Structural and biochemical rationale for Beta variant protein booster vaccine broad cross-neutralization of SARS-CoV-2.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), responsible for the COVID-19 pandemic, uses a surface expressed trimeric spike glycoprotein for cell entry. This trimer is the primary target for neutralizing antibodies making it a key candidate for vaccine development. During the global pandemic circulating variants of concern (VOC) caused several waves of infection, severe disease, and death. The reduced efficacy of the ancestral trimer-based vaccines against emerging VOC led to the need for booster vaccines. Here we present a detailed characterization of the Sanofi Beta trimer, utilizing cryo-EM for structural elucidation. We investigate the conformational dynamics and stabilizing features using orthogonal SPR, SEC, nanoDSF, and HDX-MS techniques to better understand how this antigen elicits superior broad neutralizing antibodies as a variant booster vaccine. This structural analysis confirms the Beta trimer preference for canonical quaternary structure with two RBD in the up position and the reversible equilibrium between the canonical spike and open trimer conformations. Moreover, this report provides a better understanding of structural differences between spike antigens contributing to differential vaccine efficacy.

Rapid determination of influenza vaccine potency by an SPR-based method using subtype or lineage-specific monoclonal antibodies.

Potency testing and release of annual influenza vaccines require preparation, calibration, and distribution of reference antigens (RAs) and antisera every year, which takes an average of 8 to 12 weeks, and can be a major limiting factor in pandemic situations. Here we describe for the first time a robust Surface Plasmon Resonance (SPR)-based method that employs influenza subtype or lineage hemagglutinin (HA) specific monoclonal antibodies (mAbs) to measure the HA concentration in influenza multivalent vaccines. Implementing such an advanced test method will at the very least eliminate the rate-limiting and laborious efforts of making antisera reagents annually, and thus expedite the influenza vaccine delivery to the public by at least 6 weeks. Results demonstrate that the SPR-based method, developed using Biacore, is robust and not influenced by the type of RAs (inactivated whole virus, split, or subunit vaccine-derived materials), whether they are used as monovalent or multivalent preparations. HA concentrations obtained for monovalent drug substances (DS) or quadrivalent drug products (DP) of inactivated influenza split vaccine showed a tight correlation (the best fit value for the slope is 1.001 with R2 of 0.9815 and P-value <0.0001) with the corresponding values obtained by the current potency assay, Single Radial Immunodiffusion (SRID). Supplementary analysis of the results by the Bland-Altman plot demonstrated good agreement between the SPR and SRID methods, with no consistent bias of the SPR versus SRID method. We further demonstrate that the SPR-based method can be used to estimate HA concentrations in intermediates of the influenza vaccine manufacturing process containing varying matrices and impurity levels. Further, the results demonstrate that the method is sensitive to detecting degradation of HA caused by elevated temperature, low pH, and freezing. It is evident from this report and other published work that the advancement of analytical techniques and the early findings are encouraging for the implementation of alternate potency assays with far-reaching benefits covering both seasonal and pandemic influenza.

Assessing the stability-indicating properties of alternative potency assays for inactivated influenza vaccine.

Determination of the potency of a vaccine is critical to ensuring that an appropriate dose is delivered, lot-to-lot consistency is maintained, and that the formulation is stable over the life of the vaccine. The potency of inactivated influenza vaccines is determined routinely by the Single Radial Immunodiffusion (SRID) assay. A number of alternative potency assays have been proposed and have been under evaluation in recent years. The aim of this study was to compare a surface plasmon resonance-based assay and two different enzyme linked immunoassays against the current potency assay, SRID, and against mouse immunogenicity when haemagglutinin antigen of the A(H1N1)pdm09 component of an inactivated influenza vaccine is stressed by elevated temperature, low pH and freezing. This analysis demonstrated that the alternative assays had good correspondence with SRID for samples from most stress conditions and that the immunogenicity in mice corresponded with potency in SRID for all stress samples. Subject to further analysis, the assays have been shown to have the potential to possibly replace, and at least complement, SRID.

Safety of histamine-2 receptor blockers in hospitalized VLBW infants.

BACKGROUND: Histamine-2 receptor (H2) blockers are often used in very low birth weight infants despite lack of population specific efficacy and safety data. AIMS: We sought to describe safety and temporal trends in histamine-2 receptor (H2) blocker use in hospitalized very low birth weight (VLBW) infants. STUDY DESIGN: We conducted a retrospective cohort study using a clinical database populated by an electronic health record shared by 348 neonatal intensive care units in the United States. SUBJECTS: We included all VLBW infants without major congenital anomalies. OUTCOME MEASURES: We used multivariable logistic regression with generalizing estimating equations to evaluate the association between days of H2 blocker exposure and risk of: 1) death or necrotizing enterocolitis (NEC); 2) death or sepsis; and 3) death, NEC, or sepsis. RESULTS: Of 127,707 infants, 20,288 (16%) were exposed to H2 blockers for a total of 6,422,352days. Median gestational age for infants exposed to H2 blockers was 27weeks (25th 75th percentile 26, 29). H2 blocker use decreased from 18% of infants in 1997 to 8% in 2012 (p<0.001). On multivariable analysis, infants were at increased risk of the combined outcome of death, NEC, or sepsis on days exposed to H2 blockers (odds ratio=1.14) (95% confidence interval 1.08, 1.19). CONCLUSIONS: H2 blocker use is associated with increased risk of the combined outcome of death, NEC, or sepsis in hospitalized VLBW infants.

Electrographic status epilepticus and neurobehavioral outcomes in critically ill children.

PURPOSE: Electrographic seizures (ESs) and electrographic status epilepticus (ESE) are common in children with acute neurologic conditions in pediatric intensive care units (PICUs), and ESE is associated with worse functional and quality-of-life outcomes. As an exploratory study, we aimed to determine if ESE was associated with worse outcomes using more detailed neurobehavioral measures. METHODS: Three hundred children with an acute neurologic condition and altered mental status underwent clinically indicated EEG monitoring and were enrolled in a prospective observational study. We obtained follow-up data from subjects who were neurodevelopmentally normal prior to PICU admission. We evaluated for associations between ESE and adaptive behavior (Adaptive Behavior Assessment System-II, ABAS-II), behavioral and emotional problems (Child Behavior Checklist, CBCL), and executive function (Behavior Rating Inventory of Executive Function, BRIEF) using linear regression analyses. A p-value of <0.05 was considered significant. RESULTS: One hundred thirty-seven of 300 subjects were neurodevelopmentally normal prior to PICU admission. We obtained follow-up data from 36 subjects for the CBCL, 32 subjects for the ABAS-II, and 20 subjects for the BRIEF. The median duration from admission to follow-up was 2.6 years (IQR: 1.2-3.8). There were no differences in the acute care variables (age, sex, mental status category, intubation status, paralysis status, acute neurologic diagnosis category, seizure category, EEG background category, or short-term outcome) between subjects with and without follow-up data for any of the outcome measures. On univariate analysis, significant differences were not identified for CBCL total problem (ES coefficient: -4.1, p = 0.48; ESE coefficient: 8.9, p = 0.13) or BRIEF global executive function (ES coefficient: 2.1, p = 0.78; ESE coefficient: 14.1, p = 0.06) scores, although there were trends toward worse scores in subjects with ESE. On univariate analysis, ESs were not associated with worse scores (coefficient: -21.5, p = 0.051), while ESE (coefficient: -29.7, p = 0.013) was associated with worse ABAS-II adaptive behavioral global composite scores. On multivariate analysis, when compared to subjects with no seizures, both ESs (coefficient: -28, p=0.014) and ESE (coefficient: -36, p = 0.003) were associated with worse adaptive behavioral global composite scores. DISCUSSION: Among previously neurodevelopmentally normal children with acute neurologic disorders, ESs and ESE were associated with worse adaptive behavior and trends toward worse behavioral-emotional and executive function problems. This was a small exploratory study, and the impact of ESs and ESE on these neurobehavioral measures may be clarified by subsequent larger studies. This article is part of a Special Issue entitled "Status Epilepticus".

Electrographic status epilepticus and long-term outcome in critically ill children.

OBJECTIVE: Electrographic seizures (ES) and electrographic status epilepticus (ESE) are common in children in the pediatric intensive care unit (PICU) with acute neurologic conditions. We aimed to determine whether ES or ESE was associated with worse long-term outcomes. METHODS: Three hundred children with an acute neurologic condition and encephalopathy underwent clinically indicated EEG monitoring and were enrolled in a prospective observational study. We aimed to obtain follow-up data from 137 subjects who were neurodevelopmentally normal before PICU admission. RESULTS: Follow-up data were collected for 60 of 137 subjects (44%) at a median of 2.7 years. Subjects with and without follow-up data were similar in clinical characteristics during the PICU admission. Among subjects with follow-up data, ES occurred in 12 subjects (20%) and ESE occurred in 14 subjects (23%). Multivariable analysis indicated that ESE was associated with an increased risk of unfavorable Glasgow Outcome Scale (Extended Pediatric Version) category (odds ratio 6.36, p = 0.01) and lower Pediatric Quality of Life Inventory scores (23 points lower, p = 0.001). Among subjects without prior epilepsy diagnoses ESE was associated with an increased risk of subsequently diagnosed epilepsy (odds ratio 13.3, p = 0.002). ES were not associated with worse outcomes. CONCLUSIONS: Among children with acute neurologic disorders who were reported to be neurodevelopmentally normal before PICU admission, ESE but not ES was associated with an increased risk of unfavorable global outcome, lower health-related quality of life scores, and an increased risk of subsequently diagnosed epilepsy even after adjusting for neurologic disorder category, EEG background category, and age.

Characterization of the retention behavior of organic and pharmaceutical drug molecules on an immobilized artificial membrane column with the Abraham model.

Data have been compiled from the published literature on the retention factors of 174 organic compounds and drug molecules eluted from a Regis Technologies IAM.PC.DD2 HPLC column using an aqueous mobile phase buffered in the pH range of pH 6.5-7.5. The logarithms of the retention factors are correlated with the Abraham solvation parameter model. The derived correlation contains the five Abraham solute descriptors plus two additional indicator descriptors (I(COOH) and I(amine)) that would be needed whenever carboxylic acid and alkylamine solutes are eluted in ionic form. The derived correlation describes the experimental capacity data of 174 neutral, acidic and basic compounds to within 0.21 log units.