An infectious disease model considering the impact of imported cases on internal spread of COVID-19

The coronavirus disease 2019(COVID-19) pandemic spreads across borders with the frequent global population movement. To explore the impact of the COVID-19 pandemic on China's domestic epidemic prevention and control, based on the classical infectious disease dynamics model this paper proposes an infectious disease model that considers oversea imported cases. The model can simulate three situations:national pandemic without imported cases, no domestic cases with only imported cases, and domestic cases with international travellers entering simultaneously. By calculating the peak case number and range of infection spread duration in these situations, as well as the amount of medical resources invested, the model has shown the different results of impact of entry type on the domestic pandemic and different pressures on medical resources. Finally, the paper suggests that testing measures should be taken according to the degree of pandemic risk and resource conditions, that strict prevention and control should be applied to the people not entering through customs, and closed-loop management to the people entering through customs, that entry quarantine measures and quarantine periods should be dynamically adjusted and international exchanges should be gradually resumed in the context of ensuring domestic and overseas epidemic prevention and control in advance, and that it is necessary to integrate medical resources, improve allocation efficiency, and relieve the pressure of resource occupation.

Construction and application of a comprehensive evaluation system for COVID-19 sporadic outbreak in China in the post-epidemic era

This paper constructs an index system for evaluating the efficiency of COVID-19 sporadic outbreak prevention and control from three dimensions (epidemic prevention and control, epidemic traceability, and epidemic background) and with nine sub-indicators (pidemic duration, confirmed cases, detection route, mobile population management policy, flow investigation and tracing, nucleic acid detection, etc.) This evaluation index system is used to calculate and evaluate the control of epidemic in all the 32 regions of Chian since June 1, 2020 to June 1, 2021. Results show that there were significant differences in the efficiency of epidemic prevention and control among these regions, that the intensity of prevention and control measures did not match the severity of the epidemic, and that the management policies for mobile populations across regions lacked a unified yet scientific basis. Based on these, certain epidemic prevention and control management optimization suggestions are presented.

Foreign research progress on social impact and emergency management in the post-pandemic era

We define the concept and analyze the connotation of the post-pandemic era by reviewing the recent foreign research on social impacts, risk prevention and control, and emergency management in the post-pandemic era. The current state of foreign research in the post-pandemic era is outlined, and the progress of foreign research on social impacts like urban planning and travel patterns, as well as core issues like risk prevention and control and emergency management in the post-pandemic era is analyzed in detail. The characteristics and shortcomings of existing research are summarized and future research in the postpandemic era is also forecasted. COVID-19 has had a huge impact on how people socialize, travel, and work, as well as changing industry trends, technical advancements, and social governance. Uncertainty is the most significant risk feature of the post-pandemic era, and the coupling of numerous hazards poses a new set of challenges to emergency management practices.

Immunoglobulin Y Specific for SARS-CoV-2 Spike Protein Subunits Effectively Neutralizes SARS-CoV-2 Infectivity and Ameliorates Disease Manifestations In Vivo.

(Background) The coronavirus disease 2019 (COVID-19) that is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) carries high infectivity and mortality. Efficient intervention strategies are urgently needed. Avian immunoglobulin Y (IgY) showed efficacy against viral infection whereas the in vivo efficacy remains unclear. (Methods) We immunized laying hens with S1, S1 receptor-binding domain (S1-RBD), or S2 subunits of the SARS-CoV-2 spike (S) protein. After immunization, IgYs were collected and extracted from the egg yolks. The neutralization potential of IgYs was examined by the plaque reduction neutralization test (PRNT). The bioutility of IgYs was examined in Syrian hamsters in vivo. (Results) IgYs exhibited typical banding patterns in SDS-PAGE and Western blot and were immunoreactive against S1, S1-RBD, and S2 subunits. The plaque reduction neutralization test (PRNT) showed that all purified IgYs potently neutralized different SARS-CoV-2 strains in vitro. In Syrian hamsters, the combination of IgYs for S1-RBD and S2 subunits administered before or after SARS-CoV-2 infection effectively restored body weight loss and reduced intrapulmonary lesions and the amount of immunoreactive N protein-positive cells, which were caused by SARS-CoV-2 infection. (Conclusions) Collectively, IgYs specific for S protein subunits effectively neutralized SARS-CoV-2 in vitro and in vivo and may serve as prophylactic or therapeutic antibodies in the prevention or treatment of COVID-19.

Coagulation Disorders and Thrombosis in COVID-19 Patients and a Possible Mechanism Involving Endothelial Cells: A Review.

Coronavirus disease 2019 (COVID-19) is still an ongoing pandemic worldwide. COVID-19 is an age-related disease with a higher risk of organ dysfunction and mortality in older adults. Coagulation disorders and thrombosis are important pathophysiological changes in COVID-19 infection. Up to 95% of COVID-19 patients have coagulation disorders characterized by an elevated D-dimer, a prolonged prothrombin time, a low platelet count and other laboratory abnormalities. Thrombosis is found in critical cases with an increased risk of death. Endothelial cells are prone to be affected by the novel SARS-CoV-2 and express angiotensin-converting enzyme 2. The evidence, such as the presence of the virus, has been identified, leading to the inflammation and dysfunction. Endothelial cell activation and dysfunction play a pivotal role in the hypercoagulation status in COVID-19 patients. In addition to the direct exposure of subendothelial tissue to blood, Weibel-Palade bodies within the endothelium containing coagulants can be released into the circulation. Endothelial nitric oxide synthase may be impaired, thus facilitating platelet adhesion. Moreover, anti-ß2-glycoprotein I antibodies may also contribute to the coagulopathy in COVID-19 by inducing the upregulation of proinflammatory mediators and adhesion molecules. To conclude, coagulation disorders and thrombosis are vital and predict a poor outcome in COVID-19 patients, especially in severe cases. Endothelial cell activation and dysfunction may play an important role in causing clot formation. More basic and clinical research is warranted to further our understanding of the role of coagulopathy and their possible mechanism in COVID-19 patients.

Tumor Necrosis Factor-Alpha Exacerbates Viral Entry in SARS-CoV2-Infected iPSC-Derived Cardiomyocytes.

The coronavirus disease 2019 (COVID-19) pandemic with high infectivity and mortality has caused severe social and economic impacts worldwide. Growing reports of COVID-19 patients with multi-organ damage indicated that severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) may also disturb the cardiovascular system. Herein, we used human induced pluripotent stem cell (iPSC)-derived cardiomyocytes (iCMs) as the in vitro platform to examine the consequence of SARS-CoV2 infection on iCMs. Differentiated iCMs expressed the primary SARS-CoV2 receptor angiotensin-converting enzyme-II (ACE2) and the transmembrane protease serine type 2 (TMPRSS2) receptor suggesting the susceptibility of iCMs to SARS-CoV2. Following the infection of iCMs with SARS-CoV2, the viral nucleocapsid (N) protein was detected in the host cells, demonstrating the successful infection. Bioinformatics analysis revealed that the SARS-CoV2 infection upregulates several inflammation-related genes, including the proinflammatory cytokine tumor necrosis factor-α (TNF-α). The pretreatment of iCMs with TNF-α for 24 h, significantly increased the expression of ACE2 and TMPRSS2, SASR-CoV2 entry receptors. The TNF-α pretreatment enhanced the entry of GFP-expressing SARS-CoV2 pseudovirus into iCMs, and the neutralization of TNF-α ameliorated the TNF-α-enhanced viral entry. Collectively, SARS-CoV2 elevated TNF-α expression, which in turn enhanced the SARS-CoV2 viral entry. Our findings suggest that, TNF-α may participate in the cytokine storm and aggravate the myocardial damage in COVID-19 patients.

Risk perception of COVID-19: A comparative analysis of China and South Korea.

The novel coronavirus (COVID-19) has become a pandemic and the risk perception plays an important role in self-protection and spread prevention. This study attempts to explore the intrinsic characteristic of risk perception and the spatial distribution of it, which have not been involved in previous studies. To attach this purpose, data from questionnaire conducted in China and Korea (samples of 897 respondents in China and 340 respondents in South Korea) are used to produce risk perception of COVID- 19. Results reveal four principal findings: (1) risk perception of COVID-19 can be categorized into perceived social risk and perceived risk of being infected; (2) the internal differences are most pronounced in perceived risk of being infected about oneself in China, and in perceived social risk disorder about local community in South Korea; (3) the spatial distribution of risk perception is not consistent with that of epidemic severity, for high-risk perception spread out beyond the epicenter with different performance in the two categories; and (4) among the influence factors, trust in information, familiarity with epidemic situation, and interpersonal distance from suffers in the epicenter are found to have a significant influence on different aspects of risk perception. The theoretical and practical implications of this study enrich the understanding of risk perception of epidemic, and provide specific suggestions for preventing this ongoing epidemic spread across the population.

Sewage Treatment Project Design of Wuhan Huoshenshan and Leishenshan Hospitals

The Huoshenshan hospital and Leishenshan hospital are special infectious diseases hospitals that were designed to focus on the treatment of patients infected by new Coronavirus pneumonia( COVID-19). The design of sewage treatment system was "pre-disinfection contact tank + septic tank + lifting pump station( including crushed grille) + regulating tank + MBBR biochemical tank +coagulation sedimentation tank + contact disinfection tank ". MBBR process could achieve efficient removal of pollutants in sewage at low temperature. Two-stage disinfection process guaranteed 100% virus elimination. At the same time,HDPE membrane was laid under the sewage station according to the landfill standard to ensure the full collection,disinfection and discharge of rainwater and sewage. The sludge was collected and transported as hazardous waste after disinfection and dehydration. The waste gas was collected,deodorized and disinfected in a unified way,so as to realize the full collection and treatment of rainwater,sewage,sludge and waste gas. At present,the operations of the sewage stations of Huoshenshan and Leishenshan hospitals had kept stable,and the relevant effluent indexes met the design requirements. COD concentration was stable below 50 mg/L,ammonia nitrogen was stable below 2 mg/L,residual chlorine was stable near 13 mg/L. Therefore,the pollutant removal and disinfection effect were stable during the whole operation.

Spread and governance of pseudo-science internet rumors in major public healthy emergencies based on SEIR model: a case study of COVID-19 epidemic (Special Section: COVID-19) [Chinese]

By 18:00 on February 16, 2020, the cumulative number of confirmed cases caused by COVID-19 epidemic in China has reached 68,592. The epidemic control work is at a critical period. However, the proliferation of the pseudo-science Internet rumors during the COVID-19 epidemic cause widespread adverse social events, such as the blind rush purchases and hoarding, which seriously affect the epidemic control and the normal social order. Taking the COVID-19 epidemic as an example, this paper reviews the definitions of the pseudo-science and Internet rumors proposed by domestic and foreign scholars. Four major pseudo-science Internet rumors that have had a greater impact in this epidemic, and the data on Sina Weibo(microblog) are used as examples to analyze the spread characteristics of the pseudo-science Internet rumors. Based on the SEIR model, this paper comprehensively analyzes factors such as the lag of official intervention, the bandwagon effect of individual information acceptance, and the spread characteristics of rumors, and the mechanism of the pseudo-science Internet rumors in major public health emergencies through numerical experiments. Finally, this paper proposes countermeasures for the pseudo-science Internet rumors in major public healthy emergencies from various angles.

The influence of risk preference on public purchase behavior: with the purchase of masks as an example (Special Section: COVID-19) [Chinese]

In early 2020, the COVID-19 spread to all parts of China and even other countries in a short period of time. The severe epidemic situation would put a psychological pressure on the public, resulting in anxiety, panic and other emotions, even some irrational behavior such as scare buying and becoming credulous of rumors. The risk preference is defined as the degree of the risk that people are willing to accept in their decisions and behaviors. In this public health emergency, the consumers' purchase and use of sanitary and epidemic prevention products reflects their risk preference. This paper explores the relationship between the public risk preference and the purchase behavior through a questionnaire survey, and it is found that the factors influencing the purchase behavior mainly include the gender factors, the perceived risk level and the severity of the epidemic situation in the residence area, as indicated by the Association Rule Mining.