Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 20 de 64
Filter
Add filters

Year range
1.
Biosensors & bioelectronics ; 2022.
Article in English | EuropePMC | ID: covidwho-1615442

ABSTRACT

The development of reliable, sensitive, and fast devices for the diagnosis of COVID-19 is of great importance in the pandemic of the new coronavirus. Here, we proposed a new principle of analysis based on a combination of reverse transcription and isothermal amplification of a fragment of the gene encoding the S protein of the SARS-CoV-2 and the CRISPR/Cas13a reaction for cleavage of the specific probe. As a result, the destroyed probe cannot be detected on an immunochromatographic strip using quantum fluorescent dots. Besides, the results can be obtained by an available and inexpensive portable device. By detecting SARS-CoV-2 negative (n = 25) and positive (n = 62) clinical samples including throat swabs, sputum and anal swabs, the assay showed good sensitivity and specificity of the method and could be completed within 1 h without complicated operation and expensive equipment. These superiorities showed its potential for fast point-of-care screening of SARS-CoV-2 during the outbreak, especially in remote and underdeveloped areas with limited equipment and resources.

2.
Front Vet Sci ; 8: 794228, 2021.
Article in English | MEDLINE | ID: covidwho-1590783

ABSTRACT

Spike (S) glycoprotein is an important virulent factor for coronaviruses (CoVs), and variants of CoVs have been characterized based on S gene analysis. We present phylogenetic relationship of an isolated infectious bronchitis virus (IBV) strain with reference to the available genome and protein sequences based on network, multiple sequence, selection pressure, and evolutionary fingerprinting analysis in People's Republic of China. One hundred and elven strains of CoVs i.e., Alphacoronaviruses (Alpha-CoVs; n = 12), Betacoronaviruses (Beta-CoVs; n = 37), Gammacoronaviruses (Gamma-CoVs; n = 46), and Deltacoronaviruses (Delta-CoVs; n = 16) were selected for this purpose. Phylogenetically, SARS-CoV-2 and SARS-CoVs clustered together with Bat-CoVs and MERS-CoV of Beta-CoVs (C). The IBV HH06 of Avian-CoVs was closely related to Duck-CoV and partridge S14, LDT3 (teal and chicken host). Beluga whale-CoV (SW1) and Bottlenose dolphin-CoVs of mammalian origin branched distantly from other animal origin viruses, however, making group with Avian-CoVs altogether into Gamma-CoVs. The motif analysis indicated well-conserved domains on S protein, which were similar within the same phylogenetic class and but variable at different domains of different origins. Recombination network tree indicated SARS-CoV-2, SARS-CoV, and Bat-CoVs, although branched differently, shared common clades. The MERS-CoVs of camel and human origin spread branched into a different clade, however, was closely associated closely with SARS-CoV-2, SARS-CoV, and Bat-CoVs. Whereas, HCoV-OC43 has human origin and branched together with bovine CoVs with but significant distant from other CoVs like SARS CoV-2 and SARS-CoV of human origin. These findings explain that CoVs' constant genetic recombination and evolutionary process that might maintain them as a potential veterinary and human epidemic threat.

3.
PLoS One ; 16(11): e0259097, 2021.
Article in English | MEDLINE | ID: covidwho-1575776

ABSTRACT

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) poses a high risk of transmission in close-contact indoor settings, which may include households. Prior studies have found a wide range of household secondary attack rates and may contain biases due to simplifying assumptions about transmission variability and test accuracy. METHODS: We compiled serological SARS-CoV-2 antibody test data and prior SARS-CoV-2 test reporting from members of 9,224 Utah households. We paired these data with a probabilistic model of household importation and transmission. We calculated a maximum likelihood estimate of the importation probability, mean and variability of household transmission probability, and sensitivity and specificity of test data. Given our household transmission estimates, we estimated the threshold of non-household transmission required for epidemic growth in the population. RESULTS: We estimated that individuals in our study households had a 0.41% (95% CI 0.32%- 0.51%) chance of acquiring SARS-CoV-2 infection outside their household. Our household secondary attack rate estimate was 36% (27%- 48%), substantially higher than the crude estimate of 16% unadjusted for imperfect serological test specificity and other factors. We found evidence for high variability in individual transmissibility, with higher probability of no transmissions or many transmissions compared to standard models. With household transmission at our estimates, the average number of non-household transmissions per case must be kept below 0.41 (0.33-0.52) to avoid continued growth of the pandemic in Utah. CONCLUSIONS: Our findings suggest that crude estimates of household secondary attack rate based on serology data without accounting for false positive tests may underestimate the true average transmissibility, even when test specificity is high. Our finding of potential high variability (overdispersion) in transmissibility of infected individuals is consistent with characterizing SARS-CoV-2 transmission being largely driven by superspreading from a minority of infected individuals. Mitigation efforts targeting large households and other locations where many people congregate indoors might curb continued spread of the virus.


Subject(s)
COVID-19/epidemiology , COVID-19/transmission , Family Characteristics , Humans , Incidence , Likelihood Functions , Pandemics/statistics & numerical data , SARS-CoV-2/pathogenicity , Sensitivity and Specificity , Serologic Tests/methods , Utah/epidemiology
4.
J Ophthalmol ; 2021: 2678706, 2021.
Article in English | MEDLINE | ID: covidwho-1559286

ABSTRACT

Background: We aimed to investigate the symptoms of the dry eye disease (DED) of hospitalized patients with coronavirus disease 2019 (COVID-19). Methods: This cross-sectional, observational study analysis included 91 hospitalized patients with confirmed COVID-19 in Wuhan, China. The Ocular Surface Disease Index (OSDI) and the five-item Dry Eye Questionnaire (DEQ-5) were used to assess the severity of DED symptoms in the patients, and the analysis of variance was used to determine the factors associated with DED. Results: A total of 42 patients consented to complete the investigation (response rate 46.15%). There were 26 (61.90%) patients who were diagnosed with DED symptoms by OSDI, and there were 28 (66.67%) patients with DED symptoms who were diagnosed by DEQ-5 score. For the biochemical tests, the patients with DED symptoms had lower aspartate aminotransferase (AST) levels compared to those with no DED symptoms (20.86 vs. 42.14, p=0.04). Further analysis showed that a previous history of cardiac or stroke disease (p=0.02) and typical symptoms of muscle soreness (p=0.03) were significantly different among the four DED symptoms groups on the basis of OSDI scores. The contributing factors of OSDI were mainly focused on visual function and environmental triggers. Conclusion: The incidence of DED symptoms is higher in hospitalized patients with COVID-19. The serum AST levels, history of cardiac or stroke disease, and the typical symptoms of muscle soreness may be the main impact factors on DED symptoms. We also need to pay more attention to the visual function and environmental triggers of hospitalized patients with COVID-19.

5.
Preprint in English | EuropePMC | ID: ppcovidwho-296434

ABSTRACT

Background: The onset of various kidney diseases have been reported after COVID-19 vaccination. However, detailed clinical and pathological examination of kidney injury in patients receiving inactivated vaccines are lacking.<br><br>Methods: We screened and analyzed patients with newly diagnosed kidney diseases after inactivated SARS-CoV-2 vaccination in Peking University First Hospital from January 2021 to August 2021. We obtained samples of blood, urine, and renal biopsy tissues. Clinical and laboratory information, as well as light microscopy, immunostaining and ultrastructural observation were described. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Spike protein and Nucleoprotein were stained using immune-fluorescence technique in the kidney biopsy samples. SARS-CoV-2 specific antibodies were tested using magnetic particle chemiluminescence immunoassay.<br><br>Findings: The study group included 17 patients, including immune complex mediated kidney diseases (IgA nephropathy, membranous nephropathy and lupus nephritis), podocytopathy (minimal change disease and focal segmental glomerulosclerosis) and others (antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis, anti-GBM nephritis, acute tubulointerstitial nephritis, and thrombotic microangiopathy). Seven patients (41.18%) developed renal disease after the first dose and 10 (58.82%) after the second dose. We found no definitive evidence of SARS-CoV-2 Spike protein or Nucleoprotein deposition in the kidney biopsy samples. Serological markers implicated abnormal immune responses in predisposed individuals. Treatment and follow-up (median = 86 days) showed that biopsy diagnosis informed treatment and prognosis in all patients.<br><br>Interpretation: We observed various kidney diseases following inactivated SARS-CoV-2 vaccine administration. Our findings provide an evidence against direct vaccine protein deposition as the major pathomechanism, but implicate abnormal immune responses in predisposed individuals. These findings expand our understanding of inactivated SARS-CoV-2 vaccine renal safety.<br><br>Funding: This study was funded by National Natural Science Foundation of China (91742205, 82170711, 81800636, 82070733, 81625004), Clinical Medicine Plus X—Young Scholars Project of Peking University (PKU2021LCXQ017), the Fundamental Research Funds for the Central Universities, CAMS Innovation Fund for Medical Sciences (2019-I2M-5-046), Yunnan Provincial Science and Technology Department (202102AA100051 and 202003AC100010, China), and Beijing Young Scientist Program (BJJWZYJH01201910001006).<br><br>Declaration of Interest: The authors declare no competing interests.<br><br>Ethical Approval: This study was approved by the institutional review board of Peking University First Hospital (2021-352) and the Committee on Human Subject Research and Ethics of Yunnan University (CHSRE2021020). Written Informed Consent Form was obtained from each participant.

6.
Emerg Microbes Infect ; : 1-35, 2021 Dec 03.
Article in English | MEDLINE | ID: covidwho-1550502

ABSTRACT

The ubiquitously-expressed proteolytic enzyme furin is closely related to the pathogenesis of SARS-CoV-2, and therefore represents a key target for antiviral therapy. Based on bioinformatic analysis and pseudovirus tests, we discovered a second functional furin site located in the spike protein. Furin still increased the infectivity of mutated SARS-CoV-2 pseudovirus in 293T-ACE2 cells when the canonical polybasic cleavage site (682-686) was deleted. However, K814A mutation eliminated the enhancing effect of furin on virus infection. Furin inhibitor prevented infection by 682-686-deleted SARS-CoV-2 in 293T-ACE2-furin cells, but not the K814A mutant. K814A mutation did not affect the activity of TMPRSS2 and cathepsin L but did impact the cleavage of S2 into S2' and cell-cell fusion. Additionally, we showed that this functional furin site exists in RaTG13 from bat and PCoV-GD/GX from pangolin. Therefore, we discovered a new functional furin site which is pivotal in promoting SARS-CoV-2 infection.

7.
Materials (Basel) ; 14(23)2021 Nov 23.
Article in English | MEDLINE | ID: covidwho-1542648

ABSTRACT

Flexible sensors have attracted extensive attention because of their promising applications in the fields of health monitoring, intelligent robots, and electronic skin, etc. During the COVID-19 epidemic, noncontact control of public equipment such as elevators, game consoles, and doors has become particularly important, as it can effectively reduce the risk of cross-infection. In this work, a noncontact flexible temperature sensor is prepared via a simple dip-drying progress, in which poly(3,4-ethylenedioxythiophene):poly(4-styrene sulfonate) (PEDOT:PSS) and printer paper served as the sensing material and the flexible substrate, respectively. We combined the highly sensitive temperature-responsive property of PEDOT:PSS with the good hygroscopicity of printer paper. The prepared sensor shows high sensitivity and good stability in noncontact sensing mode within the temperature range of 20-50 °C. To prove the practicability of the noncontact temperature sensor, a 3 × 2 sensing array is prepared as a noncontact human-machine interface to realize the interaction between player and "Pound-A-Mole game" and a Bluetooth car. These two demos show the sensor's ability to perceive nearby temperature changes, verifying its application potential as a noncontact human-machine interaction interface.

8.
Adv Mater ; : e2105865, 2021 Nov 08.
Article in English | MEDLINE | ID: covidwho-1530085

ABSTRACT

Monitoring the body temperature with high accuracy provides a fast, facile, yet powerful route about the human body in a wide range of health information standards. Here, the first ever ultrasensitive and stretchable gold-doped silicon nanomembrane (Au-doped SiNM) epidermal temperature sensor array is introduced. The ultrasensitivity is achieved by shifting freeze-out region to intrinsic region in carrier density and modulation of fermi energy level of p-type SiNM through the development of a novel gold-doping strategy. The Au-doped SiNM is readily transferred onto an ultrathin polymer layer with a well-designed serpentine mesh structure, capable of being utilized as an epidermal temperature sensor array. Measurements in vivo and in vitro show temperature coefficient of resistance as high as -37270.72 ppm °C-1 , 22 times higher than existing metal-based temperature sensors with similar structures, and one of the highest thermal sensitivity among the inorganic material based temperature sensors. Applications in the continuous monitoring of body temperature and respiration rate during exercising are demonstrated with a successful capture of information. This work lays a foundation for monitoring body temperature, potentially useful for precision diagnosis (e.g., continuous monitoring body temperature in coronavirus disease 2019 cases) and management of disease relevance to body temperature in healthcare.

9.
Preprint in English | [Unspecified Source] | ID: ppcovidwho-292777

ABSTRACT

Background: The 2019 novel coronavirus (2019-nCoV) has affected more than 72,000 people worldwide and caused more than 1,800 deaths so far. 2019-nCoV uses the angiotensinconverting enzyme 2 (ACE2) as the cell receptor to invade the human host and primarily causes pneumonia. Thus, ACE2 is the key to understanding the mechanism of 2019-nCoV infection. Methods: We compared ACE2 expression levels across 31 human normal tissues, between males and females, and between younger (ages <= 49 years) and older (ages > 49 years) persons in these tissues. We also investigated the correlations between ACE2 expression and immune signatures in various tissues. Results: ACE2 expression levels were the highest in small intestine, testis, kidney, heart, thyroid, and adipose tissue, and were the lowest in blood, spleen, bone marrow, brain, blood vessel, and muscle. In lungs, colon, liver, bladder, and adrenal gland, ACE2 showed the medium expression levels. ACE2 was not differentially expressed between males and females and between younger and older persons in any tissue. In skin, digestive system, brain, and blood vessel, ACE2 expression levels were positively associated with immune signatures in both males and females. In thyroid and lungs, ACE2 expression levels were positively and negatively associated with immune signatures in males and females, respectively. Conclusions: Our data provide potential cues for the 2019-nCoV epidemic may infect other tissues outside lungs, affect males and females and young and old persons equally, and old age and male are associated with higher mortality risk for 2019-nCoV infection.

10.
J Affect Disord ; 292: 89-94, 2021 09 01.
Article in English | MEDLINE | ID: covidwho-1525831

ABSTRACT

BACKGROUND: The purpose of this study was to explore the association between perceived stress and depression among medical students and the mediating role of insomnia in this relationship during the COVID-19 pandemic in China. METHODS: A cross-sectional survey was conducted from March to April 2020 in medical university. Levels of perceived stress, insomnia and depression were measured using Perceived Stress Scale (PSS), Insomnia Severity Index (ISI) and Patient Health Questionnaire 9 (PHQ-9). The descriptive analyses of the demographic characteristics and correlation analyses of the three variables were calculated. The significance of the mediation effect was obtained using a bootstrap approach with SPSS PROCESS macro. RESULTS: The mean age of medical students was 21.46 years (SD=2.50). Of these medical students, 10,185 (34.3%) were male and 19,478 (65.7%) were female. Perceived stress was significantly associated with depression (ß=0.513, P < 0.001). Insomnia mediated the association between perceived stress and depression (ß=0.513, P < 0.001). The results of the non-parametric bootstrapping method confirmed the significance of the indirect effect of perceived stress through insomnia (95% bootstrap CI =0.137, 0.149). The indirect effect of insomnia accounted for 44.13% of the total variance in depression. CONCLUSIONS: These findings contribute to a better understanding of the interactive mechanisms underlying perceived stress and depression, and elucidating the mediating effects of insomnia on the association. This research provides a useful theoretical and methodological approach for prevention of depression in medical students. Findings from this study indicated that it may be effective to reduce depression among medical students by improving sleep quality and easing perceived stress.


Subject(s)
COVID-19 , Sleep Initiation and Maintenance Disorders , Students, Medical , Adult , Anxiety , China/epidemiology , Cross-Sectional Studies , Depression/epidemiology , Disease Outbreaks , Female , Humans , Male , Pandemics , SARS-CoV-2 , Sleep Initiation and Maintenance Disorders/epidemiology , Stress, Psychological/epidemiology , Young Adult
12.
The American Journal of Gastroenterology ; 116, 2021.
Article in English | ProQuest Central | ID: covidwho-1478587
13.
Int J Environ Res Public Health ; 18(20)2021 10 16.
Article in English | MEDLINE | ID: covidwho-1470862

ABSTRACT

Although the health and economic risks of COVID-19 may differ for higher- and lower-socioeconomic-status (SES) populations, some studies found that people with lower SES do not necessarily experience more psychological panic. In this research, we examine how SES is related with psychological panic during the COVID-19 pandemic using a large nationwide Chinese sample. Participants were 933 adults (mean age = 30.04, SD = 8.19) who completed an online questionnaire between 11 and 12 February 2020. Lower SES individuals have higher trust in government and thus experience less psychological panic, and the indirect effect of this trust suppresses the direct negative association between SES and psychological panic. In addition to this difference in trust in government between lower- and higher-status individuals, the indirect effect of the trust only exists among people with low (not high) authoritarian personalities. This study provides evidence that political trust may serve as a buffer, suppressing the negative association between SES and psychological panic; thus, policies and actions enhancing political trust are vital to support the mental health of individuals with lower SES during the pandemic, especially for citizens with low authoritarian personalities.


Subject(s)
COVID-19 , Trust , Adult , China/epidemiology , Cross-Sectional Studies , Government , Humans , Pandemics , Personality , SARS-CoV-2 , Social Class
14.
Commun Biol ; 4(1): 1196, 2021 10 13.
Article in English | MEDLINE | ID: covidwho-1467140

ABSTRACT

Emerging mutations in SARS-CoV-2 cause several waves of COVID-19 pandemic. Here we investigate the infectivity and antigenicity of ten emerging SARS-CoV-2 variants-B.1.1.298, B.1.1.7(Alpha), B.1.351(Beta), P.1(Gamma), P.2(Zeta), B.1.429(Epsilon), B.1.525(Eta), B.1.526-1(Iota), B.1.526-2(Iota), B.1.1.318-and seven corresponding single amino acid mutations in the receptor-binding domain using SARS-CoV-2 pseudovirus. The results indicate that the pseudovirus of most of the SARS-CoV-2 variants (except B.1.1.298) display slightly increased infectivity in human and monkey cell lines, especially B.1.351, B.1.525 and B.1.526 in Calu-3 cells. The K417N/T, N501Y, or E484K-carrying variants exhibit significantly increased abilities to infect mouse ACE2-overexpressing cells. The activities of furin, TMPRSS2, and cathepsin L are increased against most of the variants. RBD amino acid mutations comprising K417T/N, L452R, Y453F, S477N, E484K, and N501Y cause significant immune escape from 11 of 13 monoclonal antibodies. However, the resistance to neutralization by convalescent serum or vaccines elicited serum is mainly caused by the E484K mutation. The convalescent serum from B.1.1.7- and B.1.351-infected patients neutralized the variants themselves better than other SARS-CoV-2 variants. Our study provides insights regarding therapeutic antibodies and vaccines, and highlights the importance of E484K mutation.


Subject(s)
COVID-19/virology , SARS-CoV-2/genetics , SARS-CoV-2/immunology , Animals , Antibodies, Monoclonal/immunology , Antibodies, Neutralizing/genetics , Antibodies, Neutralizing/immunology , COVID-19/immunology , COVID-19/therapy , Cell Line , HEK293 Cells , Humans , Immunization, Passive/methods , Mammals/immunology , Mice , Mutation , Pandemics , Primates/immunology , Protein Binding , Tropism/genetics
15.
BMC Psychiatry ; 21(1): 498, 2021 10 12.
Article in English | MEDLINE | ID: covidwho-1468051

ABSTRACT

OBJECTIVE: The novel coronavirus disease 2019 (COVID-19) is a global public health emergency that has caused worldwide concern. The mental health of medical students under the COVID-19 epidemic has attracted much attention. This study aims to identify subgroups of medical students based on depression and anxiety and explore the influencing factors during the COVID-19 epidemic in China. METHODS: A total of 29,663 medical students were recruited during the epidemic of COVID-19 in China. Depression and anxiety symptoms were assessed using Patient Health Questionnaire 9 (PHQ9) and Generalized Anxiety Disorder 7 (GAD7) respectively. Latent class analysis was performed based on depression and anxiety symptoms in medical students. The latent class subtypes were compared using the chi-square test. Multinomial logistic regression was used to examine associations between identified classes and related factors. RESULTS: In this study, three distinct subgroups were identified, namely, the poor mental health group, the mild mental health group and the low symptoms group. The number of medical students in each class is 4325, 9321 and 16,017 respectively. The multinomial logistic regression results showed that compared with the low symptoms group, the factors influencing depression and anxiety in the poor mental health group and mild mental health group were sex, educational level, drinking, individual psychiatric disorders, family psychiatric disorders, knowledge of COVID-19, fear of being infected, and participate in mental health education on COVID-19. CONCLUSIONS: Our findings suggested that latent class analysis can be used to categorize different medical students according to their depression and anxiety symptoms during the outbreak of COVID-19. The main factors influencing the poor mental health group and the mild mental health group are basic demographic characteristics, disease history, COVID-19 related factors and behavioural lifestyle. School administrative departments can carry out targeted psychological counseling according to different subgroups to promote the physical and mental health of medical students.


Subject(s)
COVID-19 , Epidemics , Students, Medical , Anxiety/epidemiology , Anxiety Disorders/epidemiology , China/epidemiology , Cross-Sectional Studies , Depression/epidemiology , Humans , Latent Class Analysis , SARS-CoV-2 , Surveys and Questionnaires
16.
Viruses ; 13(9)2021 09 14.
Article in English | MEDLINE | ID: covidwho-1411090

ABSTRACT

The porcine epidemic diarrhea virus (PEDV) is an Alphacoronavirus (α-CoV) that causes high mortality in infected piglets, resulting in serious economic losses in the farming industry. Hypericin is a dianthrone compound that has been shown as an antiviral activity on several viruses. Here, we first evaluated the antiviral effect of hypericin in PEDV and found the viral replication and egression were significantly reduced with hypericin post-treatment. As hypericin has been shown in SARS-CoV-2 that it is bound to viral 3CLpro, we thus established a molecular docking between hypericin and PEDV 3CLpro using different software and found hypericin bound to 3CLpro through two pockets. These binding pockets were further verified by another docking between hypericin and PEDV 3CLpro pocket mutants, and the fluorescence resonance energy transfer (FRET) assay confirmed that hypericin inhibits the PEDV 3CLpro activity. Moreover, the alignments of α-CoV 3CLpro sequences or crystal structure revealed that the pockets mediating hypericin and PEDV 3CLpro binding were highly conserved, especially in transmissible gastroenteritis virus (TGEV). We then validated the anti-TGEV effect of hypericin through viral replication and egression. Overall, our results push forward that hypericin was for the first time shown to have an inhibitory effect on PEDV and TGEV by targeting 3CLpro, and it deserves further attention as not only a pan-anti-α-CoV compound but potentially also as a compound of other coronaviral infections.


Subject(s)
Alphacoronavirus/drug effects , Alphacoronavirus/physiology , Anthracenes/pharmacology , Antiviral Agents/pharmacology , Coronavirus 3C Proteases/antagonists & inhibitors , Coronavirus Infections/virology , Perylene/analogs & derivatives , Virus Replication/drug effects , Amino Acid Sequence , Animals , Antiviral Agents/chemistry , Chlorocebus aethiops , Coronavirus 3C Proteases/chemistry , Enzyme Activation/drug effects , Models, Molecular , Perylene/pharmacology , Porcine epidemic diarrhea virus/drug effects , Recombinant Proteins , Structure-Activity Relationship , Swine , Swine Diseases/virology , Vero Cells
17.
Pathogens ; 10(9)2021 Aug 30.
Article in English | MEDLINE | ID: covidwho-1390712

ABSTRACT

The sharp increase in the proportion of asymptomatic cases and the potential risk of virus transmission have greatly increased the difficulty of controlling the COVID-19 pandemic. The individual immune response is closely associated with clinical outcomes and pathogenic mechanisms of COVID-19. However, the clinical characteristics and immunophenotyping features of immune cells of asymptomatic individuals remain somewhat mysterious. To better understand and predict the disease state and progress, we performed a comprehensive analysis of clinical data, laboratory indexes and immunophenotyping features in 41 patients with SARS-CoV-2 (including 24 asymptomatic cases and 17 symptomatic individuals). Firstly, from the perspective of demographic characteristics, the rate of asymptomatic infection was significantly higher in those with younger age. Secondly, the laboratory test results showed that some indexes, such as CRP (acute phase reaction protein), D-Dimer and fibrinogen (the marker for coagulation) were lower in the asymptomatic group. Finally, symptomatic individuals were prone to establishing a non-protective immune phenotype by abnormally decreasing the lymphocyte count and percentage, abnormally increasing the Th17 percentage and decreasing Treg percentage, which therefore cause an increase in the neutrophil/lymphocyte ratio (NLR), monocytes/lymphocytes ratio (MLR) and Th17/Treg ratio. On the other hand, asymptomatic individuals tended to establish a more effective and protective immune phenotype by maintaining a normal level of lymphocyte count and percentage and a high level of NK cells. At the same time, asymptomatic individuals can establish a relatively balanced immune response through maintaining a low level of monocytes, a relatively low level of Th17 and high level of Treg, which therefore lead to a decrease in MNKR and Th17/Treg ratio and finally the avoidance of excessive inflammatory responses. This may be one of the reasons for their asymptomatic states. This study is helpful to reveal the immunological characteristics of asymptomatic individuals, understand immune pathogenesis of COVID-19 and predict clinical outcomes more precisely. However, owing to small sample sizes, a future study with larger sample size is still warranted.

18.
Immun Inflamm Dis ; 9(4): 1186-1196, 2021 12.
Article in English | MEDLINE | ID: covidwho-1384181

ABSTRACT

Neutrophils play multiple roles in acute viral infections. They restrict viral replication and diffusion through phagocytosis, degranulation, respiratory burst, secretion of cytokines, and the release of neutrophil extracellular traps, as well as, activate the adaptive immune response. However, the overactivation of neutrophils may cause tissue damage and lead to poor outcomes. Additionally, some characteristics and functions of neutrophils, such as cell number, lifespan, and antiviral capability, can be influenced while eliminating viruses. This review provides a general description of the protective and pathological roles of neutrophils in acute viral infection.


Subject(s)
Extracellular Traps , Virus Diseases , Adaptive Immunity , Humans , Neutrophils , Phagocytosis
19.
China Economic Review ; : 101691, 2021.
Article in English | ScienceDirect | ID: covidwho-1385259

ABSTRACT

This paper examines the effect of online learning time on graduating students' test scores in a senior high school. Decisions regarding online education, including those related to participation and learning hours, are endogenous due to both reverse causality and omitted variables. This paper is the result of the natural experiment of the outbreak of COVID-19, which made every student to participate in online education when the spring semester began. In addition, this paper uses a value-added model controlling for the scores that preceded online education, which is a sufficient statistic of students' unobserved ability and motivation. If this cannot completely eliminate the endogeneity problem, it should be able to largely alleviate the problem. The results indicate that: online education has positive but limited impacts on test scores on average, particularly those in the subject of math within the natural sciences track;top-tier students are most positively affected by online education;and the benefits of online education vary among students with different backgrounds. The quantile regression suggests that a 10% increase in online education time raises math test scores by more than 0.25 for the students between the 0.60th and 0.80th quantiles. Surprisingly, it is evident that online learning time has a significant negative effect for some students in certain subjects. Finally, online education neither widens nor narrows the inequality of students' test scores.

20.
Emerg Infect Dis ; 27(11): 2786-2794, 2021 11.
Article in English | MEDLINE | ID: covidwho-1381376

ABSTRACT

We aimed to generate an unbiased estimate of the incidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in 4 urban counties in Utah, USA. We used a multistage sampling design to randomly select community-representative participants >12 years of age. During May 4-June 30, 2020, we collected serum samples and survey responses from 8,108 persons belonging to 5,125 households. We used a qualitative chemiluminescent microparticle immunoassay to detect SARS-CoV-2 IgG in serum samples. We estimated the overall seroprevalence to be 0.8%. The estimated seroprevalence-to-case count ratio was 2.5, corresponding to a detection fraction of 40%. Only 0.2% of participants from whom we collected nasopharyngeal swab samples had SARS-CoV-2-positive reverse transcription PCR results. SARS-CoV-2 antibody prevalence during the study was low, and prevalence of PCR-positive cases was even lower. The comparatively high SARS-CoV-2 detection rate (40%) demonstrates the effectiveness of Utah's testing strategy and public health response.


Subject(s)
COVID-19 , SARS-CoV-2 , Antibodies, Viral , Humans , Probability , Seroepidemiologic Studies , Utah/epidemiology
SELECTION OF CITATIONS
SEARCH DETAIL
...