Identification of key mutations responsible for the enhancement of receptor-binding affinity and immune escape of SARS-CoV-2 Omicron variant.

The Omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has raised concerns worldwide due to its enhanced transmissibility and immune escapability. The first dominant Omicron BA.1 subvariant harbors more than 30 mutations in the spike protein from the prototype virus, of which 15 mutations are located at the receptor binding domain (RBD). These mutations in the RBD region attracted significant attention, which potentially enhance the binding of the receptor human angiotensin-converting enzyme 2 (hACE2) and decrease the potency of neutralizing antibodies/nanobodies. This study applied the molecular dynamics simulations combined with the molecular mechanics-generalized Born surface area (MMGBSA) method, to investigate the molecular mechanism behind the impact of the mutations acquired by Omicron on the binding affinity between RBD and hACE2. Our results indicate that five key mutations, i.e., N440K, T478K, E484A, Q493R, and G496S, contributed significantly to the enhancement of the binding affinity by increasing the electrostatic interactions of the RBD-hACE2 complex. Moreover, fourteen neutralizing antibodies/nanobodies complexed with RBD were used to explore the effects of the mutations in Omicron RBD on their binding affinities. The calculation results indicate that the key mutations E484A and Y505H reduce the binding affinities to RBD for most of the studied neutralizing antibodies/nanobodies, mainly attributed to the elimination of the original favorable gas-phase electrostatic and hydrophobic interactions between them, respectively. Our results provide valuable information for developing effective vaccines and antibody/nanobody drugs.

Impact of the COVID-19 pandemic on the hospital attendance of patients with primary cervical cancer in Heilongjiang, China.

Information regarding the impact of the coronavirus disease 2019 (COVID-19) pandemic on cervical cancer in mainland China is lacking. We explored its impact on the hospital attendance of patients with primary cervical cancer. We included 1918 patients with primary cervical cancer who initially attended Harbin Medical University Cancer Hospital between January 23, 2019, and January 23, 2021. Attendance decreased by 31%, from 1135 in 2019 to 783 in 2020, mainly from January to June (𝜒2 = 73.362, P < .001). The percentage of patients detected by screening decreased from 12.1% in January-June 2019 to 5.8% in January-June 2020 (𝜒2 = 7.187, P = .007). Patients with stage I accounted for 28.4% in 2020 significantly lower than 36.6% in 2019 (𝜒2 = 14.085, P < .001), and patients with stage III accounted for 27.1% in 2020 significantly higher than 20.5% in 2019 (𝜒2 = 11.145, P < .001). Waiting time for treatment was extended from 8 days (median) in January-June and July-December 2019 to 16 days in January-June (𝜒2 = 74.674, P < .001) and 12 days in July-December 2020 (𝜒2 = 37.916, P < .001). Of the 179 patients who delayed treatment, 164 (91.6%) were for the reasons of the healthcare providers. Compared to 2019, the number of patients in Harbin or non-Harbin in Heilongjiang Province and outside the province decreased, and cross-regional medical treatment has been hindered. The COVID-19 pandemic has negatively impacted cervical cancer patient attendance at the initial phase. These results are solid evidence that a strategy and mechanism for the effective attendance of cervical cancer patients in response to public health emergencies is urgently needed.

Exposure to negative foreign COVID-19 news predicts lower support for immigration policy in China.

We present a framework for studying the spillover effect of negative foreign COVID-19 news on attitudes towards immigration. Our framework proposes that exposure to negative COVID-19 news from foreign countries can activate negative associations with foreigners, reduce positive attitudes towards them, and increase perceived threat, ultimately leading to decreased support for immigration. We conducted three studies to test this framework. Study 1 found that exposure to negative COVID-19 news about a foreign country increased negative valence associations with that country. Study 2 showed that exposure to more negative COVID-19 news about foreign countries was associated with lower acceptance of immigration policies in real life. Study 3 replicated the spillover effect of negative news exposure using a scenario manipulation. The effects of negative news exposure on immigration policy acceptance in both Studies 2 and 3 were mediated by changes in foreigner attitudes and intergroup threat. Our results demonstrate the important spillover effect of negative foreign COVID-19 news exposure on immigration attitudes and highlight the association perspective as a foundation for understanding attitude changes during the COVID-19 pandemic.

Ferroptosis and multi-organ complications in COVID-19: mechanisms and potential therapies.

COVID-19 is an infectious disease caused by SARS-CoV-2, with respiratory symptoms as primary manifestations. It can progress to severe illness, leading to respiratory failure and multiple organ dysfunction. Recovered patients may experience persistent neurological, respiratory, or cardiovascular symptoms. Mitigating the multi-organ complications of COVID-19 has been highlighted as a crucial part of fighting the epidemic. Ferroptosis is a type of cell death linked to altered iron metabolism, glutathione depletion, glutathione peroxidase 4 (GPX4) inactivation, and increased oxidative stress. Cell death can prevent virus replication, but uncontrolled cell death can also harm the body. COVID-19 patients with multi-organ complications often exhibit factors related to ferroptosis, suggesting a possible connection. Ferroptosis inhibitors can resist SARS-CoV-2 infection from damaging vital organs and potentially reduce COVID-19 complications. In this paper, we outline the molecular mechanisms of ferroptosis and, based on this, discuss multi-organ complications in COVID-19, then explore the potential of ferroptosis inhibitors as a supplementary intervention for COVID-19. This paper will provide a reference for the possible treatment of SARS-CoV-2 infected disease to reduce the severity of COVID-19 and its subsequent impact.

Prevalence and risk factors of post-traumatic stress disorder symptoms among Chinese health care workers following the COVID-19 pandemic

In December 2019, coronavirus disease 2019 (COVID-19) appeared in Wuhan (Hubei, China) and subsequently swept the globe. In addition to the risk of infection, there is a strong possibility that post-traumatic stress disorder (PTSD) may be a secondary effect of the pandemic. Health care workers (HCWs) participating in the pandemic are highly exposed to and may bear the brunt out of stressful or traumatic events. In this cross-sectional study, we assessed the morbidity and risk factors of PTSD symptoms among Chinese HCWs. A total of 457 HCWs were recruited from March 15, 2020, to Mach 22, 2020, including HCWs in Wuhan and Hubei Province (excluding Wuhan), the areas first and most seriously impacted by COVID-19. The morbidity of PTSD symptoms was assessed by the Event Scale–Revised (IES-R). The risk factors for PTSD symptoms were explored by means of logistic regression analysis. Over 40% of the respondents experienced PTSD symptoms more than one month after the COVID-19 outbreak, and this proportion increased to 57.7% in Wuhan HCWs, especially females and HCWs on the frontline. Thus, rapid mental health assessment and effective psychological interventions need to be developed for frontline HCWs to prevent long-term PTSD-related disabilities. Moreover, Negative coping style and neuroticism personality may be regarded as high risk factors for PTSD symptoms. Improving individual coping strategies to enhance resilience should be the focus of further preventive intervention strategies.

Prevention and Control of COVID-19 Infection and Property Management: Evidence from Wuhan, China

Property enterprise has contributed significantly to the prevention and control of COVID-19, and its functions received positive feedback from the urban residents via a survey. Detailed data on confirmed COVID-19 cases in 446 communities in Wuhan were collected and the property fee of each community was used to assess the quality of the property services provided. Both binary logit and ordered logit models were used to measure the impact of property fees on the pandemic prevention and control efficiency of each community. The results showed that a higher property fee corresponded to a better property service and a higher probability that the residential community would be free of COVID-19. Furthermore, where property fees were higher, pandemic prevention and control efficiency increased and the community achieved a lower pandemic risk level. In conclusion, the promotion of high-quality property services is conducive to community disease prevention and control in the case of a pandemic.

Study of the Effects of Several SARS-CoV-2 Structural Proteins on Antiviral Immunity.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Spike (S) protein is a critical viral antigenic protein that enables the production of neutralizing antibodies, while other structural proteins, including the membrane (M), nucleocapsid (N) and envelope (E) proteins, have unclear roles in antiviral immunity. In this study, S1, S2, M, N and E proteins were expressed in 16HBE cells to explore the characteristics of the resultant innate immune response. Furthermore, peripheral blood mononuclear cells (PBMCs) from mice immunized with two doses of inactivated SARS-CoV-2 vaccine or two doses of mRNA vaccine were isolated and stimulated by these five proteins to evaluate the corresponding specific T-cell immune response. In addition, the levels of humoral immunity induced by two-dose inactivated vaccine priming followed by mRNA vaccine boosting, two homologous inactivated vaccine doses and two homologous mRNA vaccine doses in immunized mice were compared. Our results suggested that viral structural proteins can activate the innate immune response and elicit a specific T-cell response in mice immunized with the inactivated vaccine. However, the existence of the specific T-cell response against M, N and E is seemingly insufficient to improve the level of humoral immunity.

Divalent siRNAs are bioavailable in the lung and efficiently block SARS-CoV-2 infection.

The continuous evolution of SARS-CoV-2 variants complicates efforts to combat the ongoing pandemic, underscoring the need for a dynamic platform for the rapid development of pan-viral variant therapeutics. Oligonucleotide therapeutics are enhancing the treatment of numerous diseases with unprecedented potency, duration of effect, and safety. Through the systematic screening of hundreds of oligonucleotide sequences, we identified fully chemically stabilized siRNAs and ASOs that target regions of the SARS-CoV-2 genome conserved in all variants of concern, including delta and omicron. We successively evaluated candidates in cellular reporter assays, followed by viral inhibition in cell culture, with eventual testing of leads for in vivo antiviral activity in the lung. Previous attempts to deliver therapeutic oligonucleotides to the lung have met with only modest success. Here, we report the development of a platform for identifying and generating potent, chemically modified multimeric siRNAs bioavailable in the lung after local intranasal and intratracheal delivery. The optimized divalent siRNAs showed robust antiviral activity in human cells and mouse models of SARS-CoV-2 infection and represent a new paradigm for antiviral therapeutic development for current and future pandemics.

Effects of Resveratrol on Pulmonary Fibrosis via TGF-ß/Smad/ERK Signaling Pathway.

Pulmonary fibrosis (PF) is a progressive pulmonary disease with no effective treatment and high mortality. Resveratrol has shown promising benefits in the treatment of PF. However, the probable efficacy and underlying mechanism of resveratrol in PF treatment remain unclear. This study investigates the intervention effects and potential mechanisms underpinning the treatment of PF with resveratrol. The histopathological analysis of lung tissues in PF rats showed that resveratrol improved collagen deposition and reduced inflammation. Resveratrol decreased the levels of collagen, glutathione, superoxide dismutase, myeloperoxidase, and hydroxyproline, lowered total anti-oxidant capacity, and suppressed the migration of TGF-[Formula: see text]1 and LPS-induced 3T6 fibroblasts. With resveratrol intervention, the protein and RNA expressions of TGF-[Formula: see text]1, a-SMA, Smad3/4, p-Smad3/4, CTGF, and p-ERK1/2 were markedly downregulated. Similarly, the protein and RNA expression levels of Col-1 and Col-3 were significantly downregulated. However, Smad7 and ERK1/2 were evidently upregulated. The protein and mRNA expression levels of TGF-[Formula: see text], Smad, and p-ERK correlated positively with the lung index, while the protein and mRNA expression levels of ERK correlated negatively with the lung index. These results reveal that resveratrol may have therapeutic effects on PF by reducing collagen deposition, oxidation, and inflammation. The mechanism is associated with the regulation of the TGF-[Formula: see text]/Smad/ERK signaling pathway.

Microfluidics for COVID-19: From Current Work to Future Perspective.

Spread of coronavirus disease 2019 (COVID-19) has significantly impacted the public health and economic sectors. It is urgently necessary to develop rapid, convenient, and cost-effective point-of-care testing (POCT) technologies for the early diagnosis and control of the plague's transmission. Developing POCT methods and related devices is critical for achieving point-of-care diagnosis. With the advantages of miniaturization, high throughput, small sample requirements, and low actual consumption, microfluidics is an essential technology for the development of POCT devices. In this review, according to the different driving forces of the fluid, we introduce the common POCT devices based on microfluidic technology on the market, including paper-based microfluidic, centrifugal microfluidic, optical fluid, and digital microfluidic platforms. Furthermore, various microfluidic-based assays for diagnosing COVID-19 are summarized, including immunoassays, such as ELISA, and molecular assays, such as PCR. Finally, the challenges of and future perspectives on microfluidic device design and development are presented. The ultimate goals of this paper are to provide new insights and directions for the development of microfluidic diagnostics while expecting to contribute to the control of COVID-19.

An approach combining deep learning and molecule docking for drug discovery of cathepsin L.

OBJECTIVES: Cathepsin L (CTSL) is a promising therapeutic target for metabolic disorders and COVID-19. However, there are still no clinically available CTSL inhibitors. Our objective is to develop an approach for the discovery of potential reversible covalent CTSL inhibitors. METHODS: The authors combined Chemprop, a deep learning-based strategy, and the Schrödinger CovDock algorithm to identify potential CTSL inhibitors. First, they used Chemprop to train a deep learning model capable of predicting whether a molecule would inhibit the activity of CTSL and performed predictions on ZINC20 in-stock librarie (~9.2 million molecules). Then, they selected the top-200 predicted molecules and performed the Schrödinger covalent docking algorithm to explore the binding patterns to CTSL (PDB: 5MQY). The authors then calculated the binding energies using Prime MM/GBSA and examined the stability between the best two molecules and CTSL using 100ns molecular dynamics simulations. RESULTS: The authors found five molecules that showed better docking results than the well-known cathepsin inhibitor odanacatib. Notably, two of these molecules, ZINC-35287427 and ZINC-1857528743, showed better docking results with CTSL compared to other cathepsins. CONCLUSION: Our approach enables drug discovery from large-scale databases with little computational consumption, which will save the cost and time required for drug discovery.

Prevalence and risk factors of post-traumatic stress disorder symptoms among Chinese health care workers following the COVID-19 pandemic.

In December 2019, coronavirus disease 2019 (COVID-19) appeared in Wuhan (Hubei, China) and subsequently swept the globe. In addition to the risk of infection, there is a strong possibility that post-traumatic stress disorder (PTSD) may be a secondary effect of the pandemic. Health care workers (HCWs) participating in the pandemic are highly exposed to and may bear the brunt out of stressful or traumatic events. In this cross-sectional study, we assessed the morbidity and risk factors of PTSD symptoms among Chinese HCWs. A total of 457 HCWs were recruited from March 15, 2020, to Mach 22, 2020, including HCWs in Wuhan and Hubei Province (excluding Wuhan), the areas first and most seriously impacted by COVID-19. The morbidity of PTSD symptoms was assessed by the Event Scale-Revised (IES-R). The risk factors for PTSD symptoms were explored by means of logistic regression analysis. Over 40% of the respondents experienced PTSD symptoms more than one month after the COVID-19 outbreak, and this proportion increased to 57.7% in Wuhan HCWs, especially females and HCWs on the frontline. Thus, rapid mental health assessment and effective psychological interventions need to be developed for frontline HCWs to prevent long-term PTSD-related disabilities. Moreover, Negative coping style and neuroticism personality may be regarded as high risk factors for PTSD symptoms. Improving individual coping strategies to enhance resilience should be the focus of further preventive intervention strategies.

Multivariate models of commodity futures markets: a dynamic copula approach.

We apply flexible multivariate dynamic models to capture the dependence structure of various US commodity futures across different sectors between 2004 and 2022; particular attention is paid to the 2008 financial crisis and the COVID-19 pandemic. Our copula-based models allow for time-varying nonlinear and asymmetric dependence by integrating elliptical and skewed copulas with dynamic conditional correlation (DCC) and block dynamic equicorrelation (Block DECO). Flexible copula models that allow for multivariate asymmetry and tail dependence are found to provide the best performance in characterizing co-movements of commodity returns. We also find that the connectedness between commodities has dramatically increased during the financial distress and the COVID-19 pandemic. The impacts of the financial crisis appear to be more persistent than those of the pandemic. We apply our models to some risk management tasks in the commodity markets. Our results suggest that optimal portfolio weights based on dynamic copulas have persistently outperformed the equal-weighted portfolio, demonstrating the practicality and usefulness of our proposed models.

Genome-Wide Characterization of SARS-CoV-2 Cytopathogenic Proteins in the Search of Antiviral Targets.

Therapeutic inhibition of critical viral functions is important for curtailing coronavirus disease 2019 (COVID-19). We sought to identify antiviral targets through the genome-wide characterization of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) proteins that are crucial for viral pathogenesis and that cause harmful cytopathogenic effects. All 29 viral proteins were tested in a fission yeast cell-based system using inducible gene expression. Twelve proteins, including eight nonstructural proteins (NSP1, NSP3, NSP4, NSP5, NSP6, NSP13, NSP14, and NSP15) and four accessory proteins (ORF3a, ORF6, ORF7a, and ORF7b), were identified that altered cellular proliferation and integrity and induced cell death. Cell death correlated with the activation of cellular oxidative stress. Of the 12 proteins, ORF3a was chosen for further study in mammalian cells because it plays an important role in viral pathogenesis and its activities are linked to lung tissue damage and a cytokine storm. In human pulmonary and kidney epithelial cells, ORF3a induced cellular oxidative stress associated with apoptosis and necrosis and caused activation of proinflammatory response with production of the cytokines tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), and IFN-ß1, possibly through the activation of nuclear factor kappa B (NF-κB). To further characterize the mechanism, we tested a natural ORF3a Beta variant, Q57H, and a mutant with deletion of the highly conserved residue, ΔG188. Compared with wild-type ORF3a, the ΔG188 variant yielded more robust activation of cellular oxidative stress, cell death, and innate immune response. Since cellular oxidative stress and inflammation contribute to cell death and tissue damage linked to the severity of COVID-19, our findings suggest that ORF3a is a promising, novel therapeutic target against COVID-19. IMPORTANCE The ongoing COVID-19 pandemic caused by SARS-CoV-2 has claimed over 5.5 million lives with more than 300 million people infected worldwide. While vaccines are effective, the emergence of new viral variants could jeopardize vaccine protection. Treatment of COVID-19 by antiviral drugs provides an alternative to battle against the disease. The goal of this study was to identify viral therapeutic targets that can be used in antiviral drug discovery. Utilizing a genome-wide functional analysis in a fission yeast cell-based system, we identified 12 viral candidates, including ORF3a, which cause cellular oxidative stress, inflammation, apoptosis, and necrosis that contribute to cytopathogenicity and COVID-19. Our findings indicate that antiviral agents targeting ORF3a could have a great impact on COVID-19.

Posttraumatic stress disorder symptoms among Chinese college students following the COVID-19 outbreak.

Objective: This study examined the prevalence of posttraumatic stress disorder (PTSD) symptoms in college students 1 month after the lockdown of Wuhan to identify possible risk factors for PTSD symptoms in a cross-sectional study. Methods: Out of 10,502 who responded, 9,274 students impacted by the COVID-19 pandemic were included in our study. PTSD symptoms was evaluated by the Impact of Event Scale-revised (IES-R). Anxiety/depression symptoms were evaluated by the Kessler Psychological Distress Scale (K10). Personality traits, coping style, and social support were assessed by the Eysenck Personality Questionnaire-Revised Short Scale for Chinese (EPQ-RSC), the Simplified Coping Style Questionnaire (SCSQ), and the Social Support Rating Scale (SSRS). Logistic regression analysis was utilized to further explore risk factors for PTSD symptoms. Results: More than 1 month after the COVID-19 outbreak, 13.1% of college students developed PTSD symptoms, indicating that COVID-19 associated stressful experiences were connected with PTSD symptoms. After the COVID-19 outbreak, subjects with symptomatologic PTSD symptoms were more likely to experience strained relationships with their family, to have close contact with COVID-19 patients and to drop out of college. The logistic regression model demonstrated the association factors of PTSD symptoms. Neuroticism, psychoticism and an avoidant coping style were associated with increased risk for PTSD symptoms, while an active coping style was protective against PTSD symptoms during this pandemic. Conclusion: The results showed that PTSD symptoms was prevalent in Chinese college students 1 month after the COVID-19 outbreak. Effective psychological support work should be carried out accordingly.

Impact of Social Support on Depressive Symptoms among Postgraduates during the Coronavirus Disease 2019 Pandemic: A Moderated Mediation Analysis.

The coronavirus disease (COVID-19) pandemic continues to spread worldwide, and its related stressors are causing a high prevalence of mental health problems among graduate students. This has the potential for long-term effects on their mental well-being. However, few large-scale studies have been conducted on multiple risk and protective factors. Therefore, we aimed to test the impact of social support on depressive symptoms among graduate students and analyze the mediating role of positive coping and the regulatory role of neuroticism. From 1-8 October 2021, 1812 Chinese graduate students were surveyed online. We used a structural equation model to study the mediating role of positive coping in the relationship between social support and depressive symptoms and used the Hayes PROCESS macro to conduct mediating analysis. The incidence of depressive symptoms was 10.40%. These results showed that positive coping influenced the social support's influence on depression symptoms to some extent. Moreover, neuroticism regulates the indirect relationship between social support and depressive symptoms through active coping. Further research is needed to assess the impact of various forms of social support on graduate students' mental health and to develop strategies for maintaining their well-being, such as network mindfulness.

Trace detection of SARS-CoV-2 N-protein by diamond solution-gate field-effect transistor.

In this study, we introduced H-terminated diamond solution-gate field-effect transistor (H-diamond SGFET) to detect trace SARS-CoV-2 N-protein, which plays an important role in replication and transcription of viral RNA. 1-Pyrenebutyric acid-N-hydroxy succinimide ester (Pyr-NHS) was modified on H-diamond surface as linker, on which the specific antibody of SARS-CoV-2 N-protein was catenated. Fourier transform infrared spectrum, scanning electron microscope and energy dispersive spectrum were utilized to demonstrate the modification of H-diamond with Pyr-NHS and antibody. Shifts of IDS(max) at VGS = -500 mV in transfer characteristics of H-diamond SGFET was observed to determine N-protein concentration in phosphate buffer solution. Good linear relationship between IDS(max) and log10(N-protein) was observed from 10-14 to 10-5 g/mL with goodness of fit R2 = 0.90 and sensitivity of 1.98 µA/Log10 [concentration of N-protein] at VDS = -500 mV, VGS = -500 mV. Consequently, this prepared H-diamond SGFET biosensor may provide a new idea for diagnosis of SARS-CoV-2 due to a wide detection range from 10-14 to 10-5 g/mL and low limit of detection 10-14 g/mL.

Expression of angiotensin converting enzyme 2 mRNA in different SARS-CoV-2 infection states and times.

To measure the expression of angiotensin converting enzyme 2 (ACE2) mRNA in SARS-CoV-2 infection with different infection status and at different stages during infection, we used RT-qP CR to measure the expression of ACE2 mRNA. Measurements were analyzed by two-way repeated measures analysis of variance (RMANOVA). Expression of ACE2 mRNA was downregulated in initial stages of SARS-CoV-2 infection both in the asymptomatic infection (ASY) group and the confirmed cases (CON) group (t=-8.0845, P < 0.0001; t=-8.1904, P < 0.0001, respectively). The expression of ACE2 mRNA in the incubation period of CON group was lower compared with the intinal period of ASY group (F = 6.084, p = 0.016, partialη2 = 0.070). Relative expression of ACE2 mRNA was upregulated at the late stage of SARS-CoV-2 infection in the ASY and CON groups (F = 23.489, p = 0.000, partialη2 = 0.225; F = 46.555, p = 0.000, partialη2 = 0.365, respectively). The relative expression of ACE2 mRNA was down-regulated (mean ± SEM:0.69 ± 0.03) after inoculation with SARSCoV- 2 Spike pseudovirus, and there was a statistical difference (one-way t test, mean diffience =-0.31, 95%CI: -0.37˜-0.24, t=-8.1904, P < 0.0001). The expression of ACE2 mRNA is downregulated in the initial stage of SARS-CoV-2 infection, and then upregulated in the late stage of SARS-CoV-2 infection. The lower expression of ACE2 mRNA during the incubation period can lead to clinical symptoms. Downregulation of ACE2 mRNA was related to the interaction between SARS-CoV-2 S protein and ACE2.Communicated by Ramaswamy H. Sarma.

The roles of risk perception, negative emotions and perceived efficacy in the association between COVID-19 infection cues and preventive behaviors: a moderated mediation model.

Preventive behaviors during the COVID-19 pandemic are especially critical to the protection of individuals whose family members or acquaintances have been infected. However, limited research has explored the influence of infection cues on preventive behaviors. This study proposed an interaction model of environment-cognitive/affective-behavior to elucidate the mechanism by which infection cues influence preventive behaviors and the roles of risk perception, negative emotions, and perceived efficacy in that influence. To explore the relationships among these factors, we conducted a cross-sectional online survey in 34 provinces in China during the first wave of the COVID-19 pandemic. A total of 26,511 participants responded to the survey, and 20,205 valid responses (76.2%) were obtained for further analysis. The moderated mediation results show that infection cues positively predicted preventive behaviors in a manner mediated by risk perception and negative emotions. Moreover, perceived efficacy moderated the influence of infection cues not only on preventive behaviors but also on risk perception and negative emotions. The higher the perceived efficacy, the stronger these influences were. These findings validated our model, which elucidates the mechanisms underlying the promoting effect of infection cues on preventive behaviors during the initial stage of the COVID-19 pandemic. The implications of these results for the COVID-19 pandemic and beyond are discussed.

School and community reopening during the COVID-19 pandemic: a mathematical modelling study.

Operating schools safely during the COVID-19 pandemic requires a balance between health risks and the need for in-person learning. Using demographic and epidemiological data between 31 July and 23 November 2020 from Toronto, Canada, we developed a compartmental transmission model with age, household and setting structure to study the impact of schools reopening in September 2020. The model simulates transmission in the home, community and schools, accounting for differences in infectiousness between adults and children, and accounting for work-from-home and virtual learning. While we found a slight increase in infections among adults (2.2%) and children (4.5%) within the first eight weeks of school reopening, transmission in schools was not the key driver of the virus resurgence in autumn 2020. Rather, it was community spread that determined the outbreak trajectory, primarily due to increases in contact rates among adults in the community after school reopening. Analyses of cross-infection among households, communities and schools revealed that home transmission is crucial for epidemic progression and safely operating schools, while the degree of in-person attendance has a larger impact than other control measures in schools. This study suggests that safe school reopening requires the strict maintenance of public health measures in the community.