Search

The pandemic caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has had a profound impact on the global health and economy. While mass vaccination for herd immunity is effective, emerging SARS-CoV-2 variants can evade spike protein-based COVID-19 vaccines. In this study, we develop a new immunization strategy by utilizing a nanocarrier, dendritic mesoporous silica nanoparticle (DMSN), to deliver the receptor-binding domain (RBD) and conserved T-cell epitope peptides (DMSN-P-R), aiming to activate both humoral and cellular immune responses in the host. The synthesized DMSN had good uniformity and dispersion and showed a strong ability to load the RBD and peptide antigens, enhancing their uptake by antigen-presenting cells (APCs) and promoting antigen delivery to lymph nodes. The DMSN-P-R vaccine elicited potent humoral immunity, characterized by highly specific RBD antibodies. Neutralization tests demonstrated significant antibody-mediated neutralizing activity against live SARS-CoV-2. Crucially, the DMSN-P-R vaccine also induced robust T-cell responses that were specifically stimulated by the RBD and conserved T-cell epitope peptides of SARS-CoV-2. The DMSN demonstrated excellent biocompatibility and biosafety in vitro and in vivo, along with degradability. Our study introduces a promising vaccine strategy that utilizes nanocarriers to deliver a range of antigens, effectively enhancing both humoral and cellular immune responses to prevent virus transmission., (© 2023. The Author(s).)

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is characterized by a strong production of inflammatory cytokines such as TNF and IL-6, which underlie the severity of the disease. However, the molecular mechanisms responsible for such a strong immune response remains unclear. Here, utilizing targeted tandem mass spectrometry to analyze serum metabolome and lipidome in COVID-19 patients at different temporal stages, we identified that 611 metabolites (of 1,039) were significantly altered in COVID-19 patients. Among them, two metabolites, agmatine and putrescine, were prominently elevated in the serum of patients; and 2-quinolinecarboxylate was changed in a biphasic manner, elevated during early COVID-19 infection but levelled off. When tested in mouse embryonic fibroblasts (MEFs) and macrophages, these 3 metabolites were found to activate the NF-κB pathway that plays a pivotal role in governing cytokine production. Importantly, these metabolites were each able to cause strong increase of TNF and IL-6 levels when administered to wildtype mice, but not in the mice lacking NF-κB. Intriguingly, these metabolites have little effects on the activation of interferon regulatory factors (IRFs) for the production of type I interferons (IFNs) for antiviral defenses. These data suggest that circulating metabolites resulting from COVID-19 infection may act as effectors to elicit the peculiar systemic inflammatory responses, exhibiting severely strong proinflammatory cytokine production with limited induction of the interferons. Our study may provide a rationale for development of drugs to alleviate inflammation in COVID-19 patients., (© 2022. Science China Press and Springer-Verlag GmbH Germany, part of Springer Nature.)

Apolipoprotein E (APOE) plays a pivotal role in lipid including cholesterol metabolism. The APOE ε4 (APOE4) allele is a major genetic risk factor for Alzheimer's and cardiovascular diseases. Although APOE has recently been associated with increased susceptibility to infections of several viruses, whether and how APOE and its isoforms affect SARS-CoV-2 infection remains unclear. Here, we show that serum concentrations of APOE correlate inversely with levels of cytokine/chemokine in 73 COVID-19 patients. Utilizing multiple protein interaction assays, we demonstrate that APOE3 and APOE4 interact with the SARS-CoV-2 receptor ACE2; and APOE/ACE2 interactions require zinc metallopeptidase domain of ACE2, a key docking site for SARS-CoV-2 Spike protein. In addition, immuno-imaging assays using confocal, super-resolution, and transmission electron microscopies reveal that both APOE3 and APOE4 reduce ACE2/Spike-mediated viral entry into cells. Interestingly, while having a comparable binding affinity to ACE2, APOE4 inhibits viral entry to a lesser extent compared to APOE3, which is likely due to APOE4's more compact structure and smaller spatial obstacle to compete against Spike binding to ACE2. Furthermore, APOE ε4 carriers clinically correlate with increased SARS-CoV-2 infection and elevated serum inflammatory factors in 142 COVID-19 patients assessed. Our study suggests a regulatory mechanism underlying SARS-CoV-2 infection through APOE interactions with ACE2, which may explain in part increased COVID-19 infection and disease severity in APOE ε4 carriers., (© 2022. The Author(s).)

Purpose: This study investigated the impact of coronavirus disease 2019 (COVID-19) from the perspectives of dental residents in Wuhan, the former COVID-19 epicenter of China., Methods: A survey form was sent to 424 residents in the School of Stomatology, Wuhan University (WHUSS) in September 2020. The form included 23 questions on demographics, study situation of residents during the COVID-19 outbreak, effect of COVID-19 on graduates, and status of residents who returned to clinic training., Results: A total of 361 (85%) survey forms were collected. Over 70% of respondents felt anxious during Wuhan lockdown. Most respondents continued studying (94%) mainly through free online resources (79%). The majority reported improvement in didactic knowledge (80%), but the respondents' perceptions of their clinical skills, especially those in Wuhan, did not change (41%) or worsened (40%) (p < 0.05). Most graduates (88%) reported having found jobs or continued study. Among the 209 responders who returned to clinical training, 52% felt no concern about COVID-19 infection, 89% thought they were equipped with adequate personal protective equipment (PPE), and 57% indicated that they received sufficient knowledge for preventing COVID-19 in clinic. Most respondents agreed that the way to gain the knowledge for preventing COVID-19 in clinic was training at dental school (93%)., Conclusion: Although online study has been appreciated by residents, concern about clinical skill learning in the COVID-19 hardest-hit area has arisen. Most graduates felt that the impact of COVID-19 on their immediate postgraduation career was limited. Teaching about infection control in dental schools seemed effective to develop a positive attitude for residents after they returned to clinical training., (© 2021 American Dental Education Association.)

Background: The novel coronavirus SARS-CoV-2 is a newly emerging virus. The antibody response in infected patients remains largely unknown, and the clinical value of antibody testing has not been fully demonstrated., Methods: 173 patients with SARS-CoV-2 infection were enrolled. Their serial plasma samples (n = 535) collected during hospitalization were tested for total antibodies (Ab), IgM, and IgG against SARS-CoV-2. The dynamics of antibodies with disease progress were analyzed., Results: Among 173 patients, the seroconversion rates for Ab, IgM, and IgG were 93.1%, 82.7%, and 64.7%, respectively. The reason for the negative antibody findings in 12 patients might be due to the lack of blood samples at the later stage of illness. The median seroconversion times for Ab, IgM, and then IgG were days 11, 12, and 4, respectively. The presence of antibodies was <40% among patients within 1 week of onset, and rapidly increased to 100.0% (Ab), 94.3% (IgM), and 79.8% (IgG) by day 15 after onset. In contrast, RNA detectability decreased from 66.7% (58/87) in samples collected before day 7 to 45.5% (25/55) during days 15-39. Combining RNA and antibody detection significantly improved the sensitivity of pathogenic diagnosis for COVID-19 (P < .001), even in the early phase of 1 week from onset (P = .007). Moreover, a higher titer of Ab was independently associated with a worse clinical classification (P = .006)., Conclusions: Antibody detection offers vital clinical information during the course of SARS-CoV-2 infection. The findings provide strong empirical support for the routine application of serological testing in the diagnosis and management of COVID-19 patients., (© The Author(s) 2020. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

The recent outbreak of COVID-19 has infected a large number of patients, increasing the importance of adequate disinfection of the hospital environment. We conducted this study to explore environmental virus contamination and the effect of terminal disinfection in the isolation ward of patients with COVID-19. A swab kit was used to sample various surfaces in the isolation and observation wards using the smear method. The samples were immediately sent to the PCR department of the laboratory for nucleic acid detection of COVID-19. We analyzed 31 high-frequency contact sites in three isolation wards of actively sick patients, of which seven were positive (22.58%, 7/31). Positive sites included the transfer window, bed rail, buffer room door handle, toilet door handle, and toilet faucet. All 55 samples taken from the wards of cured patients and the wards after terminal disinfection were negative. Virus contamination in areas frequently touched by patients in the isolation ward was high, so the awareness of correct disinfection must be increased. Use of 1,000-2,000 mg/L chlorine-containing disinfectant in the isolation ward was effective., (Copyright © 2020 Zhang, Wang, Lin, Deng, Ye, Li, Qiu and Wang.)

Purpose: A proliferation of articles surrounding the COVID-19 pandemic is calling for new insights through review. This paper aims to bibliometrically analyze the current progress of research around hospitality and tourism to define the research directions on herd immunity and the prevention of disease under the "new normal." Design/methodology/approach: This paper analyzed 326 articles regarding COVID-19 published in SSCI hospitality, leisure and tourism journals in 2020 and 2021 by combining manual analysis and bibliometrics to reveal research topics and to gain insight into research structures. Findings: The results of this paper summarized topics related to stakeholders' mentality and behavior, responses of travel suppliers to the COVID-19 pandemic, economic impact and demand forecasting, social issues of human rights and racism and reflection on tourism and transformation of the industry. More research is called for in the future to focus on a better response to the crisis, including crisis management education and training and the improving the resilience of small- and medium-sized enterprises. Research limitations/implications: A three-dimensional consideration was proposed to promote the sustainable development of hospitality and tourism. Originality/value: In the "new normal" phase of herd immunity and disease prevention, to the best of the authors' knowledge, this is the first paper that provides an up-to-date systematic overview of the evolution of COVID-19 research in tourism and hospitality and encourages more conceptual, practical and futuristic studies. [ABSTRACT FROM AUTHOR]

Inevitably, both unblocking of the COVID-19 (UNCOV) and uncertainty in the clean heating policy (2017–2021) in winter 2022 imposed complex impacts on PM 2.5 variations. Together, the urban-rural and rural-rural disparities in these impacts remain unclear. To address this gap, we conducted a synchronous observation at urban (UA)/suburban rural (SRA)/remote rural (RRA) areas to probe PM 2.5 evolutions in the post COVID-19/clean-heating (PCOV/PCH) period for further site-specific policy implications. Similar meteorological conditions among sites benefited examining the effects of emission variations. On average, PM 2.5 presented a decline order as RRA > UA > SRA. Invoking the positive matrix factorization (PMF) results, specially, the primary emissions (PE) rebounded again after experiencing a continuous decline since the stringent emission-control polices initiated in 2013. PE contributions were up to 80.2 %–83.0 % for three points. SRA benefited most from coal-to-gas and coal combustion (CC) has become its minimum contributor (10.8 %). Concurrently, subsidy reduction and natural-gas (NG) shortage compelled biomass burning (BB) to be the largest origin (21.9 %) marked by the highest K+, Cl− and OC/EC. Regarding RRA, CC (26.5 %) and BB (19.6 %) have been the first and second largest origins despite that the coal-to-electricity policy, indicating the slowdown of policy enforcement. The highest SO 4 2−, As, Sb, Tl, OC, EC and the lowest NO 3 −/SO 4 2− further verified the dominant CC. Production recovery made industrial emissions (IE) become the largest source (26.8 %) at UA. The metal associated health risks peaked at RRA due to large impacts of CC, though the most of metals related to small-scale industries peaked at UA. This is the first work to highlight that more targeted site-specific strategies in prevention/control of dominant primary sources should be formulated in the PCOV/CH period. [Display omitted] • Examined urban-rural/rural-rural disparities in winter-PM 2.5 evolutions in the post COVID-19/clean-heating period. • Primary emissions rebounded at urban (UA)/suburban rural (SRA)/remote rural (RRA) areas. • UA, SRA, and RRA witnessed peak contributions of industrial emissions, biomass-burning, and coal-combustion, respectively. • SRA benefits most from coal-to-gas transition, RRA saw the highest PM 2.5 and health risks. [ABSTRACT FROM AUTHOR]

News coverage plays a significant role in the tourism industry. 2019 Coronavirus Disease (COVID-19) has severely affected the tourism-related businesses and has been featured in Chinese news coverage. This research studied 499 newspaper articles through automated content analysis. Nine key themes were identified, including COVID-19's impact on tourism, people's sentiment, control of tourism activities and cultural venues, the role of the hospitality industry, national command and local response, tourism disputes and solutions, corporate self-improvement strategies, government assistance, and post-crisis tourism product. This research provides insights into future investigations of the tourism crisis related to an epidemic. [ABSTRACT FROM AUTHOR]

Reopen major tourist destinations is one of the significant recovery initiatives for the tourism industry after the outbreak of crises. However, few studies have focused on management measures during the reopening of tourist destinations. In this regard, this study adopts the co-word analysis to map the topics of 273 notices of the reopened national 5A scenic areas in China. The key themes are identified including (i) prevention measures, (ii) business scope, (iii) rules for tourists and (iv) preferential measures. Moreover, the management focus varies between natural and cultural destinations. This study provides suggestions for research on epidemic-induced crisis management in tourism. [ABSTRACT FROM AUTHOR]

Social media is an important element in disaster and health crisis related communication. This research reviews 10,132 online comments related to COVID-19 through automated and manual content analysis. The key themes are identified and discussed including dynamically changed tourists' risk perception, the effects of tourism enterprises' service quality in crisis, the quarantine issues in public health, the authenticity of media coverage, and racial discrimination. This research contributes to suggestions and insights for future research in the field of epidemic-induced tourism crisis. [ABSTRACT FROM AUTHOR]

Objectives: The outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly spread globally. The laboratory diagnosis of SARS-CoV-2 infection has relied on nucleic acid testing; however, it has some limitations, such as low throughput and high rates of false negatives. Tests of higher sensitivity are needed to effectively identify infected patients. Methods: This study has developed fully automated chemiluminescent immunoassays to determine IgM and IgG antibodies to SARS-CoV-2 in human serum. The assay performance has been evaluated at 10 hospitals. Clinical specificity was evaluated by measuring 972 hospitalized patients and 586 donors of a normal population. Clinical sensitivity was assessed on 513 confirmed cases of SARS-CoV-2 by RT-PCR. Results: The assays demonstrated satisfied assay precision with coefficient of variation of less than 4.45%. Inactivation of specimen did not affect assay measurement. SARS-CoV-2 IgM showed clinical specificity of 97.33 and 99.49% for hospitalized patients and the normal population respectively, and SARS-CoV-2 IgG showed clinical specificity of 97.43 and 99.15% respectively. SARS-CoV-2 IgM showed clinical sensitivity of 82.54, 92.93, and 84.62% before 7 days, 7–14 days, and after 14 days respectively, since onset of symptoms, and SARS-CoV-2 IgG showed clinical sensitivity of 80.95, 97.98, and 99.15% respectively at the same time points above. Conclusions: We have developed fully automated immunoassays for detecting SARS-CoV-2 IgM and IgG antibodies in human serum. The assays demonstrated high clinical specificity and sensitivity, and add great value to nucleic acid testing in fighting against the global pandemic of the SARS-CoV-2 infection. [ABSTRACT FROM AUTHOR]

This paper examines the impacts of COVID-19 on Chinese nationals' tourism preferences. Employing a mixed-method research design, two rounds of nation-wide online surveys were conducted, one in February 2020 when COVID-19 cases started to peak in China and another one in June 2020 when COVID-19 was a global pandemic; both survey studies were accompanied with semi-structured in-depth interviews and altogether 37 interviews were conducted in two stages. Based on both quantitative survey data and qualitative interview data, the research identified that: 1) COVID-19 significantly reduced Chinese nationals' preferences to travel to countries with high infection numbers, and geographically faraway, administratively and culturally distant outbound destinations; 2) Chinese nationals reduced their preferences in all travel modes and most of the tourism forms, but most of them would prefer nature-based, rural, and cultural destinations after COVID-19; and 3) shortened trips in short travel distance are preferred after COVID-19. The findings offer rich insights and practical implications for governments, industry organisations, and tourism operators to formulate tourism recovery strategies toward Chinese tourists. • This study examined the impacts of COVID-19 on Chinese nationals' tourism preferences. • Two rounds of nation-wide online surveys and semi-structured in-depth interviews were employed. • The findings yielded that COVID-19 had changed Chinese people's outbound destination preferences. • Chinese nationals preferred nature-based, rural, and cultural destinations after COVID-19. • Shortened trips in short travel distance were preferred after COVID-19. [ABSTRACT FROM AUTHOR]

Given growing attention toward the effects on COVID-19 on tourism, a number of institutions have made macro-level predictions related to the disease. More micro-level research are, however, needed. This study seeks to advance the understanding of tourists' potential behavioral transformation by reviewing psychological distance and construal level theory, as well as the relationship between psychological distance and perceived risk. Multiple dimensions of psychological distance and perceived risk are summarized with respect to COVID-19. The discussion suggests that global health emergencies evoke three types of tourism pattern: from general to elaborate, from open-hearted to closed, and from radical to conservative. These categories provide a conceptual foundation for empirical research considering contextual and individual stimuli. Practically, this paper highlights strategies to reduce individuals' risk perceptions, encourage specific types of tourism, and regulate unethical consumption. The recommendations also encourage the analysis of crisis recovery and relevant market analysis by tourism professionals and marketers. • Uses the rationality of applying psychological distance and construal level theory to tourism research on COVID-19. • Investigates the mechanism between psychological distance and perceived risk. • Identifies tourists' psychological distance dimensions and perceived risks. • Summarizes the transformation of tourists' behavior patterns after the outbreak of COVID-19. • Proposes research opportunities based on the conceptual model put forth in this paper. [ABSTRACT FROM AUTHOR]

The COVID-19 pandemic caused by SARS-CoV-2 infections has led to excess deaths worldwide. Neutralizing antibodies (nAbs) against viral spike protein acquired from natural infections or vaccinations contribute to protection against new- and re-infections. Besides neutralization, antibody-mediated cellular cytotoxicity (ADCC) and phagocytosis (ADCP) are also important for viral clearance. However, due to the lack of convenient methods, the ADCC and ADCP responses elicited by viral infections or vaccinations remain to be explored. Here, we developed cell-based assays using target cells stably expressing SARS-CoV-2 spikes and Jurkat-NFAT-CD16a/CD32a effector cells for ADCC/ADCP measurements of monoclonal antibodies and human convalescent COVID-19 plasmas (HCPs). In control samples (n = 190), the specificity was 99.5% (95%CI: 98.4–100%) and 97.4% (95%CI: 95.1–99.6%) for the ADCC and ADCP assays, respectively. Among 87 COVID-19 HCPs, 83 (sensitivity: 95.4%, 95%CI: 91.0–99.8%) and 81 (sensitivity: 93.1%, 95%CI: 87.8–98.4%) showed detectable ADCC (titer range: 7.4–1721.6) and ADCP activities (titer range: 4–523.2). Notably, both ADCC and ADCP antibody titers positively correlated with the nAb titers in HCPs. In summary, we developed new tools for quantitative ADCC and ADCP analysis against SARS-CoV-2, which may facilitate further evaluations of Fc-mediated effector functions in preventing and treating against SARS-CoV-2. • ADCC and ADCP assays were established using target cells stably expressing SARS-CoV-2 spike and FcγR/NFAT-reporter cells. • Our assays provided convenient and reliable tools to evaluate ADCC and ADCP activities of antibodies and human samples. • In COVID-19 plasmas, the ADCC and ADCP antibody titers positively correlated with the neutralizing antibody levels. [ABSTRACT FROM AUTHOR]