Introduction
Antibiotic use may shorten mechanical ventilation duration and length of stay for patients with bronchiolitis that require intubation. The goals of this study were to describe antibiotic ...use in previously healthy children with bronchiolitis admitted to the intensive care unit (ICU) for noninvasive respiratory support and to describe associations of early antibiotic use with clinical outcomes.
Methods
The Pediatric Health Information Systems database was queried for children <2 years of age without significant comorbidities admitted to the ICU for bronchiolitis. Children requiring mechanical ventilation on the first ICU day were excluded. Two groups were analyzed: those patients receiving antibiotics on the first day of their ICU stay (early antibiotics), and those receiving no antibiotics on their first ICU day (no antibiotics). Primary outcome was the length of ICU stay.
Results
A total of 11,029 admissions met criteria, 2522 (22.9%) in the early antibiotic group, and 8507 (77.1%) in the no antibiotic group. The use of early antibiotics varied by center from 10% to 54%. In multivariate analysis, the early antibiotic group had similar ICU length of stay compared to the no antibiotic group (relative risk, RR 95% confidence interval, CI 1.01 0.98–1.05). For patients on noninvasive ventilation, the first ICU day early antibiotics did not impact ICU length of stay (RR 95% CI 0.97 0.92–1.02) or need for intubation (RR 95% CI 1.11 0.77–1.58).
Conclusion
Early antibiotic use was common with significant variation between centers. Early antibiotic use was not associated with improved clinical outcomes in children admitted to the ICU for noninvasive respiratory support for bronchiolitis.
Experimental autoimmune encephalomyelitis (EAE) is a Th1 and Th17 cell-mediated autoimmune disease of the CNS. IDO and tryptophan metabolites have inhibitory effects on Th1 cells in EAE. For Th17 ...cells, IDO-mediated tryptophan deprivation and small molecule halofuginone-induced amino acid starvation response were shown to activate general control nonrepressed 2 (GCN2) kinase that directly or indirectly inhibits Th17 cell differentiation. However, it remains unclear whether IDO and tryptophan metabolites impact the Th17 cell response by mechanisms other than the GCN2 kinase pathway. In this article, we show that IDO-deficient mice develop exacerbated EAE with enhanced encephalitogenic Th1 and Th17 cell responses and reduced regulatory T cell (Treg) responses. Administration of the downstream tryptophan metabolite 3-hydroxyanthranillic acid (3-HAA) enhanced the percentage of Tregs, inhibited Th1 and Th17 cells, and ameliorated EAE. We further demonstrate that Th17 cells are less sensitive to direct suppression by 3-HAA than are Th1 cells. 3-HAA treatment in vitro reduced IL-6 production by activated spleen cells and increased expression of TGF-β in dendritic cells (DCs), which correlated with enhanced levels of Tregs, suggesting that 3-HAA-induced Tregs contribute to inhibition of Th17 cells. By using a DC-T cell coculture, we found that 3-HAA-treated DCs expressed higher levels of TGF-β and had properties to induce generation of Tregs from anti-CD3/anti-CD28-stimulated naive CD4(+) T cells. Thus, our data support the hypothesis that IDO induces the generation of Tregs via tryptophan metabolites, such as 3-HAA, which enhances TGF-β expression from DCs and promotes Treg differentiation.
Detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigens in blood has high sensitivity in adults with acute coronavirus disease 2019 (COVID-19), but sensitivity in pediatric ...patients is unclear. Recent data suggest that persistent SARS-CoV-2 spike antigenemia may contribute to multisystem inflammatory syndrome in children (MIS-C). We quantified SARS-CoV-2 nucleocapsid (N) and spike (S) antigens in blood of pediatric patients with either acute COVID-19 or MIS-C using ultrasensitive immunoassays (Meso Scale Discovery).
Plasma was collected from inpatients (<21 years) enrolled across 15 hospitals in 15 US states. Acute COVID-19 patients (n = 36) had a range of disease severity and positive nasopharyngeal SARS-CoV-2 RT-PCR within 24 hours of blood collection. Patients with MIS-C (n = 53) met CDC criteria and tested positive for SARS-CoV-2 (RT-PCR or serology). Controls were patients pre-COVID-19 (n = 67) or within 24 hours of negative RT-PCR (n = 43).
Specificities of N and S assays were 95-97% and 100%, respectively. In acute COVID-19 patients, N/S plasma assays had 89%/64% sensitivity; sensitivities in patients with concurrent nasopharyngeal swab cycle threshold (Ct) ≤35 were 93%/63%. Antigen concentrations ranged from 1.28-3844 pg/mL (N) and 1.65-1071 pg/mL (S) and correlated with disease severity. In MIS-C, antigens were detected in 3/53 (5.7%) samples (3 N-positive: 1.7, 1.9, 121.1 pg/mL; 1 S-positive: 2.3 pg/mL); the patient with highest N had positive nasopharyngeal RT-PCR (Ct 22.3) concurrent with blood draw.
Ultrasensitive blood SARS-CoV-2 antigen measurement has high diagnostic yield in children with acute COVID-19. Antigens were undetectable in most MIS-C patients, suggesting that persistent antigenemia is not a common contributor to MIS-C pathogenesis.
Seasonal influenza virus infection causes a range of disease severity, including lower respiratory tract infection with respiratory failure. We evaluated the association of common variants in ...interferon (IFN) regulatory genes with susceptibility to critical influenza infection in children.
We performed targeted sequencing of 69 influenza-associated candidate genes in 348 children from 24 US centers admitted to the intensive care unit with influenza infection and lacking risk factors for severe influenza infection (PICFlu cohort, 59.4% male). As controls, whole genome sequencing from 675 children with asthma (CAMP cohort, 62.5% male) was compared. We assessed functional relevance using PICFlu whole blood gene expression levels for the gene and calculated IFN gene signature score.
Common variants in DDX58, encoding the retinoic acid-inducible gene I (RIG-I) receptor, demonstrated association above or around the Bonferroni-corrected threshold (synonymous variant rs3205166; intronic variant rs4487862). The intronic single-nucleotide polymorphism rs4487862 minor allele was associated with decreased DDX58 expression and IFN signature (P < .05 and P = .0009, respectively) which provided evidence supporting the genetic variants' impact on RIG-I and IFN immunity.
We provide evidence associating common gene variants in DDX58 with susceptibility to severe influenza infection in children. RIG-I may be essential for preventing life-threatening influenza-associated disease.
The American Academy of Pediatrics (AAP) recommends supportive care for the management of bronchiolitis. However, patients admitted to the intensive care unit with severe (critical) bronchiolitis ...define a unique group with varying needs for both non-invasive and invasive respiratory support. Currently, no guidance exists to help clinicians discern who will progress to invasive mechanical support. Here, we sought to identify key clinical features that distinguish pediatric patients with critical bronchiolitis requiring invasive mechanical ventilation from those that did not. We conducted a retrospective cohort study at a tertiary pediatric medical center. Children ≤2 years old admitted to the pediatric intensive care unit (PICU) from January 2015 to December 2019 with acute bronchiolitis were studied. Patients were divided into non-invasive respiratory support (NRS) and invasive mechanical ventilation (IMV) groups; the IMV group was further subdivided depending on timing of intubation relative to PICU admission. Of the 573 qualifying patients, 133 (23%) required invasive mechanical ventilation. Median age and weight were lower in the IMV group, while incidence of prematurity and pre-existing neurologic or genetic conditions were higher compared to the NRS group. Multi-microbial pneumonias were diagnosed more commonly in the IMV group, in turn associated with higher severity of illness scores, longer PICU lengths of stay, and more antibiotic usage. Within the IMV group, those intubated earlier had a shorter duration of mechanical ventilation and PICU length of stay, associated with lower pathogen load and, in turn, shorter antibiotic duration. Taken together, our data reveal that critically ill patients with bronchiolitis who require mechanical ventilation possess high risk features, including younger age, history of prematurity, neurologic or genetic co-morbidities, and a propensity for multi-microbial infections.
Investigators used a case–control, test-negative design to assess the effectiveness of the BNT162b2 vaccine in adolescents for the prevention of Covid-19–related hospitalization, ICU admission, or ...receipt of life support. Among 445 case patients and 777 controls, of the 180 patients admitted to an ICU, only 2 had been fully vaccinated; all 7 deaths occurred in unvaccinated patients.
Background Cardiac complications related to COVID‐19 in children and adolescents include ventricular dysfunction, myocarditis, coronary artery aneurysm, and bradyarrhythmias, but tachyarrhythmias are ...less understood. The goal of this study was to evaluate the frequency, characteristics, and outcomes of children and adolescents experiencing tachyarrhythmias while hospitalized for acute severe COVID‐19 or multisystem inflammatory syndrome in children. Methods and Results This study involved a case series of 63 patients with tachyarrhythmias reported in a public health surveillance registry of patients aged <21 years hospitalized from March 15, 2020, to December 31, 2021, at 63 US hospitals. Patients with tachyarrhythmias were compared with patients with severe COVID‐19–related complications without tachyarrhythmias. Tachyarrhythmias were reported in 22 of 1257 patients (1.8%) with acute COVID‐19 and 41 of 2343 (1.7%) patients with multisystem inflammatory syndrome in children. They included supraventricular tachycardia in 28 (44%), accelerated junctional rhythm in 9 (14%), and ventricular tachycardia in 38 (60%); >1 type was reported in 12 (19%). Registry patients with versus without tachyarrhythmia were older (median age, 15.4 range, 10.4–17.4 versus 10.0 range, 5.4–14.8 years) and had higher illness severity on hospital admission. Intervention for treatment of tachyarrhythmia was required in 37 (59%) patients and included antiarrhythmic medication (n=31, 49%), electrical cardioversion (n=11, 17%), cardiopulmonary resuscitation (n=8, 13%), and extracorporeal membrane oxygenation (n=9, 14%). Patients with tachyarrhythmias had longer hospital length of stay than those who did not, and 9 (14%) versus 77 (2%) died. Conclusions Tachyarrhythmias were a rare complication of acute severe COVID‐19 and multisystem inflammatory syndrome in children and adolescents and were associated with worse clinical outcomes, highlighting the importance of close monitoring, aggressive treatment, and postdischarge care.
In this study, maternal vaccination with an mRNA vaccine during pregnancy was less common among infants hospitalized for Covid-19 than among controls. The effectiveness of maternal vaccination ...against Covid-19 hospitalization of infants was 52% overall and was greater when delta, rather than omicron, was predominant.
Abstract Intravenous (i.v.) administration of autoantigen effectively induces Ag-specific tolerance against experimental autoimmune encephalomyelitis (EAE). We and others have shown enhanced EAE ...severity in mice lacking IL-12 or its receptor, strongly suggesting an immunoregulatory effect of IL-12 signaling. To examine the role of IL-12 responsiveness in autoantigen-induced tolerance in EAE, we administered autoantigen i.v. in two distinct treatment regimes to wildtype and IL-12Rβ2−/− mice, immunized to develop EAE. Administration at the induction phase suppressed EAE in wildtype and IL-12Rβ2−/− mice however the effect was somewhat less potent in the absence of IL-12Rβ2. Expression of pro-inflammatory cytokines such as IFN-γ, IL-17 and IL-2, was inhibited in wild-type tolerized mice but less so in IL-12Rβ2−/− mice. I.v. antigen was also effective in suppressing disease in both genotypes when given during the clinical phase of disease with similar CNS inflammation, demyelination and peripheral inflammatory cytokine profiles observed in both genotypes. There was however a mild impact of a lack of IL-12 signaling on Treg induction during tolerance induction compared to WT mice in this treatment regime. These findings show that the enhanced severity of EAE that occurs in the absence of IL-12 signaling can be effectively overcome by i.v. autoantigen, indicating that this therapeutic effect is not primarily mediated by IL-12 and that i.v. tolerance could be a powerful approach in suppressing severe and aggressive MS.
Abstract
Background
Predominance of 2 antigenically drifted influenza viruses during the 2019–2020 season offered an opportunity to assess vaccine effectiveness against life-threatening pediatric ...influenza disease from vaccine-mismatched viruses in the United States.
Methods
We enrolled children aged <18 years admitted to the intensive care unit with acute respiratory infection across 17 hospitals. Respiratory specimens were tested using reverse-transcription polymerase chain reaction for influenza viruses and sequenced. Using a test-negative design, we estimated vaccine effectiveness comparing odds of vaccination in test-positive case patients vs test-negative controls, stratifying by age, virus type, and severity. Life-threating influenza included death or invasive mechanical ventilation, vasopressors, cardiopulmonary resuscitation, dialysis, or extracorporeal membrane oxygenation.
Results
We enrolled 159 critically ill influenza case-patients (70% ≤8 years; 51% A/H1N1pdm09 and 25% B-Victoria viruses) and 132 controls (69% were aged ≤8 years). Among 56 sequenced A/H1N1pdm09 viruses, 29 (52%) were vaccine-mismatched (A/H1N1pdm09/5A+156K) and 23 (41%) were vaccine-matched (A/H1N1pdm09/5A+187A,189E). Among sequenced B-lineage viruses, majority (30 of 31) were vaccine-mismatched. Effectiveness against critical influenza was 63% (95% confidence interval CI, 38% to 78%) and similar by age. Effectiveness was 75% (95% CI, 49% to 88%) against life-threatening influenza vs 57% (95% CI, 24% to 76%) against non-life-threating influenza. Effectiveness was 78% (95% CI, 41% to 92%) against matched A(H1N1)pdm09 viruses, 47% (95% CI, –21% to 77%) against mismatched A(H1N1)pdm09 viruses, and 75% (95% CI, 37% to 90%) against mismatched B-Victoria viruses.
Conclusions
During a season when vaccine-mismatched influenza viruses predominated, vaccination was associated with a reduced risk of critical and life-threatening influenza illness in children.
In the largest study of its kind, vaccination averted most critical (63%) and life-threatening (75%) influenza among children aged <18 years. This reduction was impressive because vaccine components were mismatched to the 2 predominant circulating influenza strains during this season.
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