ABSTRACT
Objective: To analyze the vaccination status of SARS-CoV-2 in children, and explore the relationship between SARS-CoV-2 vaccination and COVID-19 in children. Methods: A retrospective study was conducted to analyze the clinical data of 335 cases of SARS-CoV-2 Omicron variant infection from February 15, 2022 to March 18, 2022 in Shenzhen Third People's Hospital. Results: Among 335 children with SARS-CoV-2 infection, 174(51.9%) cases were vaccinated with the SARS-CoV-2 vaccine;33(31.4%) cases were vaccinated in the 3-<6 years old group;141(61.3%) cases were vaccinated in the 6-<14 years old group. There was a statistically significant difference in the proportion of SARS-CoV-2 vaccination between the 6-<14 years old group and the 3-<6 years old group (X2=26.1, P < 0.05). In the study cohort, 3-<6 years old group and 6-<14 years old group, there was no significant difference in the incidence of COVID-19 in the vaccinated group compared with the unvaccinated group (P > 0.05). In the study cohort, the proportion of confirmed cases of 1 dose of SARS-CoV-2 vaccine and 2 doses or more of SARS-CoV-2 vaccine was 89.5% (68 cases) and 77.6% (76 cases), respectively;in the 6~<14 years old group, the proportion of confirmed cases of 1 dose of SARS-CoV-2 vaccine and 2 doses or more of SARS-CoV-2 vaccine was 90.0% (54 cases) and 76.5% (62 cases), respectively;the differences were statistically significant (X2=4.264, P < 0.05;X2=4.279, P < 0.05). The IgG levels of 18.28 (6.61, 55.2) AU/mL and 58.3 (25.85, 131.41) AU/mL in the study cohort who were vaccinated for 1 dose, 2 doses and more, respectively;the IgG levels of 20.13 (8.33, 44.33) AU/mL and 56.57 (25.85, 150.07) AU/mL in the 6~<14 years old group who were vaccinated for 1 dose, 2 doses and more, respectively;and the differences were statistically significant (Z=-4.37, P < 0.05;Z=-3.96, P < 0.05). Conclusions: Children who received 2 doses of SARS-CoV-2 vaccine have a lower incidence of COVID-19 and higher levels of SARS-CoV-2 antibodies compared with who received 1 dose. It is recommended that children are advised to be vaccinated against the COVID-19.
ABSTRACT
Based on the spatial-temporal perspective of geography, this paper quantitatively measures the impact of COVID-19 on the spatial-temporal pattern of tourism network attention in Zhangjiajie, and finally summarizes the influencing factors and mechanisms. The results show as follows. (1) From the perspective of time, the online attention of tourism in Zhangjiajie shows a trend of "decline to rebound, and to stability", which reflects the temporal mobility of the effect of COVID-19 on the tourism. (2) From the spatial dimension, the scale-order of attention to the Zhangjiajie' s tourism network is relatively stable, and the effect of COVID-19 on the tourism shows a trend of "distance decay" on the whole. (3) The adjustment of tourists' perception of tourism risk, destination familiarity and location, tourists' risk tolerance and authority restriction are the influencing factors of tourism net-work attention. These factors interact with each other to drive the spatio-temporal change of tourism network attention.
ABSTRACT
In this study, we theoretically propose a surface plasmon resonance (SPR) biosensor composed of a plasmonic gold film, double negative (DNG) metamaterial, graphene-MoS2-COOH Van der Waals heterostructures and gold nanoparticles (Au NPs). We use a novel scheme of Goos-Hanchen (GH) shift to study the biosensing performances of our proposed plasmonic biosensor. The calculation results show that, both an extreme low reflectivity of 8.52x10(-10) and significantly enhanced GH sensitivity of 2.1530x10(7) mu m/RIU can be obtained, corresponding to the optimal configuration: 32 nm Au film/120 nm metamaterial/4-layer graphene/4-layer MoS2-COOH. In addition, there is a theoretically excellent linear response between the concentration of target analytes (SARS-CoV-2 and S protein) and the change in differential GH shift. Our proposed biosensor promises to be a useful tool for performing the novel coronavirus detection.
ABSTRACT
OBJECTIVE: To analyze the role of nosocomial infection informatics surveillance system in the prevention and control of multidrug-resistant organisms(MDROs) infections. METHODS: The First Affiliated Hospital of Guangdong Pharmaceutical University was selected as the study subjects, which had adopted the nosocomial infection informatics surveillance system since Jan.2020. The period of Jan.to Dec.2020 were regarded as the study period, and Jan.to Dec.2019 were regarded as the control period. The situation of nosocomial infection and MDROs infections in the two periods were retrospectively analyzed. RESULTS: The incidence of nosocomial infections and underreporting of nosocomial infection cases in this hospital during the study period were 2.52%(1 325/52 624) and 1.74%(23/1 325), respectively, and the incidences of ventilator associated pneumonia(VAP), catheter related bloodstream infection(CRBSI), catheter related urinary tract infection(CAUTI)were 4.10(31/7 568), 2.11(14/6 634), and 2.50(25/9 993) respectively, which were lower than those during the control period(P< 0.05). The positive rate of pathogenic examination in the hospital during the study period was 77.95%(1 269/1 628), which was higher than that during the control period(P<0.05), the overall detection rate of MDROs was 15.77%(206/1 306), the detection rates of MDROs in Escherichia coli, Acinetobacter baumannii, Klebsiella pneumoniae, Staphylococcus epidermidis, Pseudomonas aeruginosa and Staphylococcus aureus were lower than those during the control period(P<0.05). CONCLUSION: The development and application of the informatics technology-based surveillance system of nosocomial infection could effectively reduce the incidence of nosocomial infections and device related infections, decrease the under-reporting of infection cases, and also reduce the detection rate of MDROs as well as the proportion of MDROs detected in common pathogenic species.
ABSTRACT
The COVID-19 vaccines provide a high degree of protection against severe disease, hospitalisation, and death. However, no vaccine claimed 100% effectiveness and it is expected that a small proportion of vaccinated individuals may develop a breakthrough infection due to individual differences, virus variants and other factors. We conducted an epidemiological investigation and analysis of an imported case who had finished four doses of vaccination, and in order to provide a relevant reference for regular epidemic prevention and control in the post-pandemic era.
ABSTRACT
Objective: To explore the pathogen composition and distribution characteristics of pathogens in respiratory samples from patients with fever of unknown origin. Methods: A total of 96 respiratory samples of patients with unknown cause fever with respiratory symptoms were collected from four hospitals above grade II in Shijiazhuang area (Hebei Provincial Hospital of Traditional Chinese Medicine, Luancheng District People's Hospital, Luquan District People's Hospital, Shenze County Hospital) from January to April 2020, and multiplex-fluorescent polymerase chain reaction(PCR)was used to detect influenza A virus, influenza B virus, enterovirus, parainfluenza virus I/II/III/IV, respiratory adenovirus, human metapneumovirus, respiratory syncytial virus, human rhinovirus, human bocavirus, COVID-19, Mycoplasma pneumoniae, Chlamydia pneumoniae, Legionella pneumophila, Pseudomonas aeruginosa, Streptococcus pneumoniae, Klebsiella pneumoniae, Group A streptococcus, Haemophilus influenzae, Staphylococcus aureus nucleic acid detection, the results were analyzed for chi-square. Results: A total of 8 pathogens were detected in the upper respiratory tract samples of 96 fever patients, including 1 kind of virus, 6 kinds of bacterias, and Mycoplasma pneumoniae. There were 12 viruses including influenza virus and parainfluenza virus, Legionella pneumophila and Chlamydia pneumoniae were not detected. The pathogen detection rates in descending order were Streptococcus pneumoniae (58/96, 60.42%), Haemophilus influenzae(38/96, 39.58%), Klebsiella pneumoniae (14/96, 14.58%), Staphylococcus aureus (10/96, 10.42%), Mycoplasma pneumoniae (8/96, 8.33%), Pseudomonas aeruginosa (6/96, 6.25%), Group A streptococcus (4/96, 4.17%) and human rhinovirus (2/96, 2.08%). The proportions of single-pathogen infection and multi-pathogen mixed infection in fever clinic patients were similar, 41.67% (40/96) and 45.83% (44/96), respectively, and 12.50% (12/96)of the cases had no pathogens detected. The infection rate of Mycoplasma pneumoniae in female patients with fever (21.43%) was higher than that in male patients with fever (2.94%) (P < 0.05). There was no statistical difference between the distribution of of other pathogens and gender and age(P > 0.05). Conclusions: The upper respiratory tract pathogens were mainly bacterial infections, and occasional human rhinovirus and Mycoplasma pneumonia infections. In clinical diagnosis and treatment, comprehensive consideration should be given to the pathogen detection.
ABSTRACT
This paper aims to analyze the research on the current situation of water-saving agriculture development in Europe. Water-saving agriculture in Europe started early, governments and farmers in various countries have a strong awareness of water-saving in agriculture and have achieved certain results. Due to the global spread of the COVID-19 pandemic, the lack of up-to-date field research, the complexity of various agricultural disciplines and categories, and the lack of information sharing, the current cognition of recent progress in the development of water-saving agriculture in Europe is not comprehensive enough. This paper selects four representative European countries: Spain, Germany, Italy, and Denmark as the research objects. Based on the existing research of Chinese and Western scholars, this paper analyzes and studies the current situation of water-saving agriculture in Europe. It has far-reaching significance for other countries in the world to have further development in water-saving agriculture and to protect water resources.
ABSTRACT
Objective: To understand the influence of junior middle school students' health literacy on knowledge, belief and behavior of COVID-19 in rural areas of Jiangxi Province, and to enhance junior middle school students' ability to deal with public health emergencies. Methods: Stratified cluster random sampling was used to investigate the health literacy, knowledge level and behavior of COVID-19 protection of 4 311 grade 7 to grade 8 students in rural areas of Jiangxi Province;Chi-square test and Logistic regression analysis were used to analyze the correlation between junior high school students' health literacy and COVID-19 protection knowledge, belief and behavior. Results: The rate of health literacy of junior middle school students in rural areas was 18.21%(n=785), the reported rate of intermediate level was high (n=2 454, 56.92%), and the reported rate of junior high school students at a low level of health literacy was 24.87%(n=1 072). The rate of junior middle school students in rural areas with good COVID-19 protection knowledge was 63.49%, the rate of positive protection attitude was 74.25%, and the rate of good protection behavior was 85.36%;Rate of COVID-19 protection knowledge (OR=4.85, 95%CI=3.80-6.18) and positive rate of protection attitude of high-level health literacy (OR=44.07, 95%CI=24.57-79.05), protective behavior possession rate (OR=25.99, 95%CI=19.67-34.35) were higher than those with low level of health literacy(P < 0.01). Conclusion: Health literacy is associated with COVID-19 protection knowledge, belief and behavior in rural junior high school students of Jiangxi Province, the findings provide direction for junior middle school students to improve their ability to deal with public health emergencies.
ABSTRACT
Affective computing (AC) has been regarded as a relevant approach to identifying online learners' mental states and predicting their learning performance. Previous research mainly used one single-source data set, typically learners' facial expression, to compute learners' affection. However, a single facial expression may represent different affections in various head poses. This study proposed a dual-source data approach to solve the problem. Facial expression and head pose are two typical data sources that can be captured from online learning videos. The current study collected a dual-source data set of facial expressions and head poses from an online learning class in a middle school. A deep learning neural network using AlexNet with an attention mechanism was developed to verify the syncretic effect on affective computing of the proposed dual-source fusion strategy. The results show that the dual-source fusion approach significantly outperforms the single-source approach based on the AC recognition accuracy between the two approaches (dual-source approach using Attention-AlexNet model 80.96%;single-source approach, facial expression 76.65% and head pose 64.34%). This study contributes to the theoretical construction of the dual-source data fusion approach, and the empirical validation of the effect of the Attention-AlexNet neural network approach on affective computing in online learning contexts.
ABSTRACT
Aim: Although most patients with COVID-19 experience respiratory tract infections, severe reactions to the virus may cause coagulation abnormalities that mimic other systemic coagulopathies associated with severe infections, such as disseminated intravascular coagulation and thrombotic microangiopathy. Fluctuations in platelet markers, which are an indicator of the acute phase response for COVID-19, are of clinical importance. The aim of this study is to evaluate the relationship between disease severity and Platelet Mass Index (MPI) parameters in COVID-19 patients. Material(s) and Method(s): This retrospective observational study was conducted with patients who were diagnosed with COVID-19 in a tertiary hospital. The study was continued with the remaining 280 patients. All laboratory data were scanned retrospectively from patient files and hospital information system. Result(s): A very high positive correlation was found between PMI and PLT. The PMI value in women was significantly higher than in men. It was observed that PMI did not differ significantly in terms of mortality, intubation, CPAP and comorbidity. PMI vs. Pneumonia Ct Severity Score, biochemistry parameters (AST, CRP), hemogram parameters (WBC, HGB, HCT, MCV, LYM, MPV EO) and coagulation factors (aPTT and FIB) at various levels of positive/negative, weak and strong, and significant relationship was found. There was no significant relationship between hormone and D-dimer when compared with PMI. Discussion(s): Although platelet count alone does not provide information about the prognosis of the disease, PMI may guide the clinician as an indicator of lung damage in seriously ill patients.Copyright © 2022, Derman Medical Publishing. All rights reserved.
ABSTRACT
COVID-19 has had serious consequences in all areas of social life, including education. In this period, distance education appeared as an inevitable solution. Even today, when the pandemic process is over and re-normalization has begun, online teaching environments have become such an indispensable part of education systems that it has been decided that a certain proportion of the courses will be conducted online in universities. For this reason, determining student experiences in online courses is important in planning the future of distance education. Since academic performance is the output of the teaching process, students' academic performance is one of the topics of interest in higher education research. There may be different factors affecting the academic performance of students in the distance education process, which imposes more responsibility on students and requires self-control. This study aimed to examine the relationship of academic performance in the distance education with home infrastructure, student interaction, computer skills, academic satisfaction. This research is based on a large-scale study, "The impact of the COVID-19 pandemic on the lives of higher education students", examining the pandemic's impact on higher education student perceptions in 2020. It has been observed that home infrastructure has a significant impact on the student's academic performance. The infrastructure increases the interaction of the student. When home infrastructure is taken as a control variable, students' computer skills are the highest predictor of their perception of academic performance, followed by their online interactions and, finally, perceived satisfaction. Today, pandemic conditions are still ongoing. In addition, even as the pandemic ends, online education has become an indispensable part of our education system. Therefore, the findings of the research would be beneficial for the ongoing planning process.
ABSTRACT
Objective: To analyze and compare the effects of different clinical characteristics on the negative conversion time of nucleic acid detection after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant infection, and to provide a scientific basis for the isolation and treatment of coronavirus disease 2019 (COVID-19). Methods: The epidemiological and clinical data of 228 mild SARS-CoV-2 Omicron variant infected patients diagnosed in Shanghai were retrospectively collected from April 27, 2022 to June 8, 2022 in Wujiaochang designated Hospital, Yangpu District, Shanghai. The negative conversion time of nucleic acid detection was used as the outcome variable, and the patients were divided into A (18 days) and B (>18 days). Univariate and multivariate logistic regression analysis were used to analyze the influencing factors of the negative conversion time of nucleic acid detection. Results: The mean nucleic acid conversion time of 228 patients was (18.7+or-12.1) d, with the median time of 18 (2-46) d. Among them, 120 patients in group A had an average nucleic acid conversion time of (13.2+or-2.0) d, and 108 cases in group B had an average nucleic acid conversion time of (20.8+or-1.3) d. Univariate analysis showed that there were no statistically significant differences in the effects of hypertension, coronary heart disease, diabetes, hypokalemia, malignant tumors, neuropsychiatric diseases, chronic digestive diseases on the negative nucleic acid conversion time (P > 0.05);however, there were significant differences in the effects of combined cerebrovascular disease, leukopenia, chronic respiratory system diseases and vaccination on the negative nucleic acid conversion time (P < 0.05). Further multivariate logistic regression analysis revealed that the combination of chronic respiratory diseases and non-vaccination were significant risk factors for prolongation of negative nucleic acid conversion time (P < 0.05). Conclusions: The results of this study show that gender, age and whether hypertension, coronary heart disease, diabetes mellitus, hypokalemia, malignant tumor, neuropsychiatric disease and chronic digestive disease have no significant effect on the nucleic acid conversion time, whereas chronic respiratory disease and no vaccination are significantly correlated with the prolongation of nucleic acid conversion time in SARS-CoV-2 Omicron-infected patients.
ABSTRACT
Objective: This study focused on the systematic literature measurement and visual analysis of treating COVID-19 with combined Chinese and Western medicine to explore the development status, research hot spots and trends, and cutting-edge dynamics. It provides data, information support, and development references for treating COVID-19with combined Chinese and Western medicine. Methods: Three major databases of China National Knowledge Infrastructure(CNKI), Wanfang Data, and China Science and Technology Journal Database were used as data sources to retrieve the relevant literature on the combined Chinese and Western medicine for the treatment of COVID-19 from March2019 to March 2022. Statistical analysis was performed using bibliometric methods and CiteSpace software. Visual analysis was performed on publishing trends, research institution cooperation, author cooperation, keyword co-occurrence and clustering, and research hotspots. Results: A total of 476 articles were included in this study, with the largest number published in 2020. Statistical analysis of published units showed that the cooperative relationship between institutions was discrete, indicating that the research on treating novel coronavirus with combined Chinese and western medicine was extensive. Hot spots in the research were mainly reflected in four aspects:coronavirus, diagnosis and treatment plan, combined Chinese and Western medicine, and epidemic prevention and control. Conclusion: The research theme of treating COVID-19 with combined Chinese and Western medicine dynamically changes with the epidemic development, which is guided by clinical efficacy. It mainly focuses on the formulation of diagnosis and treatment plans. The cooperation between authors and institutions is insufficient, and communication needs to be further strengthened.
ABSTRACT
This research aims to grasp the evolution of consumer demand and improve the resilience of the hotel industry under the public health crisis (COVID-19). Online reviews of 7,679 hotels in 10 cities were collected from Ctrip, China's major online hotel platform. Then, we applied opinion mining and time evolution to mine the change in consumer demand before, during, and after the COVID-19 pandemic. Findings show that some consumer demands (e.g. epidemic safety) will change during the outbreak period. However, during the nonoutbreak period, users were more concerned about their own check-in experience (e.g. hotel facilities, front desk services). This article provides new ideas for identifying the dynamic value of online reviews. We suggest that businesses focus on ensuring hotel safety during the crisis period. The results contribute essential theoretical and practical significance to the hotel industry's crisis management during public health crises.
ABSTRACT
Rapid and continuous changes in digital technologies have changed both classroom practices and teacher profiles in education. It can be argued that a new context of teaching may lead some teachers to develop a different teacher identity in order to meet the needs of the era. Within this perspective, this case study attempts to explore the impacts of Information and Communication Technologies (ICT) revolution in education on teachers' professional identity through the lens of three English instructors from three different contexts in Turkey. The study particularly focuses on reflections of teachers during the pandemic. As a theoretical framework, the study adopts Wenger's (1997) social theory of learning and, within this framework, it discusses these teachers' professional identities in relation to their ICT usage. In particular, three modes of belonging, Engagement, Imagination and Alignment, are underlined. A qualitative approach is employed based on the written history documents of the participants and semi-structured interviews as data collection tools. The findings are gathered with a deductive thematic analysis, and they illustrate that teachers have some external and internal difficulties regarding their ICT usage, and they form a new shape of professional identity mainly through collaboration, community expertise and contributing new ideas in their school contexts. Although the use of new digital technologies mostly enables them to adopt a positive and modern teacher identity in their teaching contexts, it also leads some of them to sometimes question their teacher identity due to their limited ICT knowledge and competence. Thus, the study suggests some implications both for language teachers to invest in their digital identities, and for school administrations to create a friendly atmosphere where the community of expertise can be shared freely among teachers.
ABSTRACT
While technology factors are the main driver of the booming real estate APP platforms with important implications for user behavior pattern during and post-pandemic contexts, there is a lack of adequate research. In response, this study explores the user behavior pattern of real estate APP platforms to promote user mental health by taking the real estate APP platforms users as the participants based on theory of technology readiness and acceptance model. Data collected from offline surveys are analyzed using PLS-SEM. The results reveal the technology readiness index positively affects individuals' perceived usefulness and satisfaction, ultimately positively affects individuals' continuance intention with real estate APP platforms;satisfaction with real estate APP platforms mediated the relationship between technology readiness index, perceived ease of use, perceived usefulness, and individuals' continuance intention with real estate APP platforms. However, the group comparison finds no significant difference in user behavior patterns by gender. The contribution of this study is to reveal the influence mechanisms of digital technology on users' behavioral patterns toward real estate APP platforms, which can help guide the sustainable development of real estate APP platforms and promote user mental health and wellbeing in the post-COVID era.
ABSTRACT
Many zoonotic diseases are found in wild animals and present a serious risk to human health, in particularly the virus carried by birds flying freely around the world is hard to control. There are three main bird migration routes which cover the most areas of China. It is important to investigate and fully understand the types of avian transmitted diseases in key areas on the bird migration routines and its impacts on both birds and human health. However, no literature is available in how about the risk of virus carried by migrating birds, and how to predict and reduce this risk of virus spreading to human being so far. In this paper, we first reviewed the main pathogen types carried by birds, including coronaviruses, influenza viruses, parasites, Newcastle disease virus (NDV), etc., and then discussed the spread risk of avian viruses to human being and animals in key areas of biosafety prevention. We also analyzed and discussed the risk of cross-spread of diseases among different bird species in nature reserves located on bird migration routes which provide sufficient food sources for migratory birds and attract numerous birds. Diseases transmitted by wild birds pose a serious threat to poultry farms, where high density of poultry may become avian influenza virus (AIV) reservoirs, cause a risk of avian influenza outbreaks. Airports are mostly built in suburban areas or remote areas with good ecological environment. There are important transit places for bird migration and densely populated areas, which have serious risk of disease transmission. Finally, this paper puts forward the following prevention suggestions from three aspects. First, establish and improve the monitoring and prediction mechanism of migratory birds, and use laser technology to prevent contact between wild birds and poultry. Second, examine and identify virus types carried by birds in their habitats and carry out vaccination. Third, protect the ecological environment of bird habitat, and keep wild birds in their natural habitat, so as to reduce the contact between wild birds and human and poultry, and thus reduce the risk of virus transmission.
ABSTRACT
Introduction: Patients' negligence and difficult access to healthcare have an impact on the worsening of emergency conditions, which require immediate treatment due to the possibility of exacerbation in a short period of time. Untreated intra- and extraoral abscesses can have serious consequences on the patient's health and in many cases are life-threatening conditions increasing risk of respiratory obstruction, thrombophlebitis, meningitis, mediastinitis and septicemia. Background: The aim of this study is to investigate the impact of the pandemic and the resulting impediments to accessing medical care on the incidence and type of emergencies in the Oral Surgery Department. Material and methods: This was a retrospective study of 85375 patients aged 2 months to 90 years old with diagnosed intra- and extraoral abscesses before COVID-19 pandemic (2018,2019), and during pandemic (2020, 2021) in the Department of Oral Surgery of the Medical University in Lublin. The obtained results were statistically analyzed with the use of a computer program. Conclusions: The fewest patients were admitted in 2020, and the most in 2021, where we can already see the effects of the pandemic. Emergencies occurred most frequently in people aged 21-30, then 31-40. In 365 cases, tooth extraction was performed, and only in 28 cases, root canal treatment was attempted. Conclusions. Oral health service provision has been significantly affected by COVID-19. Patients came to their appointments too late, which in most cases resulted in the necessity of tooth extraction without attempting root canal treatment.
ABSTRACT
Teaching during a global pandemic has prompted many discussions about how faculty can best support students and create classrooms where deep learning and engagement occur. In this conversation, we argue there is a role for empathy in college classrooms. We present data from interviews with faculty at a small, Midwestern, teaching-focused university during the fall of 2020. We map these perspectives onto the empathy paths framework and suggest that the therapeutic and instrumental paths are most useful for understanding empathy in the classroom. We also discuss why it is important for faculty to think about empathy and the role sociology can play in these conversations. Finally, we present a series of empathetic practices individual faculty can incorporate into their pedagogy and structural supports that departments and universities can provide to help faculty engage in empathetic practices in the classroom.
ABSTRACT
Background. Since the start of the COVID-19 pandemic, Chad has had 7,417 confirmed cases and 193 deaths, one of the lowest in Africa. Objective. This study assessed SARS-CoV-2 immunity in N'Djamena. Methods. In August-October 2021, eleven N'Djamena hospitals collected outpatient data and samples. IgG antibodies against SARSCoV- 2 nucleocapsid protein were identified using ELISA. "Bambino Gesu" Laboratory, Rome, Italy, performed external quality control with chemiluminescence assay. Results. 25-34-year-old (35.2%) made up the largest age group at 31.9 12.6 years. 56.4% were women, 1.3 women/men. The 7th district had 22.5% and the 1st 22.3%. Housewives and students dominated. Overall seroprevalence was 69.5% (95% CI: 67.7-71.3), females 68.2% (65.8-70.5) and males 71.2% (68.6-73.8). >44-year-old had 73.9% seroprevalence. Under-15s were 57.4% positive. Housewives (70.9%), civil servants (71.5%), and health workers (9.7%) had the highest antibody positivity. N'Djamena's 9th district had 73.1% optimism and the 3rd district had 52.5%. Seroprevalences were highest at Good Samaritan Hospital (75.4%) and National General Referral Hospital (74.7%). Conclusion. Our findings indicate a high circulation of SARS-CoV- 2 in N'Djamena, despite low mortality and morbidity after the first two COVID-19 pandemic waves. This high seroprevalence must be considered in Chad's vaccine policy.