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It is crucial to investigate adaptability in the context of COVID-19, as evidence suggests that difficulties posed by adaptability can be exacerbated during times of crisis. International students encounter additional pressures during this period, which might impair their capacity to stay and prosper in a new place. In light of this context, the purpose of this study is to examine the factors that contribute to the adaptability of international university students in Malaysia, namely the academic system, acculturation, and social support. A cross-sectional research design was used, and the research instruments were adapted from a number of previous studies. A total of one hundred thirty online questionnaires were filled out by international students in Malaysia. The research hypotheses were evaluated using SPSS Version 27.0. All predictors were found to have a statistically significant and positive effect on the adaptability of international students. This research aims to shed light on educational management strategies for addressing the adaptability challenges faced by most international students within COVID-19 by illuminating the key drivers that influence adaptability. © Journal of Curriculum and Teaching..All rights reserved
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Accurate and effective container throughput forecasting plays an essential role in economic dispatch and port operations, especially in the complex and uncertain context of the global Covid-19 pandemic. In light of this, this research proposes an effective multi-step ahead forecasting model called EWT-TCN-KMSE. Specifically, we initially use the empirical wavelet transform (EWT) to decompose the original container throughput series into multiple components with varying frequencies. Subsequently, the state-of-the-art temporal convolutional network is utilized to predict the decomposed components individually, during which an improved loss function that combines mean square error (MSE) and kernel trick is employed. Eventually, the deduced prediction results can be obtained by integrating the predicted values of each component. In particular, this research introduces the MIMO (multi-input and multi-output) strategy to conduct multi-step ahead container throughput forecasting. Based on the experiments in Shanghai port and Ningbo-Zhoushan port, it can be found that the proposed model shows its superiority over benchmark models in terms of accuracy, stability, and significance in container throughput forecasting. Therefore, our proposed model can assist port operators in their daily management and decision making. © 2023 John Wiley & Sons Ltd.
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In response to the current problem of highly contagious new coronavirus and repeated epidemics, which cause great threat and inconvenience to people's production and life, In this paper, a multifunctional intelligent epidemic prevention robot control system based on a single chip microcomputer is designed to realize the intelligent management of community epidemic prevention and control. Stm32 microcontroller is used as the control core. In order to improve the efficiency of prevention and control management and reduce contact, the Jetson Nano controller is designed to provide map reproduction, positioning navigation, and path planning functions. It is used to summarize patient status information quickly and efficiently, the design provides face recognition and remote monitoring functions to realize real-time uploading of accurate data to cell phone console APP and computer terminal integrated monitoring platform. Through the map reconstruction and positioning simulation test, an optimal path is selected to ensure the stable movement of the epidemic prevention robot. The face_recognition algorithm's error reception rate, error rejection rate, and accuracy rate are 0.35%, 11.12%, and 88.53%, respectively, which are better than the face-net algorithm in three aspects and can well meet the needs of small communities. The face recognition needs of small community areas can be well met. This epidemic prevention and control system can realize efficient community epidemic prevention and control management, reduce contact transmission, and lower the difficulty of epidemic prevention and control. © 2022 IEEE.
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In epidemic prevention and control measures, unmanned devices based on autonomous driving technology have stepped into the front lines of epidemic prevention, playing a vital role in epidemic prevention measures such as protective measures detection. Autonomous positioning technology is one of the key technologies of autonomous driving. The realization of high-precision positioning can provide accurate location epidemic prevention services and a refined intelligent management system for the government and citizens. In this paper, we propose an unmanned vehicle (UV) positioning system REW_SLAM based on lidar and stereo camera, which realize real-time online pose estimation of UV by using high-precision lidar pose correction visual positioning data. A six-element extended Kalman filter (6-element EKF) is proposed to fusion lidar and stereo camera sensors information, which retains the second-order Taylor series of observation and state equation, and effectively improves the accuracy of data fusion. Meanwhile, considering improving lidar outputs quality, a modified wavelet denoising method is introduced to preprocess the original data of lidar. Our approach was tested on KITTI datasets and real UV platform, respectively. By comparing with the other two algorithms, the relative pose error and absolute trajectory error of this algorithm are increased by 0.26 m and 2.36 m on average, respectively, while the CPU occupancy rate is increased by 6.685% on average, thereby proving the robustness and effectiveness of the algorithm.
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This paper assesses the potential risks of epidemic situation and public opinion during the Beijing Winter Olympic Games by analyzing the epidemic situation and public opinion of the Tokyo Olympic Games. The results show that there is a strong time-lag correlation between the COVID-19 epidemic and the public opinion of the Tokyo Olympics. For the epidemic situation, the multi-agent modeling method is used at the city level to simulate the possible spread of diseases in the city where the event was held. At the Olympic village level, the modified the SEIR transmission model is modified to simulate the virus transmission in the Olympic Village during the Beijing Winter Olympic Games. At the end, the risk analysis of the Beijing Winter Olympic Games is carried out based on the time series prediction model. © 2022, Editorial Board of Journal of the University of Electronic Science and Technology of China. All right reserved.
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Since the emergence of coronavirus disease 2019 (COVID-19), this highly contagious disease has ravaged the world, cumulatively causing millions of deaths and huge economic losses. As the culprit of COVID-19, severe acute respiratory syndrome beta-coronavirus 2 (SARS-CoV-2) is highly infectious and pathogenic, which has caused extreme panic worldwide. Early and rapid monitoring of SARS-CoV-2 has a significant role in suppressing the pandemic and reducing the virus's lethality. In our work, we prepared a self-enhanced ruthenium complex linked to zeolitic imidazole framework-8 (ZIF-8) and used it as an electrochemiluminescence (ECL) emitter. Additionally, a double-stranded specific nuclease (DSN)-assisted target RNA cycling with catalytic hairpin assembly (CHA) signal amplification technology was used to achieve the conversion of target RNA concentration to double-stranded DNA (dsDNA) output which significantly improved the detection sensitivity of target RNA under environmental conditions and in real human serum samples. In addition, we also combined the trans-cleavage property of CRISPR-Cas12a with the adsorption property of C3N4 on a ferrocene (Fc)-labeled DNA probe and obtained target RNA-dependent ECL signals. The reliable detection protocol achieved the transformation of SARS-CoV-2 RNA concentration to ECL responses, obtaining a limit of detection (LOD) of 0.67 fM with high specificity and reproducibility, which was of guiding significance for current detection methods of mutant SARS-CoV-2 and universal RNA.
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The prediction of bus passenger volume is the fundamental research content of bus transfer optimization. In order to get more accurate passenger volume data and improve the utilization efficiency of urban traffic resources, according to randomness, time-varying and uncertainty of public transport passenger volume in Beijing, combined with the current new coronavirus pneumonia epidemic, this paper collected the relevant data of Beijing in the past 40 years, and predicted and analyzed them from four dimensions of public transport, urban scale and residents' economic level, taxi and sudden health events by BP neural network and regression analysis. The results show that BP neural network has good prediction results, and BP neural network is suitable for large sample size, which needs to fit or predict complex nonlinear relationships. © 2021 SPIE
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Artificial Intelligence (AI) is an interdisciplinary subject developed on the basis of computer technology, cybernetics, mathematics, philosophy and brain science. The purpose of AI is to study new ways to extend the intelligence of human brain in various fields. In recent years, the rapid development of AI technology has brought innovation to medical science and health care. During the pandemic of coronavirus disease 2019 (COVID‑19) AI has been widely used in epidemiological investigation and outbreak prediction, clinical diagnosis and treatment, hospital management, research and development of new drugs and vaccines. The application of AI has reduced the clinical workload and the consumption of medical resources, greatly assisted the battle against COVID‑19. This article introduces the progresses on the applications of AI technology to provide information for its further application in the fighting against COVID‑19. © 2022 Chinese Medical Journals Publishing House Co.Ltd.
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Having analyzed various datasets, including the 4 million observations of industrial firms, we describe the recent evolution of corporate debt in the People’s Republic of China (PRC). Unlike in the United States, the rising total debt-to-GDP ratio in the PRC since 2008 has been driven mainly by the nonfinancial corporate sector. More importantly, we find that corporate debt in the PRC is highly “structural, " with much of it concentrated in a small fraction of firms, mostly large, state-owned, and listed, while the majority of the other firms have deleveraged continuously over the decade. Remarkably, the implementation of supply-side structural reform in the PRC since 2015 has led to reduced debt ratios and improved the performance of state-owned enterprises (SOEs). Meanwhile, COVID-19 had a limited impact on deleveraging. Deepening capital market reforms to increase the firms’ share of direct market financing and accelerating SOE reforms are essential to alleviate corporate debt risk in the PRC. © Asian Development Bank 2022.
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BackgroundSARS-CoV-2 Omicron variant BA.1 first emerged on the Chinese mainland in January 2022 in Tianjin and caused a large wave of infections. During mass PCR testing, a total of 430 cases infected with Omicron were recorded between January 8 and February 7, 2022, with no new infections detected for the following 16 days. Most patients had been vaccinated with SARS-CoV-2 inactivated vaccines. The disease profile associated with BA.1 infection, especially after vaccination with inactivated vaccines, is unclear. Whether BA.1 breakthrough infection after receiving inactivated vaccine could create a strong enough humoral immunity barrier against Omicron is not yet investigated. MethodsWe collected the clinical information and vaccination history of the 430 COVID-19 patients infected with Omicron BA.1. Re-positive cases and inflammation markers were monitored during the patients convalescence phase. Ordered multiclass logistic regression model was used to identify risk factors for COVID-19 disease severity. Authentic virus neutralization assays against SARS-CoV-2 wildtype, Beta and Omicron BA.1 were conducted to examine the plasma neutralizing titers induced after post-vaccination Omicron BA.1 infection, and were compared to a group of uninfected healthy individuals who were selected to have a matched vaccination profile. FindingsAmong the 430 patients, 316 (73.5%) were adults with a median age of 47 years, and 114 (26.5%) were under-age with a median age of 10 years. Female and male patients account for 55.6% and 44.4%, respectively. Most of the patients presented with mild (47.7%) to moderate diseases (50.2%), with only 2 severe cases (0.5%) and 7 (1.6%) asymptomatic infections. No death was recorded. 341 (79.3%) of the 430 patients received inactivated vaccines (54.3% BBIBP-CorV vs. 45.5% CoronaVac), 49 (11.4%) received adenovirus-vectored vaccines (Ad5-nCoV), 2 (0.5%) received recombinant protein subunit vaccines (ZF2001), and 38 (8.8%) received no vaccination. No vaccination is associated with a substantially higher ICU admission rate among Omicron BA.1 infected patients (2.0% for vaccinated patients vs. 23.7% for unvaccinated patients, P<0.001). Compared with adults, child patients presented with less severe illness (82.5% mild cases for children vs. 35.1% for adults, P<0.001), no ICU admission, fewer comorbidities (3.5% vs. 53.2%, P<0.001), and less chance of turning re-positive on nucleic acid tests (12.3% vs. 22.5%, P=0.019). For adult patients, compared with no prior vaccination, receiving 3 doses of inactivated vaccine was associated with significantly lower risk of severe disease (OR 0.227 [0.065-0.787], P=0.020), less ICU admission (OR 0.023 [0.002-0.214], P=0.001), lower re-positive rate on PCR (OR 0.240 [0.098-0.587], P=0.002), and shorter duration of hospitalization and recovery (OR 0.233 [0.091-0.596], P=0.002). At the beginning of the convalescence phase, patients who had received 3 doses of inactivated vaccine had substantially lower systemic immune-inflammation index (SII) and C-reactive protein than unvaccinated patients, while CD4+/CD8+ ratio, activated Treg cells and Th1/Th2 ratio were higher compared to their 2-dose counterparts, suggesting that receipt of 3 doses of inactivated vaccine could step up inflammation resolution after infection. Plasma neutralization titers against Omicron, Beta, and wildtype significantly increased after breakthrough infection with Omicron. Moderate symptoms were associated with higher plasma neutralization titers than mild symptoms. However, vaccination profiles prior to infection, whether 2 doses versus 3 doses or types of vaccines, had no significant effect on post-infection neutralization titer. Among recipients of 3 doses of CoronaVac, infection with Omicron BA.1 largely increased neutralization titers against Omicron BA.1 (8.7x), Beta (4.5x), and wildtype (2.2x), compared with uninfected healthy individuals who have a matched vaccination profile. InterpretationReceipt of 3-dose inactivated vaccines can substantially reduce the disease severity of Omicron BA.1 infection, with most vaccinated patients presenting with mild to moderate illness. Child patients present with less severe disease than adult patients after infection. Omicron BA.1 convalescents who had received inactivated vaccines showed significantly increased plasma neutralizing antibody titers against Omicron BA.1, Beta, and wildtype SARS-CoV-2 compared with vaccinated healthy individuals. FundingThis research is supported by Changping Laboratory (CPL-1233) and the Emergency Key Program of Guangzhou Laboratory (EKPG21-30-3), sponsored by the Ministry of Science and Technology of the Peoples Republic of China. Research in contextO_ST_ABSEvidence before this studyC_ST_ABSPrevious studies (many of which have not been peer-reviewed) have reported inconsistent findings regarding the effect of inactivated vaccines against the Omicron variant. On Mar 6, 2022, we searched PubMed with the query "(SARS-CoV-2) AND ((Neutralisation) OR (Neutralisation)) AND ((Omicron) OR (BA.1)) AND (inactivated vaccine)", without date or language restrictions. This search identified 18 articles, of which 13 were directly relevant. Notably, the participants in many of these studies have received only one or two doses of inactivated vaccine with heterologous booster vaccination; other studies have a limited number of participants receiving inactivated vaccines. Added value of this studyTo date, this is the first study to report on the protective effect of inactivated vaccines against the severe disease caused by the Omicron variant. We examine and compare the disease profile of adults and children. Furthermore, we estimate the effect of post-vaccination omicron infection on plasma neutralization titers against Omicron and other SARS-COV-2 variants. Specifically, the disease profile of Omicron convalescents who had received two-dose primary series of inactivated vaccines with or without a booster dose prior to infection is compared with unvaccinated patients. We also analyzed the effect of infection on neutralizing activity by comparing vaccinated convalescents with vaccinated healthy individuals with matched vaccination profiles. Implications of all the available evidenceCompared with adults, child patients infected with Omicron tend to present with less severe disease and are less likely to turn re-positive on nucleic acid tests. Receipt of two-dose primary series or three doses of inactivated vaccine is a protective factor against severe disease, ICU admission, re-positive PCR and longer hospitalization. The protection afforded by a booster dose is stronger than two-dose primary series alone. Besides vaccination, infection with Omicron is also a key factor for elevated neutralizing antibody titers, enabling cross-neutralization against Omicron, wildtype (WT) and the Beta variant.
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Infecciones , Dolor Irruptivo , COVID-19 , InflamaciónRESUMEN
Since the outbreak of COVID-19, the pandemic has changed the lives of many people and brought dramatic motional experiences. Among many social media platforms, YouTube saw the most significant growth of any social media app among American users during the pandemic, according to the Pew Research Center on 7th April 2021. Exposure to COVID-19 related news can have a significant impact on user engagement on social networks. Different news may trigger different emotions (i.e., anger, anticipation, disgust, fear, joy, sadness, surprise, or trust), and a user may engage differently in response to the news. On YouTube, user engagement is manifested through actions such as liking, disliking, commenting, or sharing videos. During the pandemic, many users provide constructive comments that are encouraging, respectful, and informative to support each other. We applied sentiment analysis in the study to investigate different emotions and applied semantic analysis to investigate positive appraisal (i.e., encouraging, respectful, and informative) to identify salient factors that can motivate user engagement. The findings of the work shed light on how social network platforms could encourage constructive comments to help people provide emotional support to each other during pandemics through using positive appraisal in online news comments. © 2021 International Consortium for Electronic Business. All rights reserved.
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In March 2020, cities across Canada locked down in an effort to control the rapid spread of the novel coronavirus (SARS-CoV-2). The containment measures forced many disruptive societal changes, with the virtual delivery of medical education being one example. Many of the resulting educational changes will persist for the foreseeable future. As students at the Temerty Faculty of Medicine at the University of Toronto, we have observed first-hand the transition to a virtual curriculum. Preclerkship medical students have been unable to participate in clinical observerships as part of early career exploration throughout the duration of the pandemic. These clinical experiences offer more than just opportunities to narrow career options, they also serve as a critical part of our development as future physicians. Given the continued need to preserve personal protective equipment and comply with physical distancing guidelines, we believe innovative solutions are needed to restore this critical component of our medical education. Our student-led research group has described a novel use of a point-of-view livestreaming technology that allows physicians to demonstrate physical exams while teaching clinical skills to medical students as one possible solution. As the pandemic continues to threaten global health, a clear need exists to identify and implement creative innovations to prepare future physicians.
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In this paper, we present the first idea of using a DNA triple helix structure to inhibit CRISPR-Cas12a activity and apply it to the design of an electrochemiluminescent biosensor for the detection of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA-dependent RNA polymerase (RdRp) gene in real samples and environmental surveillance. We employed a segment from the RdRp gene of SARS-CoV-2 by an entropy-driven reaction, which was paired with double-stranded DNA that can activate CRISPR-Cas12a activity by Hoogsteen pairing to form triple-stranded DNA, thereby inhibiting the binding interaction of the double-stranded DNA with CRISPR-Cas12a, which in turn inhibits the trans cleavage activity of CRISPR-Cas12a. The inhibited CRISPR-Cas12a is unable to cut the nucleic acid modified on the electrode surface, resulting in the inability of the ferrocene (Fc) modified on the other end of the nucleic acid to move away from the electrode surface, and thus failing to cause electrochemiluminescence changes in GOAu-Ru modified on the electrode surface. The extent of the electrogenic chemiluminescence change can reflect the concentration of the gene to be tested. Using this system, we achieved the detection of the SARS-CoV-2 RdRp gene with a detection limit of 32.80 aM.
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Introduction: Presence of heart failure is associated with a poor prognosis in patients with COVID-19. The aim of the present study was to examine whether first-phase ejection fraction (EF1), the ejection fraction measured in early systole up to the time of peak aortic velocity, a sensitive measure of pre-clinical heart failure, is associated with survival in patients hospitalised with COVID-19. Methods: A retrospective outcome study was performed in patients hospitalised with COVID-19 who underwent echocardiography (n=380) at the West Branch of the Union Hospital, Wuhan, China and in patients admitted to King's Health Partners in South London UK. Association of EF1 with survival was performed using Cox proportional hazards regression. EF1 was compared in patients with COVID-19 and in historical controls with similar co-morbidities (n=266) who had undergone echocardiography before the COVID-19 pandemic. Results: In patients with COVID-19, EF1 was a strong predictor of survival in each patient group (Wuhan and London). In the combined group, EF1 was a stronger predictor of survival than other clinical, laboratory and echocardiographic characteristics including age, co-morbidities and biochemical markers (figure 1). A cut-off value of 25% for EF1 gave a hazard ratio of 5.23 (95% CI: 2.85-9.60, p<0.001) unadjusted and 4.83 (95% CI: 2.35-9.95, p<0.001) when adjusted for demographics, co-morbidities, hs-cTnI and CRP (figure 2). EF1 was similar in patients with and without COVID-19 (23.2±7.3 vs 22.0±7.6%, p=0.092, adjusted for prevalence of risk factors and co-morbidities). Conclusion: Impaired first-phase ejection fraction is strongly associated with mortality in COVID-19 and probably reflects pre-existing, pre-clinical heart failure.
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OBJECTIVE: To explore the clinical efficacy of the combination of Traditional Chinese and Western Medicines for the treatment of coronavirus disease 2019 (COVID-19). METHODS: Studies were identified in six popular medical databases. RESULTS: Thirteen studies were included. The results showed that combined treatment with Traditional Chinese and Western Medicines can reduce the probability of progression from mild to severe disease [RR = 0.34, 95% confidence interval (CI) (0.18, 0.65)] (P = 0.001) and improve the clinical cure rate [RR = 0.17, 95% CI (0.05, 0.28)] (P = 0.004). The use of an integrated treatment strategy shortened the time to the remission of fever [WMD = - 1.27, 95% CI (-1.67, - 0.92)](P < 0.001) and improved the incidences of the disappearance of fever and fatigue [RR = 1.25, 95% CI (1.06, 1.47) (P = 0.007);RR = 1.49, 95% CI (1.13, 1.97) (P = 0.004)]. CONCLUSION: A combined treatment strategy is effective for COVID-19. (C) 2021 JTCM. All rights reserved.
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RATIONALE: The long-term impact of severe COVID-19 on pulmonary function, chest high-resolution CT (HRCT) pictures, and related physiological characteristics have not been understood clearly. METHODS: 25 survivors with confirmed severe COVID-19 were evaluated pulmonary function, HRCT, and health-related quality of life at seven months after discharge. The data during hospitalization were analyzed retrospectively. RESULTS: Table1 summarized the characteristics of all 25 patients at seven months after discharge. Patients with abnormal CT at seven months (n = 10) had lower albumin level (29.5[26.5-31.2] vs 32.4[30.0-36.5], p = 0.016), higher CT peak scores (24[15-24] vs 13[9-18], p = 0.002), longer cumulative days of receiving glucocorticoids (12[10-14] vs 6[0-11], p = 0.013) compared with patients with normal or basically normal CT. Then survivors were categorized as patients with abnormal DLCO and DLCO/VA, abnormal DLCO but normal DLCO/VA, and normal DLCO and DLCO/VA (n = 7, 5, and 13 respectively). Abnormal DLCO and DLCO/VA group had lower serum IL-2R level (433[326-514] vs 1218[581-1754] vs 710[562-927], p = 0.005), IL-8 level (7.20[3.15-13.25] vs 33.40[23.25-121.35] vs 17.50[6.63-47.48], p = 0.018), TNF-α level (5.80[4.80-7.80] vs 10.10[8.60-11.90] vs 9.00[7.73-12.70], p = 0.010), but higher PCT level (0.08[0.04-0.10] vs 0.03[0.03-0.10] vs 0.03[0-0.04], p = 0.036) compared with other two groups. Correlation analyses indicated that, CT scores after discharge positively correlated with age, PCT level, LDH level, cumulative days of receiving glucocorticoids, total dosage of glucocorticoids used, and CT peak scores (R = 0.409, 0.426, 0.479, 0.537, 0.528, and 0.738 respectively, p = 0.042, 0.043, 0.015, 0.007, 0.008, and < 0.001 respectively), negatively correlated with albumin level (R = -0.561, p = 0.004). DLCO% negatively correlated with total dosage of glucocorticoids used (R = -0.410, p = 0.047). DLCO/VA% positively correlated with BMI, serum IL-2R, and TNF-α level (R= 0.427, 0.560, and 0.525 respectively, p = 0.033, 0.016, and 0.025 respectively), negatively correlated with PCT level (R = -0.467, p = 0.025). Multiple linear regression analysis found that age, PCT level, and CT peak scores were associated with CT scores after discharge (β = 0.290, 0.302, and 0.428 respectively, p = 0.049, 0.030, and 0.036 respectively). BMI and PCT level were associated with DLCO/VA% (β = 0.536 and -0.463 respectively, p = 0.023 and 0.028 respectively). CONCLUSIONS: Radiological and functional impairment were still found in a considerable proportion of survivors with severe COVID-19. These statuses may be related to the severity of the disease and the level of inflammation.
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OBJECTIVE: To study the epidemiological and clinical features of children with mild coronavirus disease 2019 (COVID-19). METHODS: The children who were diagnosed with mild COVID-19 in the Wuchang Shelter Hospital in Wuhan from February 5 to March 10, 2020 were enrolled as subjects. The clinical, laboratory, and lung imaging data were collected during hospitalization and isolation. This was a retrospective single-center case series analysis. RESULTS: A total of 1 124 patients with mild COVID-19 were admitted from February 5 to March 10, 2020, including 13 children (1.16%). All the 13 children (7 boys and 6 girls) were residents of Wuhan in China, with a median age of 16 years (range: 10-18 years). Of all the 13 children, 9(69%) were from family clusters of COVID-19 and 4(31%) had unknown sources of infection. The mean time from exposure to onset was 6.8 days (range: 2-13 days) in 9 children with a definite history of exposure. There were 6 symptomatic children with the main manifestations of fever, cough, weakness, and myalgia, and the mean time from onset to hospitalization was 9.2 days. Of all the 13 children, 7(54%) were asymptomatic with positive nucleic acid test of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). There were 4 children (31%) with abnormal lung CT findings, mainly patchy shadows or ground-glass opacities in the lung field, and 6 children (46%) had no symptoms with normal lung CT findings. All children had normal routine blood test results and C-reactive protein levels. Eight children underwent SARS-CoV-2 IgM and IgG tests at least once, among whom 6 had negative SARS-CoV-2 IgM but positive IgG, and 2 underwent SARS-CoV-2 IgM and IgG tests twice and had negative results. Of all the 13 children, 11(85%) had negative results of two SARS-CoV-2 nucleic acid tests during hospitalization and were discharged, and 2(15%) had positive results of four SARS-CoV-2 nucleic acid tests and were transferred to another hospital and lost to follow-up. Among the 11 children who were followed up, 1 had positive results of two SARS-CoV-2 nucleic acid tests at the isolation point, and 10 had negative results. The mean hospital stay was 10.9 days for the 13 children. Eleven children recovered during follow-up, with good living and learning conditions. CONCLUSIONS: Children with mild COVID-19 often have an uncertain history of exposure and may not have any clinical symptoms. Etiological diagnosis is more important than clinical diagnosis. The disappearance of clinical manifestations may not parallel with the result of SARS-CoV-2 nucleic acid test. SARS-CoV-2 has a long detoxification time, and there may be recurrent cases of SARS-CoV-2 positivity. Further studies are needed to investigate the production patterns of SARS-CoV-2 IgM and IgG and their effect on the body.
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Objective: To investigate the method and application of ultrasound-guided post-mortem lung tissue sampling in cases of COVID-19. Methods: Ultrasound-guided post-mortem lung tissue sampling was performed with 14G biopsy needles in 17 confirmed COVID-19 cases in Union Hospital, Tongji Medical College, Huazhong University of Science and Technology from Feb to Mar 2020. ①Ten conventional puncture points were designed according to the anatomy of human lung lobes and the projections on the body surface. The 3rd and 6th intercostal spaces in the left midclavicular line were the puncture points for the tissues of the medial areas of the upper and lower lobes of the left lung, and the 3rd, 4th, and 6th intercostal spaces in the right midclavicular line were the puncture points of the lung tissues taken from the medial areas of the upper, middle, and lower lobes of the right lung. The 4th and 7th intercostal spaces in the left midaxillary line were the puncture points of the lung tissues from the upper and lower lateral lobes, and the 4th, 5th, and 7th intercostal spaces in the right midaxillary line were the puncture points of the lung tissues from the lateral areas of the upper, middle and lower lobes of the right lung. ②According to the sonographic findings of the lung tissues at each puncture point, it was divided into three types: air-containing lung, consolidated lung and compressed lung. And the corresponding sampling methods were designed to complete multiple points of the medial and lateral areas of the left and right lung lobes. ③The time required for each lung sampling was recorded, and the sizes of the specimens were measured. The success rates of all puncture points were compared and the success rates of various type lung tissues were compared. Results: ①In 17 COVID-19 death cases, 174 puncture points were selected for bilateral lung tissues, and 288 lung tissue specimens were obtained by puncture. ②There were differences in the success rates of the puncture points, and the success rate of the 6th intercostal puncture points on the left and right midclavicular lines were lower than those of the other puncture points(P<0.05). ③There were differences in the success rate of corpse lung sampling with different types of ultrasonographic performance. The success rates of gas-containing lung sampling was 74.4%, which was lower than that of consolidation lung (86.8%)and compressed lung(84.1%)(P<0.05). ④The length of the compressed lung specimen was 11.4(10.6, 12.3)mm, which was lower than that of gas-containing lung and consolidation lung[14.6(12.5, 15.2)mm, 13.5(12.5, 15.0)mm] (P<0.05). Conclusions: This study introduces an ultrasound-guided minimally invasive puncture method for cadaver lung tissue sampling, and itmay be a reliable method for collecting lung tissues in COVID-19 cases. © 2020 Chinese Medical Association