A bibliometric analysis of personal protective equipment and COVID-19 researches (preprint)

Background: COVID-19, which occurred at the end of December 2019, has evolved into a global public health threat. COVID-19’s high infectivity and mortality prompt governments and scientific community to respond quickly to the outbreak of the pandemic. The application of personal protective equipment (PPE) is of great significance in overcoming the epidemic situation. Although there were many studies about PPE and COVID-19, there is no study about bibliometric analysis of these studies. This study aims to provide a general overview of studies on PPE and COVID-19. Methods: On October 07, 2021, the Web of Science (WOS) Core Collection database was used to identify documents on PPE and COVID-19. HistCite and VOSviewer softwares were used for citation analysis and visualization mapping. Results: A total of 1462 documents authored by 6993 authors and published in 750 journals were included in the final analysis. The most prolific author was Macintyre CR. The USA was the most productive country with 463 published documents. The leading journal was Plos One. Network visualization map showed that USA was the largest international collaboration network. The keyword “COVID-19” had the strongest total link strengths (TLS) and largest number of occurrences. The New England Journal of Medicine was the leading source with highest TLS. The University of Toronto had the highest number of links and the highest TLS. Conclusions: The bibliometric analysis of PPE and COVID-19 provides an overall perspective, and the appreciation and study of these influential publications are very useful for future research.

Balancing Flexibility and Compliance in Response to Long-Tailed Business Process Changes (preprint)

The resilience of process-aware information systems (PAIS) is vital for enterprises' competitiveness in the ever-changing world. Enterprises need continuously maintain business processes in PAIS against uncertainty, resulting in the constant research topic of change management in business process management (BPM). However, previous efforts have left some gaps in dealing with uncertainties in change requirements, either due to high costs or technical incapability. Among these gaps, long-tailed change (LTC), characterized as the urgent and customizable maintenance needs in response to the residual uncertainty, has been largely undeveloped. COVID-19 and some emergent events in 2022 call for more effective solutions to such problems, to mitigate the business loss and to seek emerging opportunities. LTC challenges come from the contention between the degree of flexibility and compliance with business regulations in the context of rapid adaptation. In this paper, we develop a systematic approach to deal with these issues. First, we formulate the problem as a cooperation of multiple participants in the business by leveraging the separation of concerns principle to clarify the division of labor contributing to agility and fine-tuning capability of the approach, and to provide a controllable mechanism to balance operational resilience and dependable adaptation for PAIS. According to the framework, we develop a domain-specific language (DSL) and corresponding techniques to support business people in customizing business processes' behavior to meet circumstances. At the same time, business stakeholders can enforce core functions and service-level agreement (SLA) constraints on the whole business process. We validate our framework through two scenarios, one for design-time model adaptation and the other for run-time instance adaptation. These experiments reveal promising potentials of the framework in adapting to LTC and resolving the contention between agility/flexibility in change and compliance with business regulations, which significantly improves PAIS's resilience to wide-spectrum, low-frequent, sporadic, and transitory events.

Study on prescription medication mode and mechanism of traditional Chinese medicine in the treatment of noncritical COVID-19 based on data mining

Background: As of 2023, coronavirus disease 2019 (COVID-19) is still spreading globally. Therefore, we aim to integrate non-critical COVID-19 high-frequency and high-targeting Chinese medicines to provide a reference for clinical prescriptions to improve COVID-19-related symptoms. Materials and methods: The information on non-critical COVID-19 high-frequency Chinese medicines in the diagnosis and treatment of COVID-19 was obtained by the TCM inheritance support platform. Using network pharmacology and molecular docking technology, high-targeting Chinese medicines with good docking activity with COVID-19 receptors angiotensin-converting enzyme-II (ACE2), 3CLpro and tyrosine-protein kinase receptor UFO (AXL) were obtained. A new prescription for non-critical COVID-19 was established by integrating high-frequency and high-targeting Chinese medicines. Rats with acute lung injury induced by lipopolysaccharide were used as the experimental model. The histopathological changes in the lungs of rats in each group were observed by hematoxylin-eosin staining. The lung coefficient of rats was measured. The levels of IL-6, TNF-a, and IL-1ß in serum were detected by enzyme-linked immunosorbent assay. The mRNA and protein levels of ACE2 and AXL in lung tissue were detected by real-time quantitative polymerase chain reaction and western blot. Results: Through data mining, it was found that there were 39 high-frequency traditional Chinese medicines for non-critical COVID-19 in the diagnosis and treatment guidelines. According to network pharmacology and molecular docking, 30 highly targeted traditional Chinese drugs for COVID-19 were found. The new prescriptions for non-critical COVID-19 were comprehensively obtained, including Glycyrrhizae Radix, Ephedra Herba, Amygdalus Communis Vas, Gypsum Fibrosum, Descurainiae Semen, Atractylodes Lancea, Scutellariae Radix, Amomum Tsao-Ko Crevostet, Forsythiae Fructus, Pogostemon cablin, Magnolia Officinalis. Compared with the LPS-induced lung injury model group, the medium dose of the new prescription group had significantly alleviated pathological changes in lung tissue, decreased lung coefficient, decreased contents of IL-6, TNF-a and IL-1ß, and increased mRNA and protein expression of ACE2 and AXL (P < 0.05). Conclusion: Based on data mining, network pharmacology and molecular docking technology, the new prescription for non-critical COVID-19 established by this method has an anti-inflammatory effect on rats with acute lung injury induced by lipopolysaccharide and can provide a reference for clinicians to alleviate the symptoms related to non-critical COVID-19. [ FROM AUTHOR] Copyright of Traditional Medicine Research is the property of TMR Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)

Impact of lockdown policies during the COVID-19 outbreak on a trauma center of a tertiary hospital in China.

BACKGROUND: Coronavirus disease 2019 (COVID-19) is a major and costly public health emergency. AIM: To investigate the impact of China's lockdown policies during the COVID-19 outbreak on the level I trauma center of a tertiary comprehensive hospital of Traditional Chinese Medicine. METHODS: All patients admitted to our trauma center during a lockdown in 2020 and the same period in 2019 were enrolled. We collected data on demographics, daily visits, injury type, injury mechanism, injury severity score, and patient management for comparative analysis. RESULTS: The total number of patients in the trauma center of our hospital decreased by 50.38% during the COVID-19 Lockdown in 2020 compared to the same period in 2019. The average number of trauma visits per day in 2019 was 47.94, compared to 23.79 in 2020. Comparing the patients' demographic data, loss of employment was the most predominate characteristic in 2020 compared to 2019, while there was no significant difference in gender, age, and marital status between both periods. During the lockdown period, the proportion of traffic accident-related injuries, injuries due to falls greater than 1.5 m, and mechanical injuries decreased significantly, whereas the proportion of injuries caused by falls less than 1.5 m, cuts, assault, bites, and suicidal tendencies and other injuries increased relatively. In addition, the proportion of patients with minor injuries increased and serious injuries decreased during the lockdown. The hospitalization rate increased significantly, and there was no significant difference in emergency surgery and death rates. CONCLUSION: The lockdown policies during the COVID-19 outbreak significantly altered the number and mechanism of traumatic events in our hospital, which can be monitored regularly. Our results suggest that mandatory public health prevention and control measures by the government can reduce the incidence of traumatic events and the severity of traumatic injuries. Emergency surgery and mortality rates remain high, increased because of factors such as family injury and penetrating injury, and hospitalization rates have increased significantly. Therefore, our trauma center still needs to be fully staffed. Finally, from the perspective of the injury mechanism, indoor trauma is a major risk during a lockdown, and it is particularly important to develop prevention strategies for such trauma to reduce the medical burden of the next catastrophic epidemic.

Perceived Social Support, Psychological Capital, and Subjective Well-Being among College Students in the Context of Online Learning during the COVID-19 Pandemic

This study examined the relationship between perceived social support and subjective well-being among college students in the context of online learning during the COVID-19 pandemic. 515 college students in China that participated in an online questionnaire investigation were selected as the research sample. The results showed that perceived social support was significantly and positively associated with life satisfaction and positive affect and was significantly and negatively related to negative affect among college students learning online during the COVID-19 pandemic. Psychological capital (PsyCap) significantly mediated the relationships between perceived social support and three subjective well-being variables. The present study provides some implications to protect college students' subjective well-being in the context of online learning during the COVID-19 pandemic.

Effects of prone position versus usual care on acute hypoxaemic respiratory failure in patients with COVID‑19: a systematic review and meta-analysis of randomized controlled trials (preprint)

Background: Previous studies have shown that prone position may be beneficial for the treatment of acute respiratory distress syndrome (ARDS) or acute hypoxic respiratory failure (AHRF) in COVID-19 patients, but the results are not consistent, especially in terms of oxygenation outcomes and intubation rate. This systematic review and meta-analysis assessed the effects of prone position on AHRF in COVID-19 patients with all randomized controlled trials (RCTs). Methods: An extensive search of online databases, including MEDLINE, Embase, Web of Science and Cochrane Central Register of Controlled Trials from December 1, 2019 to October 30, 2022, with no language restrictions. This systematic review and meta-analysis are based on the PRISMA statement and has been registered on the International Prospective Register of Systematic Reviews (PROSPERO) with the registered ID: CRD42022367885. We only included RCTs and used Cochrane risk assessment tool for quality assessment. Results: Twelve RCTs fulfilled the selection criteria and 3154 patients were included. Meta-analysis found that patients in prone position group had more significant improvement in the SpO2/FiO2 ratio (mean difference [MD]: 29.76; 95% confidence interval [CI]: 1.39 to 48.13; P=0.001) compared with usual care. Prone position also reduced the need for intubation (odd ratio [OR]: 0.72; 95% CI: 0.62 to 0.85; P＜0.0001; I2=0%). There was no significant difference in mortality, hospital length of stay, incidence of intensive care unit (ICU) admission and adverse events between the two groups. Conclusions: Prone position was a promising intervention method, which is beneficial to improve the oxygenation of patients with ARDS or AHRF caused by COVID-19 and can reduce the need for intubation. However, prone position had no significant difference in mortality, hospital length of stay, incidence of ICU admission and adverse events.

The Face Mask-Associated Dry Eye Symptoms in Workers Who Collecting Novel Coronavirus Nucleic Acid Sample During the Covid-19 Outbreak (preprint)

Objectives To evaluate the impact of face mask wearing on dry eye symptoms in health care professionals who collecting novel coronavirus nucleic acid sample during Omicron outbreak.Methods This cross-sectional online survey enrolled a total of 1135 health workers and social workers who were dispatched to the front line to participate in the fight against the epidemic. The ocular surface disease index (OSDI) questionnaire was also administered to quantify Mask-Associated Dry Eye (MADE) symptoms. The difference between wearing the face shield and safety-goggle was also investigated.Results In this study, the average score was 13.39 (3.39–23.39) and the prevalence of MADE symptoms including mild (23.62%), moderate (12.8%) and severe (4.09%) in Face Shield Group and mild (22.00%), moderate (11.67%) and severe (2.67%) in Safety-Goggles Group. The prevalence of MADE symptoms was higher in female (41.80%) and 50–65 age (64.65%).Conclusions A proportion of health and social workers suffer from dry eye symptoms related with wearing mask during the COVID-19 outbreak. MADE interventions should be implemented among health workers during the COVID-19 outbreak to reduce MADE symptoms effects and prevent long-term adverse outcomes.

Intranasal delivery of NS1-deleted influenza virus vectored COVID-19 vaccine restrains the SARS-CoV-2 inflammatory response (preprint)

The emergence of SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus-2) variants and "anatomical escape" characteristics threaten the effectiveness of current coronavirus disease (COVID-19) vaccines. There is an urgent need to understand the immunological mechanism of broad-spectrum respiratory tract protection to guide broader vaccines development. In this study, we investigated immune responses induced by an NS1-deleted influenza virus vectored intranasal COVID-19 vaccine (dNS1-RBD) which provides broad-spectrum protection against SARS-CoV-2 variants. Intranasal delivery of dNS1-RBD induced innate immunity, trained immunity and tissue-resident memory T cells covering the upper and lower respiratory tract. It restrained the inflammatory response by suppressing early phase viral load post SARS-CoV-2 challenge and attenuating pro-inflammatory cytokine (IL-6, IL-1B, and IFN-{gamma}) levels, thereby reducing excess immune-induced tissue injury compared with the control group. By inducing local cellular immunity and trained immunity, intranasal delivery of NS1-deleted influenza virus vectored vaccine represents a broad-spectrum COVID-19 vaccine strategy to reduce disease burden.

The crystal structure and transformations of the omicron phase Ο in the Ti-Al-Nb system and on the ambiguity of its subvariants Ο1 and Ο2

Omicron, Ο-Ti 2 NbAl alloys have been under continuous development for more than 40 years as potential materials for the gas turbine engine;however, the crystal structure and phase transformations are still unclear. In this work, we clarified the crystal structure, atom positions and phase transformations of the Ο phase by in-situ neutron diffraction and high-temperature X-ray diffraction methods. From room temperature to the vanishing temperature of the Ο phase, the latter exposes a C m c m structure, with Ti and Nb atoms tending to respectively occupy the 8g and 4c 2 positions, but with a certain disorder, introducing an order parameter. The phase transformation sequences of Ti-24.8Al-24.3Nb alloy are Ο(975 °C) → β o + Ο(997.5 °C) → β o (1165.5 °C) → β. Moreover, we have proven that a distinction of the omicron subvariants Ο1 and Ο2 is crystallographic nonsense as Ο1 must equal to α 2 of P 6 3 /m m c structure, and Ti 2 NbAl is a prototype structure by itself. [Display omitted] [ FROM AUTHOR] Copyright of Scripta Materialia is the property of Pergamon Press - An Imprint of Elsevier Science and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)

A live attenuated influenza virus-vectored intranasal COVID-19 vaccine provides rapid, prolonged, and broad protection against SARS-CoV-2 infection (preprint)

Remarkable progress has been made in developing intramuscular vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2); however, they are limited with respect to eliciting local immunity in the respiratory tract, which is the primary infection site for SARS-CoV-2. To overcome the limitations of intramuscular vaccines, we constructed a nasal vaccine candidate based on an influenza vector by inserting a gene encoding the receptor-binding domain (RBD) of the spike protein of SARS-CoV-2, named CA4-dNS1-nCoV-RBD (dNS1-RBD). A preclinical study showed that in hamsters challenged 1 day and 7 days after single-dose vaccination or 6 months after booster vaccination, dNS1-RBD largely mitigated lung pathology, with no loss of body weight, caused by either the prototype-like strain or beta variant of SARS-CoV-2. Lasted data showed that the animals could be well protected against beta variant challenge 9 months after vaccination. Notably, the weight loss and lung pathological changes of hamsters could still be significantly reduced when the hamster was vaccinated 24 h after challenge. Moreover, such cellular immunity is relatively unimpaired for the most concerning SARS-CoV-2 variants. The protective immune mechanism of dNS1-RBD could be attributed to the innate immune response in the nasal epithelium, local RBD-specific T cell response in the lung, and RBD-specific IgA and IgG response. Thus, this study demonstrates that the intranasally delivered dNS1-RBD vaccine candidate may offer an important addition to fight against the ongoing COVID-19 pandemic, compensating limitations of current intramuscular vaccines, particularly at the start of an outbreak.

Milk Small Extracellular Vesicles-derived miRNAs Restrict Porcine Epidemic Diarrhea Virus Infectivity (preprint)

Background: Virus-caused diseases are a huge challenge to both animals and human beings, especially coronaviruses. Porcine epidemic diarrhea virus (PEDV), a coronavirus, causes acute diarrhea and up to 100% mortality in piglets less than three weeks of age. Maternal immunity provides protection for piglets in resisting PEDV infection. Small extracellular vesicles (sEV) contain bioactive molecules such as miRNAs to exchange genetic and epigenetic information between cells. Our previous study suggested that milk sEV facilitated intestinal tract development and prevented LPS-induced intestine damage. However, the effects of milk sEV on the inhibition of viral infections remain unclear. Results: In this study, through in vivo experiments, we found that porcine milk sEV protected piglets from PEDV-induced diarrhea and death. In vitro, we clarified that this protective effect was partly generated through the inhibition of the PEDV-N protein and HMGB1 by sEV miR-let-7e and miR-27b, respectively. Conclusions: In conclusion, we report that porcine milk sEVs protected piglets from PEDV-induced diarrhea and death by inhibiting virus replication, and this protective effect was partly generated through the inhibition of the PEDV-N and HMGB1 pathways by exosomal miR-let-7e and miR-27b. This study reveals a new antiviral function of milk sEVs, and the results suggest that milk sEVs may act as a mother-offspring transmission pathway for protecting newborns against PEDV infection.

Both Baicalein and Gallocatechin Gallate Efficaciously Inhibit SARS-CoV-2 Replication by Targeting Mpro and Sepsis in Mice (preprint)

Severe acute syndrome coronavirus 2(SARS-CoV-2) caused the global pandemic of COVID-19 since December 2019. Although most of COVID-19’s patients are mild or common, most of the severe patients have sepsis caused by the cytokine storm, which greatly increases the case fatality rate. Moreover, there is no effective drug that can resist the novel coronavirus so far, so it’s urgent to develop antiviral drug for the SARS-CoV-2. In our research, we screened 29 compounds with a score lower than -6 from 35 flavonoid compounds by molecular docking. (-)-Gallocatechin gallate, (+)-Gallocatechin and Baicalein were identified to have potent inhibit activity with IC50 5.774±0.805μM, 13.14±2.081μM and 5.158±0.928μM by FRET assay. Subsequently, we conducted molecular docking experiments, which showed that (-)-Gallocatechin gallate, (+)-Gallocatechin and Baicalein were non-covalently bound to Mpro through π-π stacking and hydrogen bonds in the Cys145 catalytic site. We further evaluated the effect of (-)-Gallocatechin gallate and Baicalein on cytokine storm use a mouse model of sepsis. (-)-Gallocatechin gallate and Baicalein significant reduced sepsis severity based on weight, murine sepsis score and survival rate and reduced the inflammatory factors level such as TNF-α, IL-1α, IL-4 and IL-10.  Overall, (-)-Gallocatechin gallate and Baicalein may be potential drugs for symptomatic treatment of COVID-19.

The safety and efficacy of mesenchymal stem cells in the treatment of COVID-19-associated pneumonia: a systematic review and meta-analysis (preprint)

Mesenchymal stem cells (MSCs) therapy is considered one of the most promising treatments in the context of the coronavirus disease 2019 (COVID-19) pandemic. However, the safety and effectiveness of MSCs in the treatment of COVID-19-associated pneumonia patients need to be systematically reviewed and analyzed. Two independent researchers searched for the relevant studies published between October 2019 and April 2021 in PubMed, Embase, Cochrane Library, WAN FANG, and CNKI databases. A total of 22 studies involving 371 patients were included in the present study. MSCs were administered in 247 participants, and MSCs were allogeneic from umbilical cord, adipose tissue, menstrual blood, placenta, Whartons jelly, or unreported sources. Combined results found that MSCs group significantly reduced the incidence of adverse events (OR = 0.43, 95%CI. = 0.22[~]0.84, P = 0.01) and mortality (OR = 0.17, 95%CI. = 0.06[~]0.49, P < 0.01), and the difference compared with control group was statistically significant. No MSCs treat-related serious adverse events were reported. The lung function and radiographic outcomes, and biomarker levels of inflammation and immunity all showed improvement trends. Therefore, MSCs therapy is an effective and safe method in the treatment of COVID-19-associated pneumonia and shows advantages in less adverse events and mortality. However, a standard and effective MSCs treatment program needs to be developed.

Thoughts on Online Teaching of Employment Guidance Course for Civil Aviation Majors under the COVID-19 Epidemic--Based on the teaching practice of college students enrolled in 2018 in the Civil Aviation Management Institute of China

The employment situation in civil aviation has become more severe this year due to the adverse effects of the COVID-19 epidemic. The online teaching of employment guidance courses can promote high-quality employment for graduates, but also poses new challenges for teachers and students. For college students enrolled in 2018 majoring in civil aviation, the teachers in the Civil Aviation Management Institute of China accomplished the employment guidance course, adopting a teaching method combining online teaching with offline guidance, and applying the Deming cycle to continuously improve the course quality. To facilitate better employment of civil aviation graduates under the epidemic, this paper suggests that it is necessary to establish an employment guidance and service system, improve the comprehensive quality of graduates, promote cooperation and mutual assistance between schools and employers, and guide graduates to start their businesses or further study rationally.

The Blood-Brain Barrier is Dysregulated in COVID-19 and Serves as a CNS Entry Route for SARS-CoV-2 (preprint)

Neurological complications are common in COVID-19 patients. Although severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been detected in patients’ brain tissues, its entry routes and resulting consequences are not well understood. Here, we report that the blood-brain barrier (BBB) and its microenvironment show pronounced upregulation of interferon signaling pathways in fatal COVID-19. Moreover, human induced pluripotent stem cell (hiPSC)-derived brain capillary endothelial-like cells (BCECs) were susceptible to SARS-CoV-2 infection and recapitulated the transcriptional changes detected in vivo . While BCECs were not compromised in their paracellular tightness, we found SARS-CoV-2 in the basolateral compartment in transwell assays after apical infection, suggesting active transcytosis of the virus across the BBB in vitro . SARS-CoV-2 entry into BCECs could be reduced by anti-spike-, anti-ACE2- and anti-NRP1-specific antibodies or the TMPRSS2 inhibitor nafamostat. Together, our data provide direct evidence for SARS-CoV-2 brain entry across the BBB resulting in an increase in interferon signaling.

LazySampling and LinearSampling: Fast Stochastic Sampling of RNA Secondary Structure with Applications to SARS-CoV-2 (preprint)

Many RNAs fold into multiple structures at equilibrium. The classical stochastic sampling algorithm can sample secondary structures according to their probabilities in the Boltzmann ensemble, and is widely used. However, this algorithm, consisting of a bottom-up partition function phase followed by a top-down sampling phase, suffers from three limitations: (a) the formulation and implementation of the sampling phase are unnecessarily complicated; (b) the sampling phase repeatedly recalculates many redundant recursions already done during the partition function phase; (c) the partition function runtime scales cubically with the sequence length. These issues prevent stochastic sampling from being used for very long RNAs such as the full genomes of SARS-CoV-2. To address these problems, we first adopt a hypergraph framework under which the sampling algorithm can be greatly simplified. We then present three sampling algorithms under this framework, among which the LazySampling algorithm is the fastest by eliminating redundant work in the sampling phase via on-demand caching. Based on LazySampling, we further replace the cubic-time partition function by a linear-time approximate one, and derive LinearSampling, an end-to-end linear-time sampling algorithm that is orders of magnitude faster than the standard one. For instance, LinearSampling is 176× faster (38.9s vs. 1.9h) than Vienna RNAsubopt on the full genome of Ebola virus (18,959 nt ). More importantly, LinearSampling is the first RNA structure sampling algorithm to scale up to the full-genome of SARS-CoV-2 without local window constraints, taking only 69.2 seconds on its reference sequence (29,903 nt ). The resulting sample correlates well with the experimentally-guided structures. On the SARS-CoV-2 genome, LinearSampling finds 23 regions of 15 nt with high accessibilities, which are potential targets for COVID-19 diagnostics and drug design. See code: https://github.com/LinearFold/LinearSampling

Epidemiological feature, viral shedding, and antibody seroconversion among asymptomatic SARS-CoV-2 carriers and symptomatic/presymptomatic COVID-19 patients (preprint)

Summary Novel coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is pandemic. However, data concerning the epidemiological features, viral shedding, and antibody dynamics between asymptomatic SARS-CoV-2 carriers and COVID-19 patients remain controversial. We enrolled 193 subjects infected with SARS-CoV-2 in Ningbo and Zhoushan, Zhejiang, China from January 21 to March 6, 2020. All subjects were followed up to monitor the dynamics of immunoglobulin M (IgM) and IgG against SARS-CoV-2. Of those, 31 were asymptomatic carriers, 149 were symptomatic patients, and 14 were presymptomatic patients. Compared to symptomatic patients, asymptomatic carriers were younger and had higher levels of white blood cell and lymphocyte, lower levels of C-reactive protein and viral load, and shorter viral shedding duration. Conversion of IgM from positive to negative was shorter in asymptomatic carriers than in COVID-19 patients ( P =0.030). The proportion of those persistently seropositive for IgG was higher in COVID-19 patients than in asymptomatic carriers ( P =0.037). Viral load was higher in symptomatic than presymptomatic patients. Viral shedding was longer in presymptomatic patients than in asymptomatic carriers. Conclusively, asymptomatic carriers have a higher antiviral immunity to clear SARS-CoV-2 than do symptomatic patients and this antiviral immunity is not contributable to humoral immunity.

Sterilizing immunity against SARS-CoV-2 in hamsters conferred by a novel recombinant subunit vaccine (preprint)

A safe and effective SARS-CoV-2 vaccine is essential to avert the on-going COVID-19 pandemic. Here, we developed a subunit vaccine, which is comprised of CHO-expressed spike ectodomain protein (StriFK) and nitrogen bisphosphonates-modified zinc-aluminum hybrid adjuvant (FH002C). This vaccine candidate rapidly elicited the robust humoral response, Th1/Th2 balanced helper CD4 T cell and CD8 T cell immune response in animal models. In mice, hamsters, and non-human primates, 2-shot and 3-shot immunization of StriFK-FH002C generated 28- to 38-fold and 47- to 269-fold higher neutralizing antibody titers than the human COVID-19 convalescent plasmas, respectively. More importantly, the StriFK-FH002C immunization conferred sterilizing immunity to prevent SARS-CoV-2 infection and transmission, which also protected animals from virus-induced weight loss, COVID-19-like symptoms, and pneumonia in hamsters. Vaccine-induced neutralizing and cell-based receptor-blocking antibody titers correlated well with protective efficacy in hamsters, suggesting vaccine-elicited protection is immune-associated. The StriFK-FH002C provided a promising SARS-CoV-2 vaccine candidate for further clinical evaluation.