends over time across 3 MIS-C pandemic waves were assessed using Cochran-Armitage test for categorical and Jonckheere-Terpstra test for continuous variables. RESULTS: Of 4901 reported cases, 4470 met inclusion criteria. Median patient age increased over time (P < .001), with a median of 9 years (interquartile range, 5-13 years) during the most recent (third) wave. Male predominance also increased (62% in third wave, P < .001). A significant (P < .001) increase in severe hematologic and gastrointestinal involvement was observed across the study period. Frequency of several cardiovascular complications (ie, cardiac dysfunction, myocarditis, and shock/vasopressor receipt) and renal failure declined (P < .001). Provision of critical care including mechanical ventilation (P < .001) and extracorporeal membrane oxygenation (ECMO; P = .046) decreased, as did duration of hospitalization and mortality (each P < .001). CONCLUSIONS: Over the first 3 pandemic waves of MIS-C in the United States, cardiovascular complications and clinical outcomes including length of hospitalization, receipt of ECMO, and death decreased over time. These data serve as a baseline for monitoring future trends associated with SARS-CoV-2 B.1.617.2 (Delta) or other variants and increased COVID-19 vaccination among children.

Clinical Characteristics of Multisystem Inflammatory Syndrome in Adults: A Systematic Review.

IMPORTANCE: Multisystem inflammatory syndrome in adults (MIS-A) has not been well described. Improved diagnosis and treatment of MIS-A might mitigate COVID-19 morbidity and mortality. OBJECTIVE: To summarize the descriptive epidemiology and clinical characteristics of MIS-A. EVIDENCE REVIEW: This systematic review identified patients with MIS-A using 3 strategies: (1) literature review from May 1, 2020, to May 25, 2021, by searching MEDLINE, Embase, Global Health, CAB Abstracts, PsycINFO, CINAHL (Cumulative Index to Nursing and Allied Health Literature), Academic Search Complete, Scopus, World Health Organization Global COVID-19 Literature Database, and Google Scholar; (2) voluntary reports of MIS-A to the Centers for Disease Control and Prevention (CDC); and (3) reports among persons aged 18 to 20 years in the CDC surveillance system for MIS in children. FINDINGS: Of 221 patients with MIS-A, the median age was 21 (interquartile range [IQR], 19-34) years, and 154 of 219 (70%) with data available were men. Sixty of 169 patients (36%) were non-Hispanic Black individuals, and 122 of 209 (58%) had no underlying comorbidity. One hundred two of 149 patients (68%) noted a previous symptomatic COVID-19-like illness (median, 28 [IQR, 20-36] days previously). Most patients with MIS-A presented with fever (197 of 205 [96%]), hypotension (133 of 220 [60%]), cardiac dysfunction (114 of 210 [54%]), shortness of breath (102 of 198 [52%]), and/or diarrhea (102 of 197 [52%]). The median number of organ systems involved was 5 (IQR, 4-6). Median hospital stay was 8 (IQR, 5-12) days; 115 of 201 patients (57%) were admitted to the intensive care unit; 101 of 213 (47%) required respiratory support, and 15 of 220 (7%) died. Most patients (176 of 195 [90%]) had elevated markers of coagulopathy and/or inflammation and a positive SARS-CoV-2 serologic finding (139 of 194 [72%]). Ten patients with MIS-A presented with Kawasaki disease. CONCLUSIONS AND RELEVANCE: These findings suggest that MIS-A is a serious hyperinflammatory condition that presents approximately 4 weeks after onset of acute COVID-19 with extrapulmonary multiorgan dysfunction.

Racial and Ethnic Disparities in Multisystem Inflammatory Syndrome in Children in the United States, March 2020 to February 2021.

BACKGROUND: The incidence of multisystem inflammatory syndrome in children (MIS-C) varies by race and ethnicity. This study assessed whether disparities in MIS-C in the United States by race and ethnicity exceed known disparities in coronavirus disease 2019 (COVID-19) incidence. METHODS: We compared the distribution of race and ethnicity among patients with MIS-C (<21 years of age, termed children) with onset March 2020 to February 2021 to that of children with COVID-19 and in the general population. Analysis was restricted to 369 counties with high completeness of race and ethnicity reporting for MIS-C and COVID-19. For each racial and ethnic group, observed numbers of patients with MIS-C were compared with expected numbers (observed/expected ratio) in children with COVID-19 and in the general population within these counties. RESULTS: Compared with children in the general population, MIS-C was more frequent among Hispanic (139% of expected) and non-Hispanic Black children (183%) and less frequent among non-Hispanic White (64%) and non-Hispanic Asian children (48%). Compared with children with COVID-19, MIS-C was more frequent in non-Hispanic Black children (207% of expected) and less frequent in non-Hispanic White children (68%); however, frequency was not different among Hispanic (102%) and non-Hispanic Asian (74%) children. CONCLUSIONS: Disparities in MIS-C by race and ethnicity exist, even after controlling for COVID-19 disparities and geographic variations. The high proportion of MIS-C among Hispanic children and low proportion among non-Hispanic Asian children align with COVID-19 rates, while the high proportion among non-Hispanic Black children and low proportion among non-Hispanic White children are not explainable by COVID-19 rates.

Multisystem Inflammatory Syndrome in Infants <12 months of Age, United States, May 2020-January 2021.

BACKGROUND: Multisystem inflammatory syndrome in children (MIS-C), temporally associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has been identified in infants <12 months old. Clinical characteristics and follow-up data of MIS-C in infants have not been well described. We sought to describe the clinical course, laboratory findings, therapeutics and outcomes among infants diagnosed with MIS-C. METHODS: Infants of age <12 months with MIS-C were identified by reports to the CDC's MIS-C national surveillance system. Data were obtained on clinical signs and symptoms, complications, treatment, laboratory and imaging findings, and diagnostic SARS-CoV-2 testing. Jurisdictions that reported 2 or more infants were approached to participate in evaluation of outcomes of MIS-C. RESULTS: Eighty-five infants with MIS-C were identified and 83 (97.6%) tested positive for SARS-CoV-2 infection; median age was 7.7 months. Rash (62.4%), diarrhea (55.3%) and vomiting (55.3%) were the most common signs and symptoms reported. Other clinical findings included hypotension (21.2%), pneumonia (21.2%) and coronary artery dilatation or aneurysm (13.9%). Laboratory abnormalities included elevated C-reactive protein, ferritin, d-dimer and fibrinogen. Twenty-three infants had follow-up data; 3 of the 14 patients who received a follow-up echocardiogram had cardiac abnormalities during or after hospitalization. Nine infants had elevated inflammatory markers up to 98 days postdischarge. One infant (1.2%) died after experiencing multisystem organ failure secondary to MIS-C. CONCLUSIONS: Infants appear to have a milder course of MIS-C than older children with resolution of their illness after hospital discharge. The full clinical picture of MIS-C across the pediatric age spectrum is evolving.

Trends in Geographic and Temporal Distribution of US Children With Multisystem Inflammatory Syndrome During the COVID-19 Pandemic.

Importance: Multiple inflammatory syndrome in children (MIS-C) occurs in association with the COVID-19 pandemic. Objective: To describe the clinical characteristics and geographic and temporal distribution of the largest cohort of patients with MIS-C in the United States to date. Design, Setting, and Participants: Cross-sectional analysis was conducted on clinical and laboratory data collected from patients with MIS-C. The analysis included patients with illness onset from March 2020 to January 2021 and met MIS-C case definition. Main Outcomes and Measures: Geographic and temporal distribution of MIS-C was compared with that of COVID-19 nationally, by region, and level of urbanicity by county. Clinical and laboratory findings and changes over time were described by age group and by presence or absence of preceding COVID-19. Results: A total of 1733 patients with MIS-C were identified; 994 (57.6%) were male and 1117 (71.3%) were Hispanic or non-Hispanic Black. Gastrointestinal symptoms, rash, and conjunctival hyperemia were reported by 53% (n = 931) to 67% (n = 1153) of patients. A total of 937 patients (54%) had hypotension or shock, and 1009 (58.2%) were admitted for intensive care. Cardiac dysfunction was reported in 484 patients (31.0%), pericardial effusion in 365 (23.4%), myocarditis in 300 (17.3%), and coronary artery dilatation or aneurysms in 258 (16.5%). Patients aged 0 to 4 years had the lowest proportion of severe manifestations, although 171 patients (38.4%) had hypotension or shock and 197 (44.3%) were admitted for intensive care. Patients aged 18 to 20 years had the highest proportions with myocarditis (17 [30.9%]), pneumonia (20 [36.4%]), acute respiratory distress syndrome (10 [18.2%]), and polymerase chain reaction positivity (39 [70.9%]). These older adolescents also had the highest proportion reporting preceding COVID-19-like illness (63%). Nationally, the first 2 MIS-C peaks followed the COVID-19 peaks by 2 to 5 weeks. The cumulative MIS-C incidence per 100 000 persons younger than 21 years was 2.1 and varied from 0.2 to 6.3 by state. Twenty-four patients (1.4%) died. Conclusions and Relevance: In this cross-sectional study of a large cohort of patients with MIS-C, 2 peaks that followed COVID-19 peaks by 2 to 5 weeks were identified. The geographic and temporal association of MIS-C with the COVID-19 pandemic suggested that MIS-C resulted from delayed immunologic responses to SARS-CoV-2 infection. The clinical manifestations varied by age and by presence or absence of preceding COVID-19.

Factors linked to severe outcomes in multisystem inflammatory syndrome in children (MIS-C) in the USA: a retrospective surveillance study.

BACKGROUND: Multisystem inflammatory syndrome in children (MIS-C) is a newly identified and serious health condition associated with SARS-CoV-2 infection. Clinical manifestations vary widely among patients with MIS-C, and the aim of this study was to investigate factors associated with severe outcomes. METHODS: In this retrospective surveillance study, patients who met the US Centers for Disease Control and Prevention (CDC) case definition for MIS-C (younger than 21 years, fever, laboratory evidence of inflammation, admitted to hospital, multisystem [≥2] organ involvement [cardiac, renal, respiratory, haematological, gastrointestinal, dermatological, or neurological], no alternative plausible diagnosis, and either laboratory confirmation of SARS-CoV-2 infection by RT-PCR, serology, or antigen test, or known COVID-19 exposure within 4 weeks before symptom onset) were reported from state and local health departments to the CDC using standard case-report forms. Factors assessed for potential links to severe outcomes included pre-existing patient factors (sex, age, race or ethnicity, obesity, and MIS-C symptom onset date before June 1, 2020) and clinical findings (signs or symptoms and laboratory markers). Logistic regression models, adjusted for all pre-existing factors, were used to estimate odds ratios between potential explanatory factors and the following outcomes: intensive care unit (ICU) admission, shock, decreased cardiac function, myocarditis, and coronary artery abnormalities. FINDINGS: 1080 patients met the CDC case definition for MIS-C and had symptom onset between March 11 and Oct 10, 2020. ICU admission was more likely in patients aged 6-12 years (adjusted odds ratio 1·9 [95% CI 1·4-2·6) and patients aged 13-20 years (2·6 [1·8-3·8]), compared with patients aged 0-5 years, and more likely in non-Hispanic Black patients, compared with non-Hispanic White patients (1·6 [1·0-2·4]). ICU admission was more likely for patients with shortness of breath (1·9 [1·2-2·9]), abdominal pain (1·7 [1·2-2·7]), and patients with increased concentrations of C-reactive protein, troponin, ferritin, D-dimer, brain natriuretic peptide (BNP), N-terminal pro B-type BNP, or interleukin-6, or reduced platelet or lymphocyte counts. We found similar associations for decreased cardiac function, shock, and myocarditis. Coronary artery abnormalities were more common in male patients (1·5 [1·1-2·1]) than in female patients and patients with mucocutaneous lesions (2·2 [1·3-3·5]) or conjunctival injection (2·3 [1·4-3·7]). INTERPRETATION: Identification of important demographic and clinical characteristics could aid in early recognition and prompt management of severe outcomes for patients with MIS-C. FUNDING: None.

Multisystem Inflammatory Syndrome in Children Associated with Severe Acute Respiratory Syndrome Coronavirus 2: A Systematic Review.

OBJECTIVE: To develop a more comprehensive description of multisystem inflammatory syndrome in children (MIS-C), a novel syndrome linked to severe acute respiratory syndrome coronavirus 2, by conducting a systematic analysis of studies from different settings that used various inclusion criteria. STUDY DESIGN: MIS-C studies were identified by searching PubMed and Embase as well as preprint repositories and article references to identify studies of MIS-C cases published from April 25, 2020, through June 29, 2020. MIS-C study metadata were assessed and information on case demographics, clinical symptoms, laboratory measurements, treatments, and outcomes were summarized and contrasted between studies. RESULTS: Eight studies were identified representing a total of 440 MIS-C cases. Inclusion criteria varied by study: 3 studies selected patients diagnosed with Kawasaki disease, 2 required cardiovascular involvement, and 3 had broader multisystem inclusion criteria. Median age of patients by study ranged from 7.3 to 10 years, and 59% of patients were male. Across all studies, the proportion of patients with positive results for severe acute respiratory syndrome coronavirus 2 reverse transcriptase-polymerase chain reaction tests ranged from 13% to 69% and for serology, from 75% to 100%. Patients with MIS-C had high prevalence of gastrointestinal (87%), dermatologic/mucocutaneous (73%), and cardiovascular (71%) symptoms. Prevalence of cardiovascular, neurologic, and respiratory system involvement significantly differed by study inclusion criteria. All studies reported elevated C-reactive protein, interleukin-6, and fibrinogen levels for at least 75% of patients in each study. CONCLUSIONS: This systematic review of MIS-C studies assists with understanding this newly identified syndrome and may be useful in developing a refined, universal case definition of MIS-C.

COVID-19-Associated Multisystem Inflammatory Syndrome in Children - United States, March-July 2020.

In April 2020, during the peak of the coronavirus disease 2019 (COVID-19) pandemic in Europe, a cluster of children with hyperinflammatory shock with features similar to Kawasaki disease and toxic shock syndrome was reported in England* (1). The patients' signs and symptoms were temporally associated with COVID-19 but presumed to have developed 2-4 weeks after acute COVID-19; all children had serologic evidence of infection with SARS-CoV-2, the virus that causes COVID-19 (1). The clinical signs and symptoms present in this first cluster included fever, rash, conjunctivitis, peripheral edema, gastrointestinal symptoms, shock, and elevated markers of inflammation and cardiac damage (1). On May 14, 2020, CDC published an online Health Advisory that summarized the manifestations of reported multisystem inflammatory syndrome in children (MIS-C), outlined a case definition,† and asked clinicians to report suspected U.S. cases to local and state health departments. As of July 29, a total of 570 U.S. MIS-C patients who met the case definition had been reported to CDC. A total of 203 (35.6%) of the patients had a clinical course consistent with previously published MIS-C reports, characterized predominantly by shock, cardiac dysfunction, abdominal pain, and markedly elevated inflammatory markers, and almost all had positive SARS-CoV-2 test results. The remaining 367 (64.4%) of MIS-C patients had manifestations that appeared to overlap with acute COVID-19 (2-4), had a less severe clinical course, or had features of Kawasaki disease.§ Median duration of hospitalization was 6 days; 364 patients (63.9%) required care in an intensive care unit (ICU), and 10 patients (1.8%) died. As the COVID-19 pandemic continues to expand in many jurisdictions, clinicians should be aware of the signs and symptoms of MIS-C and report suspected cases to their state or local health departments; analysis of reported cases can enhance understanding of MIS-C and improve characterization of the illness for early detection and treatment.