Characteristics and Outcomes of Critically Ill Children With Multisystem Inflammatory Syndrome.

OBJECTIVES: To characterize the prevalence of pediatric critical illness from multisystem inflammatory syndrome in children (MIS-C) and to assess the influence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) strain on outcomes. DESIGN: Retrospective cohort study. SETTING: Database evaluation using the Virtual Pediatric Systems Database. PATIENTS: All children with MIS-C admitted to the PICU in 115 contributing hospitals between January 1, 2020, and June 30, 2021. MEASUREMENTS AND MAIN RESULTS: Of the 145,580 children admitted to the PICU during the study period, 1,338 children (0.9%) were admitted with MIS-C with the largest numbers of children admitted in quarter 1 (Q1) of 2021 ( n = 626). The original SARS-CoV-2 viral strain and the D614G Strain were the predominant strains through 2020, with Alpha B.1.1.7 predominating in Q1 and quarter 2 (Q2) of 2021. Overall, the median PICU length of stay (LOS) was 2.7 days (25-75% interquartile range [IQR], 1.6-4.7 d) with a median hospital LOS of 6.6 days (25-75% IQR, 4.7-9.3 d); 15.2% received mechanical ventilation with a median duration of mechanical ventilation of 3.1 days (25-75% IQR, 1.9-5.8 d), and there were 11 hospital deaths. During the study period, there was a significant decrease in the median PICU and hospital LOS and a decrease in the frequency of mechanical ventilation, with the most significant decrease occurring between quarter 3 and quarter 4 (Q4) of 2020. Children admitted to a PICU from the general care floor or from another ICU/step-down unit had longer PICU LOS than those admitted directly from an emergency department. CONCLUSIONS: Overall mortality from MIS-C was low, but the disease burden was high. There was a peak in MIS-C cases during Q1 of 2021, following a shift in viral strains in Q1 of 2021. However, an improvement in MIS-C outcomes starting in Q4 of 2020 suggests that viral strain was not the driving factor for outcomes in this population.

School Closures in the United States and Severe Respiratory Illnesses in Children: A Normalized Nationwide Sample.

OBJECTIVES: To determine the association between nationwide school closures and prevalence of common admission diagnoses in the pediatric critical care unit. DESIGN: Retrospective cohort study. SETTING: National database evaluation using the Virtual Pediatric Systems LLC database. PATIENTS: All patients admitted to the PICU in 81 contributing hospitals in the United States. MEASUREMENTS AND MAIN RESULTS: Diagnosis categories were determined for all 110,418 patients admitted during the 20-week study period in each year (2018, 2019, and 2020). Admission data were normalized relative to statewide school closure dates for each patient using geographic data. The "before school closure" epoch was defined as 8 weeks prior to school closure, and the "after school closure" epoch was defined as 12 weeks following school closure. For each diagnosis, admission ratios for each study day were calculated by dividing 2020 admissions by 2018-2019 admissions. The 10 most common diagnosis categories were examined. Significant changes in admission ratios were identified for bronchiolitis, pneumonia, and asthma. These changes occurred at 2, 8, and 35 days following school closure, respectively. PICU admissions decreased by 82% for bronchiolitis, 76% for pneumonia, and 76% for asthma. Nonrespiratory diseases such as diabetic ketoacidosis, status epilepticus, traumatic injury, and poisoning/ingestion did not show significant changes following school closure. CONCLUSIONS: School closures are associated with a dramatic reduction in the prevalence of severe respiratory disease requiring PICU admission. School closure may be an effective tool to mitigate future pandemics but should be balanced with potential academic, economic, mental health, and social consequences.