Factors Associated With Severe Illness in Patients Aged <21 Years Hospitalized for COVID-19.

OBJECTIVES: To describe coronavirus disease 2019 (COVID-19)-related pediatric hospitalizations during a period of B.1.617.2 (Δ) variant predominance and to determine age-specific factors associated with severe illness. METHODS: We abstracted data from medical charts to conduct a cross-sectional study of patients aged <21 years hospitalized at 6 United States children's hospitals from July to August 2021 for COVID-19 or with an incidental positive severe acute respiratory syndrome coronavirus 2 test. Among patients with COVID-19, we assessed factors associated with severe illness by calculating age-stratified prevalence ratios (PR). We defined severe illness as receiving high-flow nasal cannula, positive airway pressure, or invasive mechanical ventilation. RESULTS: Of 947 hospitalized patients, 759 (80.1%) had COVID-19, of whom 287 (37.8%) had severe illness. Factors associated with severe illness included coinfection with respiratory syncytial virus (RSV) (PR 3.64) and bacteria (PR 1.88) in infants; RSV coinfection in patients aged 1 to 4 years (PR 1.96); and obesity in patients aged 5 to 11 (PR 2.20) and 12 to 17 years (PR 2.48). Having ≥2 underlying medical conditions was associated with severe illness in patients aged <1 (PR 1.82), 5 to 11 (PR 3.72), and 12 to 17 years (PR 3.19). CONCLUSIONS: Among patients hospitalized for COVID-19, factors associated with severe illness included RSV coinfection in those aged <5 years, obesity in those aged 5 to 17 years, and other underlying conditions for all age groups <18 years. These findings can inform pediatric practice, risk communication, and prevention strategies, including vaccination against COVID-19.

Characteristics and Clinical Outcomes of Children and Adolescents Aged <18 Years Hospitalized with COVID-19 - Six Hospitals, United States, July-August 2021.

During June 2021, the highly transmissible† B.1.617.2 (Delta) variant of SARS-CoV-2, the virus that causes COVID-19, became the predominant circulating strain in the United States. U.S. pediatric COVID-19-related hospitalizations increased during July-August 2021 following emergence of the Delta variant and peaked in September 2021.§ As of May 12, 2021, CDC recommended COVID-19 vaccinations for persons aged ≥12 years,¶ and on November 2, 2021, COVID-19 vaccinations were recommended for persons aged 5-11 years.** To date, clinical signs and symptoms, illness course, and factors contributing to hospitalizations during the period of Delta predominance have not been well described in pediatric patients. CDC partnered with six children's hospitals to review medical record data for patients aged <18 years with COVID-19-related hospitalizations during July-August 2021.†† Among 915 patients identified, 713 (77.9%) were hospitalized for COVID-19 (acute COVID-19 as the primary or contributing reason for hospitalization), 177 (19.3%) had incidental positive SARS-CoV-2 test results (asymptomatic or mild infection unrelated to the reason for hospitalization), and 25 (2.7%) had multisystem inflammatory syndrome in children (MIS-C), a rare but serious inflammatory condition associated with COVID-19.§§ Among the 713 patients hospitalized for COVID-19, 24.7% were aged <1 year, 17.1% were aged 1-4 years, 20.1% were aged 5-11 years, and 38.1% were aged 12-17 years. Approximately two thirds of patients (67.5%) had one or more underlying medical conditions, with obesity being the most common (32.4%); among patients aged 12-17 years, 61.4% had obesity. Among patients hospitalized for COVID-19, 15.8% had a viral coinfection¶¶ (66.4% of whom had respiratory syncytial virus [RSV] infection). Approximately one third (33.9%) of patients aged <5 years hospitalized for COVID-19 had a viral coinfection. Among 272 vaccine-eligible (aged 12-17 years) patients hospitalized for COVID-19, one (0.4%) was fully vaccinated.*** Approximately one half (54.0%) of patients hospitalized for COVID-19 received oxygen support, 29.5% were admitted to the intensive care unit (ICU), and 1.5% died; of those requiring respiratory support, 14.5% required invasive mechanical ventilation (IMV). Among pediatric patients with COVID-19-related hospitalizations, many had severe illness and viral coinfections, and few vaccine-eligible patients hospitalized for COVID-19 were vaccinated, highlighting the importance of vaccination for those aged ≥5 years and other prevention strategies to protect children and adolescents from COVID-19, particularly those with underlying medical conditions.

A bioinspired and chemically defined alternative to dimethyl sulfoxide for the cryopreservation of human hematopoietic stem cells.

The cryopreservation of hematopoietic cells using dimethyl sulfoxide (DMSO) and serum is a common procedure used in transplantation. However, DMSO has clinical and biological side effects due to its toxicity, and serum introduces variation and safety risks. Inspired by natural antifreeze proteins, a novel class of ice-interactive cryoprotectants was developed. The corresponding DMSO-, protein-, and serum-free cryopreservation media candidates were screened through a series of biological assays using human cell lines, peripheral blood cells, and bone marrow cells. XT-Thrive-A and XT-Thrive-B were identified as lead candidates to rival cryopreservation with 10% DMSO in serum based on post-thaw cell survival and short-term proliferation assays. The effectiveness of the novel cryopreservation media in freezing hematopoietic stem cells from human whole bone marrow was assessed by extreme limiting dilution analysis in immunodeficient mice. Stem cell frequencies were measured 12 weeks after transplant based on bone marrow engraftment of erythroid, myeloid, B-lymphoid, and CD34+ progenitors measured by flow cytometry. The recovered numbers of cryopreserved stem cells were similar among XT-Thrive A, XT-Thrive B, and DMSO with serum groups. These findings show that cryoprotectants developed through biomimicry of natural antifreeze proteins offers a substitute for DMSO-based media for the cryopreservation of hematopoietic stem cells.

Discovery of Stable and Selective Antibody Mimetics from Combinatorial Libraries of Polyvalent, Loop-Functionalized Peptoid Nanosheets.

The ability of antibodies to bind a wide variety of analytes with high specificity and high affinity makes them ideal candidates for therapeutic and diagnostic applications. However, the poor stability and high production cost of antibodies have prompted exploration of a variety of synthetic materials capable of specific molecular recognition. Unfortunately, it remains a fundamental challenge to create a chemically diverse population of protein-like, folded synthetic nanostructures with defined molecular conformations in water. Here we report the synthesis and screening of combinatorial libraries of sequence-defined peptoid polymers engineered to fold into ordered, supramolecular nanosheets displaying a high spatial density of diverse, conformationally constrained peptoid loops on their surface. These polyvalent, loop-functionalized nanosheets were screened using a homogeneous Förster resonance energy transfer (FRET) assay for binding to a variety of protein targets. Peptoid sequences were identified that bound to the heptameric protein, anthrax protective antigen, with high avidity and selectivity. These nanosheets were shown to be resistant to proteolytic degradation, and the binding was shown to be dependent on the loop display density. This work demonstrates that key aspects of antibody structure and function-the creation of multivalent, combinatorial chemical diversity within a well-defined folded structure-can be realized with completely synthetic materials. This approach enables the rapid discovery of biomimetic affinity reagents that combine the durability of synthetic materials with the specificity of biomolecular materials.

Lipid-anchor display on peptoid nanosheets via co-assembly for multivalent pathogen recognition.

Biological systems have evolved sophisticated molecular assemblies capable of exquisite molecular recognition across length scales ranging from angstroms to microns. For instance, the self-organization of glycolipids and glycoproteins on cell membranes allows for molecular recognition of a diversity of ligands ranging from small molecules and proteins to viruses and whole cells. A distinguishing feature of these 2D surfaces is they achieve exceptional binding selectivity and avidity by exploiting multivalent binding interactions. Here we develop a 2D ligand display platform based on peptoid nanosheets that mimics the structure and function of the cell membrane. A variety of small-molecule lipid-conjugates were co-assembled with the peptoid chains to create a diversity of functionalized nanosheet bilayers with varying display densities. The functional heads of the lipids were shown to be surface-exposed, and the carbon tails immobilized into the hydrophobic interior. We demonstrate that saccharide-functionalized nanosheets (e.g., made from globotriaosylsphingosine or 1,2-dipalmitoyl-sn-glycero-3-phospho((ethyl-1',2',3'-triazole)triethyleneglycolmannose)) can have very diverse binding properties, exhibiting specific binding to multivalent proteins as well as to intact bacterial cells. Analysis of sugar display densities revealed that Shiga toxin 1 subunit B (a pentameric protein) and FimH-expressing Escherichia coli (E. coli) bind through the cooperative binding behavior of multiple carbohydrates. The ability to readily incorporate and display a wide variety of lipidated cargo on the surface of peptoid nanosheets makes this a convenient route to soluble, cell-surface mimetic materials. These materials hold great promise for drug screening, biosensing, bioremediation, and as a means to combat pathogens by direct physical binding through a well-defined, multivalent 2D material.

Electrostatic Assemblies of Single-Walled Carbon Nanotubes and Sequence-Tunable Peptoid Polymers Detect a Lectin Protein and Its Target Sugars.

A primary limitation to real-time imaging of metabolites and proteins has been the selective detection of biomolecules that have no naturally occurring or stable molecular recognition counterparts. We present developments in the design of synthetic near-infrared fluorescent nanosensors based on the fluorescence modulation of single-walled carbon nanotubes (SWNTs) with select sequences of surface-adsorbed N-substituted glycine peptoid polymers. We assess the stability of the peptoid-SWNT nanosensor candidates under variable ionic strengths, protease exposure, and cell culture media conditions and find that the stability of peptoid-SWNTs depends on the composition and length of the peptoid polymer. From our library, we identify a peptoid-SWNT assembly that can detect lectin protein wheat germ agglutinin (WGA) with a sensitivity comparable to the concentration of serum proteins. To demonstrate the retention of nanosensor-bound protein activity, we show that WGA on the nanosensor produces an additional fluorescent signal modulation upon exposure to the lectin's target sugars, suggesting the lectin protein remains active and selectively binds its target sugars through ternary molecular recognition interactions relayed to the nanosensor. Our results inform design considerations for developing synthetic molecular recognition elements by assembling peptoid polymers on SWNTs and also demonstrate these assemblies can serve as optical nanosensors for lectin proteins and their target sugars. Together, these data suggest certain peptoid sequences can be assembled with SWNTs to serve as versatile optical probes to detect proteins and their molecular substrates.

Lost to follow-up: failure to engage children in care in the first three months of diagnosis.

Loss to follow-up (LTFU) is a critical factor in determining clinical outcomes in HIV treatment programs. Identifying modifiable factors of LTFU is fundamental for designing effective patient-retention interventions. We analyzed factors contributing to children LTFU from a treatment program to identify those that can be modified. A case-control study involving 313 children was used to compare the sociodemographic and clinical characteristics of children LTFU (cases) with those remaining in care (controls) at a large pediatric HIV care setting in Botswana. We traced children through caregiver contacts and those we found, we conducted structured interviews with patients' caregivers. Children <5 years were nearly twice as likely as older children to be LTFU (57·8% versus 30·9%, p <0 .01). Approximately half (47·6%, n = 51) of LTFU patients failed to further engage in care after just one clinic visit, as compared to less than 1% (n = 2) in the control group (p < 0.01). Children LTFU were more likely than controls to have advanced disease, greater immunosuppression, and not to be receiving antiretroviral therapy. Among interviewed patient caregivers, psychosocial factors (e.g., stigma, religious beliefs, child rebellion, disclosure of HIV status) were characteristics of patients LTFU, but not of controls. Socioeconomic factors (e.g., lack of transportation, school-related activities, forgetting appointments) were cited predominantly by the controls. Pediatric patients and their caregivers need to be targeted and engaged at their initial clinic visit, with special attention to children <5 years. Possible interventions include providing psychosocial support for issues that deter patients from engaging with The Clinic. Collaboration with community-based organizations focused on reducing stigma may be useful in addressing these complex issues.

Persistent Organic Nanopores Amenable to Structural and Functional Tuning.

Rigid macrocycles 2, which share a hybrid backbone and the same set of side chains while having inner cavities with different inward-pointing functional groups, undergo similar nanotubular assembly as indicated by multiple techniques including (1)H NMR, fluorescence spectroscopy, and atomic force microscopy. The formation of tubular assemblies containing subnanometer pores is also attested by the different transmembrane ion-transport behavior observed for these macrocycles. Vesicle-based stopped-flow kinetic assay and single-channel electrophysiology with planar lipid bilayers show that the presence of an inward-pointing functional (X) group in the inner cavity of a macrocyclic building block exerts a major influence on the transmembrane ion-transporting preference of the corresponding self-assembling pore. Self-assembling pores with inward-pointing amino and methyl groups possess the surprising and remarkable capability of rejecting protons but are conducive to transporting larger ions. The inward-pointing groups also resulted in transmembrane pores with a different extent of positive electrostatic potentials, leading to channels having different preferences for transporting chloride ion. Results from this work demonstrate that synthetic modification at the molecular level can profoundly impact the property of otherwise structurally persistent supramolecular assemblies, with both expected tunability and suprisingly unusual behavior.

Extremely strong tubular stacking of aromatic oligoamide macrocycles.

As the third-generation rigid macrocycles evolved from progenitor 1, cyclic aromatic oligoamides 3, with a backbone of reduced constraint, exhibit extremely strong stacking with an astoundingly high affinity (estimated lower limit of Kdimer > 1013 M-1 in CHCl3), which leads to dispersed tubular stacks that undergo further assembly in solution. Computational study reveals a very large binding energy (-49.77 kcal mol-1) and indicates highly cooperative local dipole interactions that account for the observed strength and directionality for the stacking of 3. In the solid-state, X-ray diffraction (XRD) confirms that the aggregation of 3 results in well-aligned tubular stacks. The persistent tubular assemblies of 3, with their non-deformable sub-nm pore, are expected to possess many interesting functions. One such function, transmembrane ion transport, is observed for 3.

The Pediatric AIDS Corps: a 5-year evaluation.

BACKGROUND: The Baylor College of Medicine International Pediatric AIDS Initiative at Texas Children's Hospital created a global health corps named the Pediatric AIDS Corps (PAC) in June 2005. This report provides descriptive details and outputs for PAC over its first 5 years. METHODS: Demographic data were gathered about PAC physicians employed from July 2006 to June 2011. A 21-question survey was used to query PAC physicians about their experiences in the program. Data concerning clinical experiences and educational programs also were reviewed. RESULTS: A total of 128 physicians were employed with PAC. The median duration served was 22.7 months. Eighty-seven percent indicated that experience affected their future career choice, with half continuing to work with children and families living in resource-limited areas after they left PAC. Patient care was identified as the most rewarding part of their work (73%), whereas deaths (27%) were the most difficult. Baylor College of Medicine International Pediatric AIDS Initiative enrollment of HIV-infected children and adolescents into care and treatment increased from 6107 to 103 731 with the addition of PAC physicians. Approximately 500 local health care professionals per quarter benefited from HIV clinical attachments that were not available before PAC arrival. PAC physicians visited outreach sites providing in-depth HIV mentoring of local health care professionals, leading to 37% of the sites becoming self-sufficient. CONCLUSIONS: The positive evaluation by the PAC and the scale-up of clinical and educational programs support the recent calls for the development of a national global health corps program.

Aromatic oligoamide macrocycles with a backbone of reduced constraint.

Oligoamide macrocycles with a backbone partially constrained by hydrogen bonds have been prepared. These macrocycles, carrying multiple H-bonding side chains, underwent strong aggregation in solution and form long fibers in the solid state. In contrast to the strong and specific complexation of the guanidinium ion by analogous macrocycles with fully H-bond-constrained backbones, these macrocycles failed to recognize the same cation, indicating that reducing backbone constraint has led to a drastic change in their cavity.

Routine inpatient provider-initiated HIV testing in Malawi, compared with client-initiated community-based testing, identifies younger children at higher risk of early mortality.

OBJECTIVE: To determine how routine inpatient provider-initiated HIV testing differs from traditional community-based client-initiated testing with respect to clinical characteristics of children identified and outcomes of outpatient HIV care. DESIGN: Prospective observational cohort. METHODS: Routine clinical data were collected from children identified as HIV-infected by either testing modality in Lilongwe, Malawi, in 2008. After 1 year of outpatient HIV care at the Baylor College of Medicine Clinical Center of Excellence, outcomes were assessed. RESULTS: Of 742 newly identified HIV-infected children enrolling into outpatient HIV care, 20.9% were identified by routine inpatient HIV testing. Compared with community-identified children, hospital-identified patients were younger (median 25.0 vs 53.5 months), with more severe disease (22.2% vs 7.8% WHO stage IV). Of 466 children with known outcomes, 15.0% died within the first year of HIV care; median time to death was 15.0 weeks for community-identified children vs 6.0 weeks for hospital-identified children. The strongest predictors of early mortality were severe malnutrition (hazard ratio, 4.3; 95% confidence interval, 2.2-8.3), moderate malnutrition (hazard ratio, 3.2; confidence interval, 1.6-6.6), age < 12 months (hazard ratio, 3.2; 95% confidence interval, 1.4-7.2), age 12 to 24 months (hazard ratio, 2.5; 95% confidence interval, 1.1-5.7), and WHO stage IV (hazard ratio, 2.2; 95% confidence interval, 1.1-4.6). After controlling for other variables, hospital identification did not independently predict mortality. CONCLUSIONS: Routine inpatient HIV testing identifies a subset of younger HIV-infected children with more severe, rapidly progressing disease that traditional community-based testing modalities are currently missing.

Nine-year follow-up of HIV-infected Romanian children and adolescents receiving lopinavir/ritonavir-containing highly active antiretroviral therapy.

INTRODUCTION: Many Romanian children were infected nosocomially with human immunodeficiency virus (HIV) in the late 1980s. The Romanian-American Children's Center of Excellence in Constanta continues to follow approximately 450 of these patients. In 2001, 414 of these patients were initiated on triple therapy including lopinavir/ritonavir. Data from this cohort treated through August 2006 were published in April 2007 demonstrating that the treatment was well tolerated, with 337 children (81%) remaining on therapy after a median duration of >4 years. The current article describes the results of continued analysis of this cohort through end 2010. The objective of the study was to determine the long-term clinical outcomes of children and adolescents commenced on antiretroviral therapy (ART) including lopinavir/ritonavir. METHODS: Data were extracted retrospectively from the charts of the 336 patients remaining on lopinavir/ritonavir in August 2006. The following outcomes were analyzed: mortality, current patient status, viral load (VL), CD4 counts and reasons for discontinuation of lopinavir/ritonavir. RESULTS: The median age at initiation of lopinavir/ritonavir was 14.0 years (range 5.4 to 20.0 years). The median time on lopinavir/ritonavir treatment was 7.5 years (interquartile range 5.7 to 8.6 years). Overall mortality was 13.5%. Of the original 414 patients started on lopinavir/ritonavir in 2001, 199 (48.1%) remained on this therapy at the end of 2010 and of these 63.8% had undetectable viral load. CONCLUSION: Despite initial suboptimal ART, a significant proportion of patients subsequently treated with a lopinavir/ritonavir based regimen remained on this therapy for up to nine years.

Cavity-containing, backbone-rigidified foldamers and macrocycles.

This Feature Article gives an account for a host of readily available foldamers and macrocycles with well-defined shapes and non-deformable cavities that appeared over the last decade. Efforts to create porous molecular structures have led to the establishment of an effective strategy for enforcing the folding of unnatural aromatic oligoamide strands based on an especially robust three-center (bifurcated) hydrogen-bonding interaction. Based on such a strategy, aromatic oligoamides adopting crescent and helical conformations that contain non-collapsible cavities of tunable diameters have been created. Extending the same folding principle to the preparation of aromatic polyamides that would adopt pore-containing helical conformation instead led to the discovery of a highly efficient, one-pot macrocyclization process. Such a one-pot macrocyclization process has been successfully applied to the preparation of macrocycles with aromatic amide, hydrazide, urea and other backbones. Mechanistic study indicates that the high efficiencies observed for the formation of these macrocycles are due to the folding of the corresponding uncyclized oligomeric precursors of the corresponding macrocycles. Oligoamide macrocycles, along with their uncyclized, cavity-containing counterparts, i.e., crescent oligoamides, bind guests such as guanidinium (G) and octylguanidinium (OG) ions with tunable selectivity. Recent studies revealed that these rigid macrocycles tend to engage in extraordinarily strong, directional aggregation, leading to nanotubular assemblies containing pores of fixed sizes. Consistent with the presence of self-assembling nanopores, oligoamide macrocycles were found to assemble into transmembrane channels with high conductance.

Preparation and helical folding of aromatic polyamides.

Long aromatic polyamide chains are prepared from the corresponding monomers. The resultant polymer adopts a hollow helical conformation that is stabilized by intramolecular H-bonding interaction between side chains.

Mortality and clinical outcomes in HIV-infected children on antiretroviral therapy in Malawi, Lesotho, and Swaziland.

OBJECTIVE: To determine mortality and immune status improvement in HIV-infected pediatric patients on antiretroviral treatment (ART) in Malawi, Lesotho, and Swaziland. METHODS: We conducted a retrospective cohort study of patients aged <12 years at ART initiation at 3 sites in sub-Saharan Africa between 2004 and 2009. Twelve-month and overall mortality were estimated, and factors associated with mortality and immune status improvement were evaluated. RESULTS: Included in the study were 2306 patients with an average follow-up time on ART of 2.3 years (interquartile range 1.5-3.1 years). One hundred four patients (4.5%) died, 9.0% were lost to follow-up, and 1.3% discontinued ART. Of the 104 deaths, 77.9% occurred in the first year of treatment with a 12-month mortality rate of 3.5%. The overall mortality rate was 2.25 deaths/100 person-years (95% confidence interval [CI] 1.84-2.71). Increased 12-month mortality was associated with younger age; <6 months (hazard ratio [HR] = 8.11, CI 4.51-14.58), 6 to <12 months (HR = 3.43, CI 1.96-6.02), and 12 to <36 months (HR = 1.92, CI 1.16-3.19), and World Health Organization stage IV (HR = 4.35, CI 2.19-8.67). Immune status improvement at 12 months was less likely in patients with advanced disease and age <12 months. CONCLUSIONS: Despite challenges associated with pediatric ART in developing countries, low mortality and good treatment outcomes can be achieved. However, outcomes are worse in younger patients and those with advanced disease at the time of ART initiation, highlighting the importance of early diagnosis and treatment.