Diagnostic value and characteristic analysis of serum nucleocapsid antigen in COVID-19 patients.

Background: To date, several types of laboratory tests for coronavirus disease 2019 (COVID-19) diagnosis have been developed. However, the clinical importance of serum severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleocapsid antigen (N-Ag) remains to be fully elucidated. In this study, we sought to investigate the value of serum SARS-CoV-2 N-Ag for COVID-19 diagnosis and to analyze N-Ag characteristics in COVID-19 individuals. Methods: Serum samples collected from 215 COVID-19 patients and 65 non-COVID-19 individuals were used to quantitatively detect N-Ag via chemiluminescent immunoassay according to the manufacturer's instructions. Results: The sensitivity and specificity of the N-Ag assay were 64.75% (95% confidence interval (95% CI) [55.94-72.66%]) and 100% (95% CI [93.05-100.00%]), respectively, according to the cut-off value recommended by the manufacturer. The receiver operating characteristic (ROC) curve showed a sensitivity of 100.00% (95% CI [94.42-100.00%]) and a specificity of 71.31% (95% CI [62.73-78.59%]). The positive rates and levels of serum SARS-CoV-2 N-Ag were not related to sex, comorbidity status or disease severity of COVID-19 (all P < 0.001). Compared with RT‒PCR, there was a lower positive rate of serum N-Ag for acute COVID-19 patients (P < 0.001). The positive rate and levels of serum SARS-CoV-2 N-Ag in acute patients were significantly higher than those in convalescent patients (all P < 0.001). In addition, the positive rate of serum SARS-CoV-2 N-Ag in acute COVID-19 patients was higher than that of serum antibodies (IgM, IgG, IgA and neutralizing antibodies (Nab)) against SARS-CoV-2 (all P < 0.001). However, the positive rate of serum SARS-CoV-2 N-Ag in convalescent COVID-19 patients was significantly lower than that of antibodies (all P < 0.001). Conclusion: Serum N-Ag can be used as a biomarker for early COVID-19 diagnosis based on appropriate cut-off values. In addition, our study also demonstrated the relationship between serum N-Ag and clinical characteristics.

Motivating nurses' coworker-directed helping behaviour during the COVID-19 pandemic: Role of managerial humour and nurses' power distance orientation.

AIMS: The aims of the research are to investigate (1) the influence of managerial humour on nurses' coworker-directed helping behaviour, (2) the mediating effect of nurses' feelings of energy between managerial humour and nurses' coworker-directed helping behaviour and (3) the moderating effect of nurses' power distance orientation. DESIGN: This is a quantitative study. A three-wave survey design was conducted to collect data from direct managers to nurse dyads. METHODS: The random sampling method was employed. Data were collected from the supervisor to subordinate dyad at three time points during the first half of 2021. A total of 235 paired data sets of nurses and their direct managers were collected from a large state-owned Chinese hospital. We used hierarchical regression analyses via SPSS 22.0 software to examine the hypotheses. RESULTS: (1) Managerial humour can foster nurses' coworker-directed helping behaviour via accumulating their feelings of energy. (2) Power distance orientation moderates the effect of managerial humour on feelings of energy as well as the indirect effect of managerial humour on nurses' coworker-directed helping behaviour via feelings of energy, in a way that these effects are stronger when nurses have higher (vs. lower) level of power distance orientation. CONCLUSION: Managerial humour can increase nurses' feelings of energy, which in turn, motivates them to help their coworkers. Nurses' power distance orientation is an important boundary condition that constrains managerial humour effectiveness. IMPACT: Hospital managers could use more humour during their interactions with nurses because managerial humour can promote nurses' feelings of energy and coworker-directed helping behaviour. Hospitals can take humour into account during managers' selection and training to improve management effectiveness. Managers in eastern countries should use more humour during their interactions with followers. PATIENT OR PUBLIC CONTRIBUTION: Nurses and their direct managers from a large state-owned Chinese hospital contributed to this study by completing the survey.

COVID-19 pandemic impact on banking sector: A cross-country analysis

This study examines the effects of the COVID-19 outbreak on the performance and stability of the banking sector. Our sample consists of 2073 banks in 106 countries from 2016Q1 to 2021Q2. We employ several alternative bank performance and stability measures for a comprehensive analysis and robustness. The findings show that the COVID-19 outbreak has significantly reduced bank performance and stability. These results are consistently observed across several geographical regions and countries' income classifications. Additional analysis shows that the adverse impact of COVID-19 depends on the characteristics of the bank and market structure. While a better regulatory environment, institutional quality, and financial development have significantly increased the strength and resilience of banks. These findings provide practical implications for regulators and policymakers in the face of unprecedented uncertainty caused by the COVID-19 pandemic.

COVID-19 pandemic impact on banking sector: A cross-country analysis

This study examines the effects of the COVID-19 outbreak on the performance and stability of the banking sector. Our sample consists of 2073 banks in 106 countries from 2016Q1 to 2021Q2. We employ several alternative bank performance and stability measures for a comprehensive analysis and robustness. The findings show that the COVID-19 outbreak has significantly reduced bank performance and stability. These results are consistently observed across several geographical regions and countries' income classifications. Additional analysis shows that the adverse impact of COVID-19 depends on the characteristics of the bank and market structure. While a better regulatory environment, institutional quality, and financial development have significantly increased the strength and resilience of banks. These findings provide practical implications for regulators and policymakers in the face of unprecedented uncertainty caused by the COVID-19 pandemic.

A Systemic Study of Subcellular Localization of Porcine Epidemic Diarrhea Virus Proteins.

Porcine epidemic diarrhea virus (PEDV), a highly pathogenic enteric coronavirus, is regarded as one of the most severe porcine pathogens. To date, there are still no commercial vaccines or drugs that can provide full protection against the epidemic strains. A better understanding of the subcellular location of individual proteins could benefit from studying the protein functions and mechanisms of how the virus regulates key cellular processes, finally leading to the development of antiviral agents. In this study, we characterized the subcellular localization of PEDV proteins using multi-labeled fluorescent immunocytochemistry. As a result, 11 proteins showed cytoplasmic distribution and 10 proteins showed both cytoplasmic and nuclear distribution. Furthermore, we demonstrated that four proteins (Nsp3, Nsp4, Nsp6, and S1) were co-localized in the endoplasmic reticulum (ER), while four proteins (Nsp2, S2, N, and ORF3) were partially observed in the ER, two proteins (E and M) were co-localized in the Golgi apparatus, and two proteins (Nsp2 and E) were partially co-localized with the mitochondria. These viral proteins may perform specific functions at specific cellular locations. Together, these results describe a subcellular localization map of PEDV proteins, which will help to characterize the functions of these proteins in the future.

The common regulatory pathway of COVID-19 and multiple inflammatory diseases and the molecular mechanism of cepharanthine in the treatment of COVID-19.

Background: Similar pathogenesis makes Corona Virus Disease 2019 (COVID-19) associated with rheumatoid arthritis (RA), ankylosing spondylitis (AS) and gouty arthritis (GA), and it is possible to introduce common drugs for the treatment of RA, AS and GA into the treatment of COVID-19. That is, "homotherapy for heteropathy", especially cytokine inhibitors. But little is known about the specific link between the diseases. In addition, "new use of old drugs" is an important short-term strategy for the treatment of COVID-19. Cepharanthine (CEP), a monomer component of traditional Chinese medicine (TCM), is mainly used in the treatment of leukopenia and has recently been proved to have a good therapeutic effect on COVID-19, but its specific molecular mechanism has not been clearly explained. The purpose of this work is to explore the common targets and signaling pathways among COVID-19, RA, AS, and GA by means of network pharmacology (NP), and to infer the potential mechanism of CEP in the treatment of COVID-19. Methods: Firstly, SwissTargetPrediction was used to predict the targets of CEP, and the pathogenic targets of COVID-19, RA, AS and GA were searched in GeneCards, OMIM, TTD, PharmGKB database and literature, respectively. Then, the protein interaction network of CEP and COVID-19 cross targets and the common targets of COVID-19, RA, AS and GA was constructed. Cytosscape 3.7.2 software was used to construct CEP-common targets-signaling pathways-COVID-19 network, module function analysis, gene ontology (GO) and kyoto encyclopedia of genes and genomes (KEGG). Finally, the molecular docking of hub targets and CEP was carried out by AutoDock software. Results: The results showed that the common targets of the four diseases were tumor necrosis factor (TNF), interleukin (IL)-6 and IL-1ß, and involved Coronavirus disease, IL-17 signaling pathway and TNF signaling pathway. CEP has a good binding force with AKT Serine/Threonine Kinase 1 (AKT1), phosphatidylinositol 3-kinase (PIK3) CA, PIK3CD and Angiotensin-converting enzyme 2 (ACE2), and plays a role in the treatment of COVID-19 by regulating PI3K-Akt signaling pathway, Relaxin signaling pathway, VEGF signaling pathway and HIF-1 signaling pathway. Conclusion: Therefore, this study not only confirmed the potential mechanism of CEP in the treatment of COVID-19 at the molecular level, but also found that TNF and IL-17 inhibitors, which are commonly used in the treatment of RA, AS and GA, may also affect the treatment of COVID-19, which provides new clues and theoretical basis for the rapid discovery of effective therapeutic drugs for COVID-19.

Establishment and application of dual TaqMan fluorescent quantitative PCR assay for Senecavirus A and encephalomyocarditis virus

In order to establish a method for rapid differential identification of Senecavirus A (SVA) and en-cephalomyocarditis virus (EMCV), two pairs of corresponding specific primers were designed based on the highly conserved 3D genes of SVA and EMCV. And two different fluorescent labeled TaqMan probes were used to establish a dual TaqMan real-time PCR method for simultaneous detection of these two viruses, and we also optimize the reaction conditions. The results showed that the minimum detection of the method was 760 copies/ micro L and 98 copies/ micro L for SVA and EMCV. respectively, and it can specifically detect SVA and EMCV, and there was no cross reaction with CSFV, PRRSV and PEDV. The established standard curves showed good linear relationship. Repeated experimental group and inter-group coefficient of variation were less than 5%. The results indicated that the dual-quantitative PCR established in this study has the advantages of convenience, rapidity, good specificity. high sensitivity and good repeatability .and can be used for simultaneous detection of SVA and EMCV.

The common regulatory pathway of COVID-19 and multiple inflammatory diseases and the molecular mechanism of cepharanthine in the treatment of COVID-19

Background: Similar pathogenesis makes Corona Virus Disease 2019 (COVID-19) associated with rheumatoid arthritis (RA), ankylosing spondylitis (AS) and gouty arthritis (GA), and it is possible to introduce common drugs for the treatment of RA, AS and GA into the treatment of COVID-19. That is, “homotherapy for heteropathy”, especially cytokine inhibitors. But little is known about the specific link between the diseases. In addition, “new use of old drugs” is an important short-term strategy for the treatment of COVID-19. Cepharanthine (CEP), a monomer component of traditional Chinese medicine (TCM), is mainly used in the treatment of leukopenia and has recently been proved to have a good therapeutic effect on COVID-19, but its specific molecular mechanism has not been clearly explained. The purpose of this work is to explore the common targets and signaling pathways among COVID-19, RA, AS, and GA by means of network pharmacology (NP), and to infer the potential mechanism of CEP in the treatment of COVID-19. Methods: Firstly, SwissTargetPrediction was used to predict the targets of CEP, and the pathogenic targets of COVID-19, RA, AS and GA were searched in GeneCards, OMIM, TTD, PharmGKB database and literature, respectively. Then, the protein interaction network of CEP and COVID-19 cross targets and the common targets of COVID-19, RA, AS and GA was constructed. Cytosscape 3.7.2 software was used to construct CEP-common targets-signaling pathways-COVID-19 network, module function analysis, gene ontology (GO) and kyoto encyclopedia of genes and genomes (KEGG). Finally, the molecular docking of hub targets and CEP was carried out by AutoDock software. Results: The results showed that the common targets of the four diseases were tumor necrosis factor (TNF), interleukin (IL)-6 and IL-1β, and involved Coronavirus disease, IL-17 signaling pathway and TNF signaling pathway. CEP has a good binding force with AKT Serine/Threonine Kinase 1 (AKT1), phosphatidylinositol 3-kinase (PIK3) CA, PIK3CD and Angiotensin-converting enzyme 2 (ACE2), and plays a role in the treatment of COVID-19 by regulating PI3K-Akt signaling pathway, Relaxin signaling pathway, VEGF signaling pathway and HIF-1 signaling pathway. Conclusion: Therefore, this study not only confirmed the potential mechanism of CEP in the treatment of COVID-19 at the molecular level, but also found that TNF and IL-17 inhibitors, which are commonly used in the treatment of RA, AS and GA, may also affect the treatment of COVID-19, which provides new clues and theoretical basis for the rapid discovery of effective therapeutic drugs for COVID-19.

Effects of Cell Phone Dependence on Mental Health Among College Students During the Pandemic of COVID-19: A Cross-Sectional Survey of a Medical University in Shanghai.

Objective: To investigate the effects of cell phone dependence (CPD) on mental health among undergraduates during the COVID-19 pandemic and further identify the determinants that may affect their mental health in China. Methods: The data were collected from 602 students at a medical school in Shanghai via an online survey conducted from December 2021 to February 2022. The Mobile Phone Addiction Index (MPAI) and Depression Anxiety Stress Scale (DASS) were applied to evaluate CPD and mental health, respectively. Independent sample t-test and one-way analysis of variance (ANOVA) were employed to compare the means of continuous variables among categorical groups. Correlations between continuous variables were detected using Pearson's correlation analysis. Univariable and multivariable logistic regressions were employed to identify the determinants of mental health. Results: Among the 402 eligible students, 73.88% were women with an average age of 20.19 ± 2.36 years. On average, the DASS score was 32.20 ± 11.07, the CPD score was 36.23 ± 11.89, and the cell phone use duration was 7.67 ± 3.61 h/day. CPD was found to have a negative effect on mental health among college students in Shanghai. Additionally, cell phone use duration, age, being senior students, faculty-student relationship, insomnia, tobacco use, obesity, and life satisfaction were clarified as contributing factors to mental health among college students. Conclusion: High degree of CPD could have a negative effect on college students' mental health, which might lead to some psychological problems. Appropriate actions and effective interventions are highly needed to prevent severe psychological injuries among college students in China.

Delta Infection After Vaccination Elicits Potent Neutralizing Immunity Against Severe Acute Respiratory Syndrome Coronavirus 2 Omicron.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron (B.1.1.529) variant extensively escape neutralizing antibodies by vaccines or infection. We assessed serum neutralizing activity in sera from Delta infection after vaccination and Delta infection only against SARS-CoV-2 Wuhan-Hu-1 (WA1), Beta, Delta, and Omicron. Sera from Delta infection only could neutralize WA1 and Delta but almost completely lost capacity to neutralize Beta and Omicron. However, Delta infection after vaccination resulted in a significant increase of serum neutralizing activity against WA1, Beta, and Omicron. This study demonstrates that breakthrough infection of Delta substantially induced high potency humoral immune response against the Omicron variant and other emerged variants.

Natural Compound ZINC12899676 Reduces Porcine Epidemic Diarrhea Virus Replication by Inhibiting the Viral NTPase Activity.

Porcine epidemic diarrhea virus (PEDV) is an alphacoronavirus (α-CoV) that causes high mortality in suckling piglets, leading to severe economic losses worldwide. No effective vaccine or commercial antiviral drug is readily available. Several replicative enzymes are responsible for coronavirus replication. In this study, the potential candidates targeting replicative enzymes (PLP2, 3CLpro, RdRp, NTPase, and NendoU) were screened from 187,119 compounds in ZINC natural products library, and seven compounds had high binding potential to NTPase and showed drug-like property. Among them, ZINC12899676 was identified to significantly inhibit the NTPase activity of PEDV by targeting its active pocket and causing its conformational change, and ZINC12899676 significantly inhibited PEDV replication in IPEC-J2 cells. It first demonstrated that ZINC12899676 inhibits PEDV replication by targeting NTPase, and then, NTPase may serve as a novel target for anti-PEDV.

Application of 2019 Novel Coronavirus (2019-nCoV) specific antibody detection for suspected cases screening

Comparing the accuracy of antibody detection reagents which based on different principles by the diagnosis of suspected cases of new crown, propose an efficient screening plan for suspected cases, and further provide a scientific basis for establishing a clinical screening path for high-risk populations. For 76 suspected cases of COVID-19 that were transferred to designated hospitals for isolation and observation due to the initial IgM antibody test, nasopharyngeal swab nucleic acid tests, serum trace virus neutralizing antibodies and three commercially available antibody test reagents with different principles were tested, combined with lung CT and the examination and clinical symptoms or other information, comprehensively judge the diagnosis or exclusion of the new crown, and compare the three kinds of serological antibody detection reagents with the clinical judgment results to compare the detection rates of the three detection methods. Through comprehensive judgment, 3 suspected cases are confirmed cases, and 73 suspected cases are excluded cases. Compared with the clinical diagnosis/exclusion results, among the three serological antibody detection methods, the chemiluminescence total antibody kit detect positive for all the 9 serums collected from the 3 confirmed cases in different time points, the detection specificity is 97.26% for 73 excluded cases, it's significantly higher than that of the chemiluminescence method IgM/IgG and the colloidal gold method IgM/IgG Separate testing (the specificity is 73.97% on the first day of admission). The chemiluminescence method for the detection of total antibodies to the 2019-nCoV has high sensitivity and high specificity, and can be used for preliminary screening of antibody detection in suspected cases. For the screening of target populations, the 2019-nCoV nucleic acid test should be performed first. If the nucleic acid test is negative, the screening path with the detection of serum total antibodies as the main indicator should be adopted.

A rare case of drug-induced bradycardia associated with the just low dose use of methylprednisolone in a child with COVID-19.

Methylprednisolone (MP) is usually used to reduce inflammation reaction and tissue damage, which may have a beneficial treatment effect on coronavirus disease 2019 (COVID-19). However, we present the case of a child who manifests significant bradycardia with the use of just low dose MP on the premise of the long-term use of arbidol. Arbidol can affect the activity of CYP3A4, which is also a key metabolic enzyme of MP by competitive inhibition, and which is easy to aggravate the side effects of MP. Therefore, more attention should be paid to bradycardia occurrence in the patient with COVID-19 when MP is considered in COVID-19.

Governmental Inter-sectoral Strategies to Prevent and Control COVID-19 in a Megacity: A Policy Brief From Shanghai, China

This policy brief aims to help policymakers develop inter-sectoral interventions in megacities to prevent and control COVID-19. Based on the case of Changning District in Shanghai, China, several policy options are identified. The guiding principles include ensuring a coordinated national response (i.e., moderation is required in epidemic prevention and control);making science-based, precise, and differentiated epidemic control strategies;and establishing a joint prevention and control mechanism. Policy tools include localized management, closed-loop management, community grid management, digital management, and sub-population management. There is no “one size fits all” policy;however, it will be helpful to learn by trial and error through on-the-ground experience with minimal information in real time.

Essential Oil-Rich Chinese Formula Luofushan-Baicao Oil Inhibits the Infection of Influenza A Virus through the Regulation of NF-κB P65 and IRF3 Activation.

BACKGROUND: Luofushan-Baicao Oil (LBO) is an essential oil-rich traditional Chinese medicine (TCM) formula that is commonly used to treat cold, cough, headache, sore throat, swelling, and pain. However, the anti-influenza activities of LBO and the underlying mechanism remain to be investigated. METHODS: The in vitro anti-influenza activity of LBO was tested with methyl thiazolyl tetrazolium (MTT) and plaque assays. The effects of LBO on the expressions of viral nucleoprotein and cytokines were evaluated. In the polyinosinic-polycytidylic acid- (Poly I: C-) induced inflammation model, the influences of LBO on the expression of cytokines and the activation of NF-κB P65 (P65) and interferon regulatory factor 3 (IRF3) were tested. After influenza A virus (IVA) infection, mice were administered with LBO for 5 days. The lung index, histopathologic change, the expression of viral protein, P65, and IRF3 in the lung tissue were measured. The levels of proinflammatory cytokines in serum were examined. RESULTS: In vitro, LBO could significantly inhibit the infection of IVA, decrease the formation of plaques, and reduce the expression of viral nucleoprotein and cytokines. LBO could also effectively downregulate the expression of interleukin-1ß (IL-1ß), interleukin-6 (IL-6), and interferon-ß and the activation of P65 and IRF3 in Poly I:C-treated cells. In the IVA-infected mice model, inhalation of LBO with atomizer could decrease the lung index, alleviate the pathological injury in the lung tissue, and reduce the serum levels of IL-1ß and IL-6. LBO could significantly downregulate the expression of viral protein (nucleoprotein, PB2, and matrix 2 ion channel) and the phosphorylation of P65 and IRF3 in the lungs of mice. CONCLUSION: The therapeutic effects of LBO on treating influenza might result from the regulation of the immune response of IVA infection. LBO can be developed as an alternative therapeutic agent for influenza prevention.

Retrospectively analysis the Guangdong's experience on how to transport potential infected passengers by chartered aircraft during outbreaks of COVID- 19

Objective To summarize the experience of five hospitals in Guangdong Province 0n successfully transporting retained passengers by chartered flights during the outbreak of the COVID-19. Methods We retrospectively evaluated the operation and management, cabin arrangement, isolation requirements, and personnel protection in the aspect of epidemic prevention and control. Results In 11 charter missions, over one thousand "healthy" passengers with potential risk of infections were transported back to China. The medical delivery team and flight crew were kept free of infection, passengers maintained zero cluster infections and no unexpected adverse events during the air transport. Conclusions Our results indicate how to carry passengers in a scientific and orderly way is crucial for avoiding the transmission risks of the epidemic of COVID-19 among working staffers and passengers.

Bioinformatic prediction of immunodominant regions in spike protein for early diagnosis of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

BACKGROUND: To contain the pandemics caused by SARS-CoV-2, early detection approaches with high accuracy and accessibility are critical. Generating an antigen-capture based detection system would be an ideal strategy complementing the current methods based on nucleic acids and antibody detection. The spike protein is found on the outside of virus particles and appropriate for antigen detection. METHODS: In this study, we utilized bioinformatics approaches to explore the immunodominant fragments on spike protein of SARS-CoV-2. RESULTS: The S1 subunit of spike protein was identified with higher sequence specificity. Three immunodominant fragments, Spike56-94, Spike199-264, and Spike577-612, located at the S1 subunit were finally selected via bioinformatics analysis. The glycosylation sites and high-frequency mutation sites on spike protein were circumvented in the antigen design. All the identified fragments present qualified antigenicity, hydrophilicity, and surface accessibility. A recombinant antigen with a length of 194 amino acids (aa) consisting of the selected immunodominant fragments as well as a universal Th epitope was finally constructed. CONCLUSION: The recombinant peptide encoded by the construct contains multiple immunodominant epitopes, which is expected to stimulate a strong immune response in mice and generate qualified antibodies for SARS-CoV-2 detection.

The seroprevalence and kinetics of IgM and IgG in the progression of COVID-19.

BACKGROUND: SARS-CoV-2 is a novel coronavirus first recognized in late December 2019 that causes coronavirus disease 19 (COVID-19). Due to the highly contagious nature of SARS-CoV-2, it has developed into a global pandemic in just a few months. Antibody testing is an effective method to supplement the diagnosis of COVID-19. However, multicentre studies are lacking to support the understanding of the seroprevalence and kinetics of SARS-CoV-2 antibodies in COVID-19 epidemic regions. METHOD: A multicentre cross-sectional study of suspected and confirmed patients from 4 epidemic cities in China and a cohort study of consecutive follow-up patients were conducted from 29/01/2020 to 12/03/2020. IgM and IgG antibodies elicited by SARS-CoV-2 were tested by a chemiluminescence assay. Clinical information, including basic demographic data, clinical classification, and time interval from onset to sampling, was collected from each centre. RESULTS: A total of 571 patients were enrolled in the cross-sectional study, including 235 COVID-19 patients and 336 suspected patients, each with 91.9%:2.1% seroprevalence of SARS-CoV-2 IgG and 92.3%:5.4% seroprevalence of SARS-CoV-2 IgM. The seroprevalence of SARS-CoV-2 IgM and IgG in COVID-19 patients was over 70% less than 7 days after symptom onset. Thirty COVID-19 patients were enrolled in the cohort study and followed up for 20 days. The peak concentrations of IgM and IgG were reached on the 10th and 20th days, respectively, after symptom onset. The seroprevalence of COVID-19 IgG and IgM increased along with the clinical classification and treatment time delay. CONCLUSION: We demonstrated the kinetics of IgM and IgG SARS-CoV-2 antibodies in COVID-19 patients and the association between clinical classification and antibodies, which will contribute to the interpretation of IgM and IgG SARS-CoV-2 antibody tests and in predicting the outcomes of patients with COVID-19.

Rapid Development of SARS-CoV-2 Spike Protein Receptor-Binding Domain Self-Assembled Nanoparticle Vaccine Candidates.

The coronavirus disease pandemic of 2019 (COVID-19) caused by the novel SARS-CoV-2 coronavirus resulted in economic losses and threatened human health worldwide. The pandemic highlights an urgent need for a stable, easily produced, and effective vaccine. SARS-CoV-2 uses the spike protein receptor-binding domain (RBD) to bind its cognate receptor, angiotensin-converting enzyme 2 (ACE2), and initiate membrane fusion. Thus, the RBD is an ideal target for vaccine development. In this study, we designed three different RBD-conjugated nanoparticle vaccine candidates, namely, RBD-Ferritin (24-mer), RBD-mi3 (60-mer), and RBD-I53-50 (120-mer), via covalent conjugation using the SpyTag-SpyCatcher system. When mice were immunized with the RBD-conjugated nanoparticles (NPs) in conjunction with the AddaVax or Sigma Adjuvant System, the resulting antisera exhibited 8- to 120-fold greater neutralizing activity against both a pseudovirus and the authentic virus than those of mice immunized with monomeric RBD. Most importantly, sera from mice immunized with RBD-conjugated NPs more efficiently blocked the binding of RBD to ACE2 in vitro, further corroborating the promising immunization effect. Additionally, the vaccine has distinct advantages in terms of a relatively simple scale-up and flexible assembly. These results illustrate that the SARS-CoV-2 RBD-conjugated nanoparticles developed in this study are a competitive vaccine candidate and that the carrier nanoparticles could be adopted as a universal platform for a future vaccine development.

Clinical, laboratory and imaging predictors for critical illness and mortality in patients with COVID-19: protocol for a systematic review and meta-analysis.

INTRODUCTION: With the threat of a worldwide pandemic of COVID-19, it is important to identify the prognostic factors for critical conditions among patients with non-critical COVID-19. Prognostic factors and models may assist front-line clinicians in rapid identification of high-risk patients, early management of modifiable factors, appropriate triaging and optimising the use of limited healthcare resources. We aim to systematically assess the clinical, laboratory and imaging predictors as well as prediction models for severe or critical illness and mortality in patients with COVID-19. METHODS AND ANALYSIS: All peer-reviewed and preprint primary articles with a longitudinal design that focused on prognostic factors or models for critical illness and mortality related to COVID-19 will be eligible for inclusion. A systematic search of 11 databases including PubMed, EMBASE, Web of Science, Cochrane Library, CNKI, VIP, Wanfang Data, SinoMed, bioRxiv, Arxiv and MedRxiv will be conducted. Study selection will follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Data extraction will be performed using the modified version of the Critical Appraisal and Data Extraction for Systematic Reviews of Prediction Modelling Studies checklist and quality will be evaluated using the Newcastle-Ottawa Scale and the Quality In Prognosis Studies tool. The association between prognostic factors and outcomes of interest will be synthesised and a meta-analysis will be conducted with three or more studies reporting a particular factor in a consistent manner. ETHICS AND DISSEMINATION: Ethical approval was not required for this systematic review. We will disseminate our findings through publication in a peer-reviewed journal. PROSPERO REGISTRATION NUMBER: CRD 42020178798.