Somatically hypermutated antibodies isolated from SARS-CoV-2 Delta infected patients cross-neutralize heterologous variants.

SARS-CoV-2 Omicron variants feature highly mutated spike proteins with extraordinary abilities in evading antibodies isolated earlier in the pandemic. Investigation of memory B cells from patients primarily with breakthrough infections with the Delta variant enables isolation of a number of neutralizing antibodies cross-reactive to heterologous variants of concern (VOCs) including Omicron variants (BA.1-BA.4). Structural studies identify altered complementarity determining region (CDR) amino acids and highly unusual heavy chain CDR2 insertions respectively in two representative cross-neutralizing antibodies-YB9-258 and YB13-292. These features are putatively introduced by somatic hypermutation and they are heavily involved in epitope recognition to broaden neutralization breadth. Previously, insertions/deletions were rarely reported for antiviral antibodies except for those induced by HIV-1 chronic infections. These data provide molecular mechanisms for cross-neutralization of heterologous SARS-CoV-2 variants by antibodies isolated from Delta variant infected patients with implications for future vaccination strategy.

Emergency department presentations during the COVID-19 pandemic in Queensland (to June 2021): interrupted time series analysis.

OBJECTIVES: To assess emergency department (ED) presentation numbers in Queensland during the coronavirus disease 2019 (COVID-19) pandemic to mid-2021, a period of relatively low COVID-19 case numbers. DESIGN: Interrupted time series analysis. SETTING: All 105 Queensland public hospital EDs. MAIN OUTCOME MEASURES: Numbers of ED presentations during the COVID-19 lockdown period (11 March 2020 - 30 June 2020) and the period of easing restrictions (1 July 2020 - 30 June 2021), compared with pre-pandemic period (1 January 2018 - 10 March 2020), overall (daily numbers) and by Australasian Triage Scale (ATS; daily numbers) and selected diagnostic categories (cardiac, respiratory, mental health, injury-related conditions) and conditions (stroke, sepsis) (weekly numbers). RESULTS: During the lockdown period, the mean number of ED presentations was 19.4% lower (95% confidence interval, -20.9% to -17.9%) than during the pre-pandemic period (predicted mean number: 5935; actual number: 4786 presentations). The magnitudes of the decline and the time to return to predicted levels varied by ATS category and diagnostic group; changes in presentation numbers were least marked for ATS 1 and 2 (most urgent) presentations, and for presentations with cardiac conditions or stroke. Numbers remained below predicted levels during the 12-month post-lockdown period for ATS 5 (least urgent) presentations and presentations with mental health problems, respiratory conditions, or sepsis. CONCLUSIONS: The COVID-19 pandemic and related public restrictions were associated with profound changes in health care use. Pandemic plans should include advice about continuing to seek care for serious health conditions and health emergencies, and support alternative sources of care for less urgent health care needs.

Immune response and homeostasis mechanism following administration of BBIBP-CorV SARS-CoV-2 inactivated vaccine.

The BBIBP-CorV severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) inactivated vaccine has been authorized for emergency use and widely distributed. We used single-cell transcriptome sequencing to characterize the dynamics of immune responses to the BBIBP-CorV inactivated vaccine. In addition to the expected induction of humoral immunity, we found that the inactivated vaccine induced multiple, comprehensive immune responses, including significantly increased proportions of CD16+ monocytes and activation of monocyte antigen presentation pathways; T cell activation pathway upregulation in CD8+ T cells, along with increased activation of CD4+ T cells; significant enhancement of cell-cell communications between innate and adaptive immunity; and the induction of regulatory CD4+ T cells and co-inhibitory interactions to maintain immune homeostasis after vaccination. Additionally, comparative analysis revealed higher neutralizing antibody levels, distinct expansion of naive T cells, a shared increased proportion of regulatory CD4+ T cells, and upregulated expression of functional genes in booster dose recipients with a longer interval after the second vaccination. Our research will support a comprehensive understanding of the systemic immune responses elicited by the BBIBP-CorV inactivated vaccine, which will facilitate the formulation of better vaccination strategies and the design of new vaccines.

An Exploration of Psychological Resilience among Undergraduate Nursing Students Undertaking an Adult Nursing Virtual Practicum during the Coronavirus Pandemic in Taiwan: A Qualitative Study.

This qualitative study aimed to explore the psychological resilience of undergraduate nursing students partaking in a virtual practicum during the coronavirus pandemic (COVID-19) in Taiwan. The virtual practicum, a form of online learning, creates challenges compared to the traditional teaching-learning experience of an actual clinical placement. Exploring how students overcome learning difficulties and build resilience is necessary for a new learning environment or for future online learning. Constructivist grounded theory and the Standards for Reporting Qualitative Research checklist were followed. Purposive and theoretical sampling were used to recruit 18 student nurses for data saturation. Semi-structured, face-to-face interviews were conducted individually to collect data. Initial, focused, and theoretical coding and constant comparative data analysis were performed. Credibility, originality, resonance, and usefulness guided the assessment of the study's quality. The core category of psychological resilience in the virtual practicum was constructed to reflect Taiwanese nursing students' progress and experiences of learning during the virtual practicum. This core category consisted of three subcategories: (i) learning difficulties within one's inner self; (ii) staying positive and confident; and (iii) knowing what is possible. The findings identified psychological resilience as an important factor for students to adjust to the adverse experiences of a rapidly changing learning environment, such as the virtual practicum. The substantive theory of psychological resilience provided a frame of reference for coping with possible future difficulties. Correspondingly, psychological resilience reflected individuals' potential characteristics and may help students to enter and remain in the nursing profession.

Highly sensitive electrochemical aptasensor for SARS-CoV-2 antigen detection based on aptamer-binding induced multiple hairpin assembly signal amplification.

In this work, a brief electrochemical aptasensor was developed for highly sensitive detection of SARS-CoV-2 antigen utilizing an aptamer-binding induced multiple hairpin assembly strategy for signal amplification. In the presence of SARS-CoV-2, a pair of aptamers was brought in a close proximity according to the aptamer-protein antigen binding, which initiated strand displacement reaction thereby triggering a multiple hairpin assembly to obtain long linear DNA concatemers on the electrode surface. As the fabricated hairpin probes were labeled with biotin, massive streptavidin-alkaline phosphatases (ST-ALP) could be further introduced on the electrode interface via biotin-streptavidin interaction thus generating strong electrochemical signal in electrolyte solution containing 1-naphthol phosphate. Benefiting from the non-enzymatic multiple hairpin assembly signal amplification strategy, the designed aptasensor for SARS-CoV-2 spike protein detection exhibited the wide linear range from 50 fg·mL-1 to 50 ng·mL-1 and low detection limit of 9.79 fg·mL-1. Meaningfully, this proposed electrochemical assay provided a potential application for the point of care analysis of viral diseases under ambient temperature.

Innate immune response analysis in COVID-19 and kawasaki disease reveals MIS-C predictors.

BACKGROUND/PURPOSE: The association between dysregulated innate immune responses seen in Kawasaki disease (KD) with predisposition to Kawasaki-like multisystem inflammatory syndrome in children (MIS-C) remains unclear. We aimed to compare the innate immunity transcriptome signature between COVID-19 and KD, and to analyze the interactions of these molecules with genes known to predispose to KD. METHODS: Transcriptome datasets of COVID-19 and KD cohorts (E-MTAB-9357, GSE-63881, GSE-68004) were downloaded from ArrayExpress for innate immune response analyses. Network analysis was used to determine enriched pathways of interactions. RESULTS: Upregulations of IRAK4, IFI16, STING, STAT3, PYCARD, CASP1, IFNAR1 and CD14 genes were observed in blood cells of acute SARS-CoV-2 infections with moderate severity. In the same patient group, increased expressions of TLR2, TLR7, IRF3, and CD36 were also noted in blood drawn a few days after COVID-19 diagnosis. Elevated blood PYCARD level was associated with severe COVID-19 in adults. Similar gene expression signature except differences in TLR8, NLRP3, STING and IRF3 levels was detected in KD samples. Network analysis on innate immune genes and genes associated with KD susceptibility identified enriched pathways of interactions. Furthermore, higher expression levels of KD susceptibility genes HLA-DOB, PELI1 and FCGR2A correlated with COVID-19 of different severities. CONCLUSION: Our findings suggest that most enriched innate immune response pathways were shared between transcriptomes of KD and COVID-19 with moderate severity. Genetic polymorphisms associated with innate immune dysregulation and KD susceptibility, together with variants in STING and STAT3, might predict COVID-19 severity and potentially susceptibility to COVID-19 related MIS-C.