SARS-CoV-2 Omicron (B.1.1.529) infection in rhesus macaques, hamsters, and BALB/c mice with severe lung histopathological damage.

Since the first SARS-CoV-2 outbreak in late 2019, the SARS-CoV-2 genome has harbored multiple mutations, especially spike protein mutations. The currently fast-spreading Omicron variant that manifests without symptoms or with upper respiratory diseases has been recognized as a serious global public health problem. However, its pathological mechanism is largely unknown. In this work, rhesus macaques, hamsters, and BALB/C mice were employed as animal models to explore the pathogenesis of Omicron (B.1.1.529). Notably, Omicron (B.1.1.529) infected the nasal turbinates, tracheae, bronchi, and lungs of hamsters and BALB/C mice with higher viral loads than in those of rhesus macaques. Severe histopathological damage and inflammatory responses were observed in the lungs of Omicron (B.1.1.529)-infected animals. In addition, viral replication was found in multiple extrapulmonary organs. Results indicated that hamsters and BALB/c mice are potential animal models for studies on the development of drugs/vaccines and therapies for Omicron (B.1.1.529).

Aggravated pneumonia and diabetes in SARS-CoV-2 infected diabetic mice.

Multiple clinical and epidemiological studies have shown an interconnection between coronavirus disease 2019 (COVID-19) and diabetes, but experimental evidence is still lacking. Understanding the interplay between them is important because of the global health burden of COVID-19 and diabetes. We found that C57BL/6J mice were susceptible to the alpha strain of SARS-CoV-2. Moreover, diabetic C57BL/6J mice with leptin receptor gene deficiency (db/db mice) showed a higher viral load in the throat and lung and slower virus clearance in the throat after infection than C57BL/6J mice. Histological and multifactor analysis revealed more advanced pulmonary injury and serum inflammation in SARS-CoV-2 infected diabetic mice. Moreover, SARS-CoV-2 infected diabetic mice exhibited more severe insulin resistance and islet cell loss than uninfected diabetic mice. By RNA sequencing analysis, we found that diabetes may reduce the collagen level, suppress the immune response and aggravate inflammation in the lung after infection, which may account for the greater susceptibility of diabetic mice and their more severe lung damage after infection. In summary, we successfully established a SARS-CoV-2 infected diabetic mice model and demonstrated that diabetes and COVID-19 were risk factors for one another.

The COVID-19 Pandemic, Racism, and Sleep Among Chinese Immigrants in the United States.

The current study aimed to investigate Chinese immigrants' sleep quality and associations between the coronavirus disease 2019 pandemic's impact and racism and sleep disruption using a cross-sectional online survey. A total of 507 Chinese immigrants were recruited via social network sites. The Pittsburgh Sleep Quality Index (PSQI) was used to assess sleep quality. The pandemic's impact and racism were measured using questions developed for this study. More than 42% of participants reported poor sleep quality. Those who reported having been affected by the pandemic had poorer subjective sleep quality, longer sleep latency, and greater daytime dysfunction. Those who experienced racist incidents were more likely to use sleep medication and exhibit poor subjective sleep quality, long sleep latency, short sleep duration, and daytime dysfunction. Chinese immigrants' sleep health warrants particular consideration by health care professionals. Timely, effective interventions, such as relaxation techniques and online psychoeducation, need to be delivered in the Chinese community. [Journal of Psychosocial Nursing and Mental Health Services, xx(x), xx-xx.].

CRISPR-based nucleic acid diagnostics for pathogens

Pathogenic infection remains the primary threat to human health, such as the global COVID-19 pandemic. It is important to develop rapid, sensitive and multiplexed tools for detecting pathogens and their mutated variants, particularly the tailor-made strategies for point-of-care diagnosis allowing for use in resource-constrained settings. The rapidly evolving CRISPR/Cas systems have provided a powerful toolbox for pathogenic diagnostics via nucleic acid tests. In this review, we firstly describe the resultant promising class 2 (single, multidomain effector) and recently explored class 1 (multisubunit effector complexes) CRISPR tools. We present diverse engineering nucleic acid diagnostics based on CRISPR/Cas systems for pathogenic viruses, bacteria and fungi, and highlight the application for detecting viral variants and drug-resistant bacteria enabled by CRISPR-based mutation profiling. Finally, we discuss the challenges involved in on-site diagnostic assays and present emerging CRISPR systems and CRISPR cascade that potentially enable multiplexed and preamplification-free pathogenic diagnostics.

Transmission Dynamics and Epidemiological Characteristics of the SARS-CoV-2 Delta Variant - Hunan Province, China, 2021.

What is already known about this topic?: Little is known about the epidemiology, natural history, and transmission patterns of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Delta variant. Monitoring the evolution of viral fitness of SARS-CoV-2 in the host population is key for preparedness and response planning. What is added by this report?: We analyzed a successfully contained local outbreak of Delta that took place in Hunan, China, and provided estimates of time-to-key event periods, infectiousness over time, and risk factors for SARS-CoV-2 infection and transmission for a still poorly understood variant. What are the implications for public health practice?: Our findings simultaneously shed light on both the characteristics of the Delta variant, by identifying key age groups, risk factors, and transmission pathways, and planning a future response effort against SARS-CoV-2.

CRISPR-based nucleic acid diagnostics for pathogens.

Pathogenic infection remains the primary threat to human health, such as the global COVID-19 pandemic. It is important to develop rapid, sensitive and multiplexed tools for detecting pathogens and their mutated variants, particularly the tailor-made strategies for point-of-care diagnosis allowing for use in resource-constrained settings. The rapidly evolving CRISPR/Cas systems have provided a powerful toolbox for pathogenic diagnostics via nucleic acid tests. In this review, we firstly describe the resultant promising class 2 (single, multidomain effector) and recently explored class 1 (multisubunit effector complexes) CRISPR tools. We present diverse engineering nucleic acid diagnostics based on CRISPR/Cas systems for pathogenic viruses, bacteria and fungi, and highlight the application for detecting viral variants and drug-resistant bacteria enabled by CRISPR-based mutation profiling. Finally, we discuss the challenges involved in on-site diagnostic assays and present emerging CRISPR systems and CRISPR cascade that potentially enable multiplexed and preamplification-free pathogenic diagnostics.

Bacterial drug-resistance and viability phenotyping upon disinfectant exposure revealed by single-nucleotide resolved-allele specific isothermal RNA amplification.

Disinfectant abuse poses a risk of bacterial evolution against stresses, especially during the coronavirus disease 2019 (COVID-19) pandemic. However, bacterial phenotypes, such as drug resistance and viability, are hard to access quickly. Here, we reported an allele specific isothermal RNA amplification (termed AlleRNA) assay, using an isothermal RNA amplification technique, i.e., nucleic acid sequence-based amplification (NASBA), integrated the amplification refractory mutation system (ARMS), involving the use of sequence-specific primers to allow the amplification of the targets with complete complementary sequences. AlleRNA assay enables rapid and simultaneous detection of the single nucleotide polymorphism (SNP) (a detection limit, a LOD of 0.5 % SNP) and the viability (a LOD of 80 CFU) of the quinolone resistant Salmonella enterica. With the use of AlleRNA assay, we found that the quinolone resistant S. enterica exhibited higher survival ability during exposure toquaternary ammonium salt, 75 % ethanol and peracetic acid, which might be attributed to the upregulation of stress response-associated genescompared with the susceptible counterparts. Additionally, the AlleRNA assay indicated the potential risk in a high-frequency occurrence of viable but nonculturable (VBNC) quinolone resistant S. enterica induced by disinfectants due to the depression of ATP biosynthesis. The excessive usage of disinfectants during the COVID-19 pandemic should be carefully evaluated due to the latent threat to ecological and human health.

A follow up study of cycle threshold values of SARS-CoV-2 in Hunan Province, China.

Since the epidemic of the severe acute respiratory syndrome coronavirus 2 (SARS-COV-2), many governments have used reverse transcription polymerase chain reaction (RT-PCR) to detect the virus. However, there are fewer measures of CT values information based on RT-PCR results, and the relationship between CT values and factors from consecutive tests is not clear enough. So in this study, we analyzed the connection between CT values and the factors based on cohort data from Delta variant of SARS-CoV-2 in Hunan Province. Previous studies have showed that the mean age of the cases was 33.34 years (±18.72 years), with a female predominance (55.03%, n = 71), and the greatest proportion of clinical symptoms were of the common type (60.47%, n = 78). There were statistical differences between the N and ORF1ab genes in the CT values for the cases. Based on the analysis of the association between CT values and the factors, the lowest CT values were obtained for the unvaccinated, older and clinically symptomatic group at 3-10 days, the maximum peak of viral load occurred. Therefore, it is recommended to use patient information to focus on older, clinically symptomatic, unvaccinated patients and to intervene promptly upon admission.

A bibliometric analysis of NLRP3 inflammasome in acute lung injury/acute respiratory distress syndrome from 2010 to 2021.

Background: Nod-like receptor family pyrin domain containing 3 (NLRP3) inflammasome is essential in the pathogenesis of acute respiratory distress syndrome (ARDS), a fatal clinical syndrome that deteriorated from acute lung injury (ALI). This bibliometric study aims to offer a thorough insight into the scientific output about NLRP3 inflammasome in ALI/ARDS and explore the intellectual base, developing trajectory and emerging trends. Methods: We retrieved the literature from 2010 to 2021 from Science Citation Index Expanded (SCIE) database. Bibliometrix (3.1.4) R package and CiteSpace (5.8.R3) were used for further analysis and visualization. Results: A total of 508 English articles and reviews published from 2010 to 2021 were identified. The annual number of publications presented a rapidly developing trend especially in recent years. Among all the 42 countries, China was the most productive and most cited country, while the USA had the greatest impact. Peter A. Ward from the USA was the most productive corresponding author, and 4 of these top 10 corresponding authors were from China. The most cited reference was written by Ahmed (2017) of Zhejiang University in China. The Journal of Immunology had highest citation count and G-index. Furthermore, the major disciplines of research front have drifted from "Medicine, Medical, Clinical" to "Molecular, Biology, Immunology" over the past 12 years. In the co-occurring network, the terms "acute lung injury," "NLRP3 inflammasome," "interleukin-1ß," "NF-κB," and "NLRP3 activation" occurred most frequently, while in burst detection, "oxidative stress" had the highest burst strength. Co-citation network revealed that Cluster 2 "virus infection" was the most active area, including the most citation bursts. Cluster 0 "severe COVID-19" and Cluster 1 "dual inhibitor PTUPB" were emerging themes in recent years, and they involved the largest number of publications. Conclusions: This bibliometric analysis revealed a rapid growth trend of the relatively novel topic: NLRP3 inflammasome in ALI/ARDS. China was the largest contributor, while the USA offered the most landmark papers. The major disciplines of research front drifted from "Medicine, Medical, Clinical" to "Molecular, Biology, Immunology." In recent years, studies about the role of NLRP3 in COVID-19-associated ALI/ARDS and oxidative stress became hot spots.

An OX40L mRNA vaccine inhibits the growth of hepatocellular carcinoma.

mRNA cancer vaccines show therapeutic potential for malignant tumors, including hepatocellular carcinoma (HCC). We optimized and synthesized stable mRNA encoding costimulator Oxford 40 ligand (OX40L). For systemic delivery, OX40L mRNAs were loaded into lipid nanoparticles (LNPs). The expression and costimulatory effects of OX40L were investigated in vitro. OX40L was expressed on the cell surface and costimulated T cells. In vivo, intratumoral injection of LNPs encapsulating OX40L mRNAs significantly reduced tumor growth and increased the survival of mice bearing H22 tumors. Importantly, CD4+ and CD8+ T cells were significantly increased in the OX40L mRNA group in vivo. Taken together, our findings provide a promising clinical strategy for immunotherapy for HCC using mRNA vaccines.

Evaluating economic benefits of the revitalization

This article takes Taiwan's Triple Stimulus Vouchers (TSVs) launched in the second half of 2020 as an example to evaluate the economic benefits of revitalization vouchers during the COVID-19 period. We apply scenario settings and input-output tables to evaluate the policy benefits. The main conclusions are as follows: (1) The issuance of TSVs will induce consumers to use revitalized triple vouchers. As the epidemic is under control domestically and border control continues that ruled out non-citizen consumptions, issuing the TSVs during summer vacations generates positive economic benefits. (2) Using promotional activities TSVs are indeed helpful to boost consumer confidence. (3) According to estimates, the benefit of TSVs to real GDP is between NT$45.062 and 83.727 billion;the economic growth rate increases by 0.1173-0.2156%. (4) TSVs have a significant impact on the service industry. The department stores benefited a lot from the TSV policy, and supermarkets and hypermarkets saw rising revenues. Merchants, small shops, and even hawkers in the streets or traditional markets also felt the strength of economic recovery from the retail consumption growth of TSVs, which also brings economic benefits expected by the policy.

Understanding the Impact of COVID-19 Pandemic on Online Shopping and Travel Behaviour: A Structural Equation Modelling Approach

The outbreak of the COVID-19 pandemic has led to significant alterations in people's social and economic behaviour. This paper aims to study the pandemic's influence on online shopping and travel behaviour and discover how these phenomena are related. To this end, eight variables were identified that describe socio-demographic status, COVID-19 variables, online shopping variables, and travel behaviour. The structural equation modelling (SEM) approach was adopted to analyse the relationships between these variables. A conceptual model was formed by devising hypothetical relationships, and then the validity and reliability of the model were evaluated using SEM tools. Among the 19 theoretical relationships, 17 were verified. It was found that socio-demographic status directly affects the COVID-19 variables, influencing online shopping variables. As a result, it was inferred that during the pandemic, people's daily travel habits had been affected by their inclinations toward online shopping, and the more people are aware of COVID-19 and feel responsible about the pandemic, the more they are persuaded to shop online rather than in-person shopping. Policymakers can use the findings of this study to change the public's travel and shopping behaviour to tackle the pandemic.

Bibliometric analysis of global research trends on pyroptosis in lung disease.

Background: Pyroptosis is a lytic pro-inflammatory programmed cell death mode that depends on caspase, inflammasome, and Gasdermin D (GSDMD). A growing number of studies have shown that pyroptosis is closely related to the pathophysiological mechanism of lung. The purpose of this study is to analyze the literature from Science Citation Index Expanded (SCI-expanded) of Web of Science Core Collection (WoSCC) and visualize the current trends and hotspots in the research of pyroptosis in lung disease. Methods: On February 20, 2022, we retrieved all articles on pyroptosis in lung disease from SCI-expanded of WoSCC. Original articles and reviews published in English from 2007 to 2021 were included in the analysis. VOSviewer 1.6.17 and CiteSpace 5.8.R2 were used to analyze the retrieved data and visualize the results. Result: 1798 qualified original articles and reviews on pyroptosis in lung disease were included in the bibliometric analysis. So far, the research in this field is still in a period of growth, and the number of global publications has increased yearly. Among the 66 countries that have published relevant articles, China ranked first in the number of publications, and the USA ranked first in the number of cited articles. Holian,A. was the author with the largest number of articles, including 21 published. The University of California System in the USA was the organization with the largest number of articles, totaling 55. Frontiers in Immunology was the journal with the most publications in pyroptosis. After bibliometric analysis, the frequently used keywords are: "NOD-like receptor3 (NLRP3) inflammasome", "inflammation", "oxidative stress", and "acute lung injury (ALI)". Conclusion: The research on pyroptosis in lung disease is in its growth stage. The information released in this article may help researchers better understand the hotspots and developmental trends in this field, the cooperation network information of authors, countries, and institutions, and the citation correlation between articles. With the in-depth study of the mechanism of pyroptosis, the focus has shifted to increasing research on the connections and influences of different diseases. So far, increasing attention has been paid to the research field of the relationship between ALI and pyroptosis related to COVID-19.

Metabolic modeling of single bronchoalveolar macrophages reveals regulators of hyperinflammation in COVID-19.

SARS-CoV-2 infection induces imbalanced immune response such as hyperinflammation in patients with severe COVID-19. Here, we studied the immunometabolic regulatory mechanisms for the pathogenesis of COVID-19. We depicted the metabolic landscape of immune cells, especially macrophages, from bronchoalveolar lavage fluid of patients with COVID-19 at single-cell level. We found that most metabolic processes were upregulated in macrophages from lungs of patients with mild COVID-19 compared to cells from healthy controls, whereas macrophages from severe COVID-19 showed downregulation of most of the core metabolic pathways including glutamate metabolism, fatty acid oxidation, citrate cycle, and oxidative phosphorylation, and upregulation of a few pathways such as glycolysis. Rewiring cellular metabolism by amino acid supplementation, glycolysis inhibition, or PPARγ stimulation reduces inflammation in macrophages stimulated with SARS-CoV-2. Altogether, this study demonstrates that metabolic imbalance of bronchoalveolar macrophages may contribute to hyperinflammation in patients with severe COVID-19 and provides insights into treating COVID-19 by immunometabolic modulation.

Bibliometric analysis of global research trends on pyroptosis in lung disease

Background Pyroptosis is a lytic pro-inflammatory programmed cell death mode that depends on caspase, inflammasome, and Gasdermin D (GSDMD). A growing number of studies have shown that pyroptosis is closely related to the pathophysiological mechanism of lung. The purpose of this study is to analyze the literature from Science Citation Index Expanded (SCI-expanded) of Web of Science Core Collection (WoSCC) and visualize the current trends and hotspots in the research of pyroptosis in lung disease. Methods On February 20, 2022, we retrieved all articles on pyroptosis in lung disease from SCI-expanded of WoSCC. Original articles and reviews published in English from 2007 to 2021 were included in the analysis. VOSviewer 1.6.17 and CiteSpace 5.8.R2 were used to analyze the retrieved data and visualize the results. Result 1798 qualified original articles and reviews on pyroptosis in lung disease were included in the bibliometric analysis. So far, the research in this field is still in a period of growth, and the number of global publications has increased yearly. Among the 66 countries that have published relevant articles, China ranked first in the number of publications, and the USA ranked first in the number of cited articles. Holian,A. was the author with the largest number of articles, including 21 published. The University of California System in the USA was the organization with the largest number of articles, totaling 55. Frontiers in Immunology was the journal with the most publications in pyroptosis. After bibliometric analysis, the frequently used keywords are: “NOD-like receptor3 (NLRP3) inflammasome”, “inflammation”, “oxidative stress”, and “acute lung injury (ALI)”. Conclusion The research on pyroptosis in lung disease is in its growth stage. The information released in this article may help researchers better understand the hotspots and developmental trends in this field, the cooperation network information of authors, countries, and institutions, and the citation correlation between articles. With the in-depth study of the mechanism of pyroptosis, the focus has shifted to increasing research on the connections and influences of different diseases. So far, increasing attention has been paid to the research field of the relationship between ALI and pyroptosis related to COVID-19.

Evolution Model and Simulation Study of the Public Risk Perception of COVID-19.

The evolution of the public perception of the risk in public health emergencies is closely related to risk response behavior. There are few systematic explanations and empirical studies on how the individual receiving the risk information affects the change in the individual risk perception through internal mechanisms in the context of COVID-19. Based on the understanding of the existing research, this paper constructs the evolution model of the public risk perception level based on the limited memory theory and a simulation analysis is performed. The results are as follows: memory rate, association rate, information reception and information stimulation in a single period of time have significant indigenous effects on the risk perception; when the amount of information received and the information stimulus remain unchanged, the public's risk perception follows a monotonic upward trend, but there is an upper limit function, and the upper limit is determined by the memory rate and association rate, and the influence of the association rate is higher than that of the memory rate; When the amount of information received and the information stimulus changes, the public's risk perception will also change, and there is a lag effect, which is determined by the memory rate. The impact of the acceptance of the information on the risk perception is greater than that of the information stimulus.

Influencing Factors of Students Aged 10-20 Non-participating in Home Physical Exercise During the COVID-19 Isolation Policy Period: A Cross-Sectional Study From China.

Background: A number of public health measures are required during the COVID-19 pandemic. To stop the spread of COVID-19, the Chinese government has adopted isolation policies, including closing non-essential businesses, public transportation and schools, moving students' face-to-face learning to online, and recommending the cancellation of all non-essential activities and outdoor activities. However, while this isolation strategy has reduced human-to-human transmission of COVID-19, it has led to dramatic changes in students' daily lives and learning styles, including reduced physical activity and increased sedentary time. Considering the potentially harmful effects of physical inactivity, this study hoped to explore the incidence and influencing factors of non-participation in home physical exercise among Chinese students aged 10-20 during the implementation of the COVID-19 isolation policy. Methods: Through an online questionnaire platform, this study created an open-ended questionnaire (from March 1, 2020 to March 10, 2020) and distributed it to students in areas where isolation policies were enforced. The questionnaire was initially distributed by 10 recruited volunteers, and then the questionnaire was voluntarily forwarded and shared by the subjects or others, in a "snowball" way, to expand distribution. Finally, the survey data of 4,532 Chinese students aged 10-20 were collected. The incidence of respondents non-participating in home physical activity was determined using univariate analysis. Using odds ratios and 95% confidence intervals of a multivariate binary logistic regression model, factors influencing non-participation in home physical exercise were estimated. Results: Among the sample students, the incidence rate of non-participating in home physical exercise was 25.86% (24.06-27.15%). Exercise intentions, exercise habits, self-assessed health, beliefs in physical health, family exercise, family exercise recommendations, home exercise conditions, school exercise guidance, and health education programs had a negative impact on students non-participating in home physical exercise. Academic performance and electronic product use had a positive effect on non-participating in home physical exercise. Conclusions: A variety of forward leaning factors, enabling factors and demand factors have affected the occurrence of students" non-participating in home physical exercise. Future health isolation policies should take into account these influencing factors to reduce the occurrence of students" non-participating in home physical exercise and to promote students' independent participation in physical exercise.

The role of vaccines in COVID-19 control strategies in Singapore and China.

Objectives: In this article, we critically review the development and implementation of COVID-19 vaccination in Singapore and China during the pandemic. Methods: We collect and analyze data from a range of sources, including scholarly articles, statistics and documents from national governments in the two countries, and reports from international organizations. Results: There are important differences in the two countries' approaches to the evolving pandemic, and thus the roles that COVID-19 vaccination plays in the overall response strategies in these two countries. Conclusions: Whereas Singapore adopted a "living with the virus" strategy, China continued to pursue a COVID-zero strategy. The overall COVID-19 response strategy of Singapore was largely shared by many countries in the world, while that of China was more unique and hardly imitated elsewhere. Nevertheless, vaccination played a significant role in both countries' responses to the pandemic. A comparison and contrast between the vaccination processes in these two countries thus shed important light on the drivers and outcomes of COVID-19 vaccination in different settings.

An Investigation on Chinese Public Acceptance of COVID-19 Prevention Measures.

China has basically succeeded in bringing the COVID-19 epidemic under control, thanks to a timely series of effective prevention and control measures taken by the Chinese government. In this study, a public acceptance questionnaire of epidemic prevention measures was designed to investigate the influencing factors of public acceptance. A total of 2062 samples were collected from 8 March 2020 to 9 April 2020, and Independent-Samples T-Test and One-way ANOVA were used to analyze the data collected in the questionnaire in SPSS version 22.0. The results show that age and educational level have a significant influence on public acceptance. With the development of the epidemic, the acceptability grew generally higher. The public acceptance of traffic measures is the highest. This study summarises China's scientific experience in the fight against COVID-19 and the differences in public acceptance. It can provide a positive reference for the development of epidemic prevention in other countries.

Characteristic analysis of Omicron‐included SARS‐CoV‐2 variants of concern

In view of the rapid development of the COVID‐19 pandemic and SARS‐CoV‐2 mutation, we characterized the emerging SARS‐CoV‐2 variants of concern (VOCs) by both bioinformatics methods and experiments. The representative genomic sequences of SARS‐CoV‐2 VOCs were first downloaded from NCBI, including the prototypic strain, Alpha (B.1.1.7) strain, Beta (B.1.351) strain, Delta (B.1.617.2), and Omicron (B1.1.529) strain. Bioinformatics analysis revealed that the D614G mutation led to formation of a protruding spike (S) in the tertiary structure of spike protein, which could be responsible for the enhanced binding to angiotensin‐converting enzyme 2 (ACE2) receptor. The epitope analysis further showed that the S protein antigenicity of the Omicron variant changed dramatically, which was possibly associated with its enhanced ability of immune escape. To verify the bioinformatics results, we performed experiments of pseudovirus infection and protein affinity assay. Notably, we found that the spike protein of Omicron variant showed the weakest infectivity and binding ability among all tested strains. Finally, we also proved this through virus infection experiments, and found that the cytotoxicity of Omicron seems to be not strong enough. The results in this study provide guidelines for prevention and control of COVID‐19. In this study, we first predicted and compared the structure of the S protein and B‐cell epitopes of different SARS‐CoV‐2 variants. Then, the binding ability of different SARS‐CoV‐2 variant S proteins to angiotensin‐converting enzyme 2 (ACE2) cells and the affinity of RBD region to ACE2 were further compared through pseudovirus infection and intermolecular binding ability test. Finally, cell infection experiments were performed. The results unexpectedly showed that Omicron possesses lower ACE2 binding capacity, and lower replication capacity than Delta strain.