Breeding Hope during the Crisis: A Study on Unemployed Laborers' Willingness to Receive Educational Compensation under the Chinese "Zero-COVID” Policy

Under the Chinese "Zero-COVID” policy, many laborers were forced out of work. Participating in educational compensation can effectively help unemployed laborers achieve re-employment. This paper selected Jining, Shandong Province, as the research area, analyzed the data using a questionnaire survey and key interviews, and observed factors that affect and change willingness to receive educational compensation (WTEC) and the willingness to accept the training duration (WTTD) of unemployed laborers. The study found that 77.78% of unemployed laborers are willing to receive educational compensation, and the WTTD is 12.05 days. Among them, eight factors affect WTEC, such as the years of education, the duration of unemployment, whether there are dependents in the family, and the family's size. Nine factors such as gender, age, education, unemployed duration, dependents, and other supportable incomes affect WTTD. Based on this, by taking measures from the government and laborers, WTEC and WTTD can be improved, and then the rate of re-employment can be enhanced, and finally, the employment problem can be ameliorated.

Home quarantine during COVID-19 blunted childhood trauma-related psychiatric symptoms in Chinese college students.

Background: Childhood trauma confers risks to mental health. However, little is known about whether home quarantine (HQ) during the coronavirus disease 2019 (COVID-19) pandemic exaggerated or mitigated the effect of childhood trauma on mental health. Objective: To examine the modulating effects of prior childhood traumas on the longitudinal changes of psychiatric symptoms in college students before and after HQ during the pandemic. Methods: This was a two-wave longitudinal study on the mental health of 2,887 college students before and after HQ during the COVID-19 pandemic. The relationships between the changes in the Patient Health Questionnaire-9 (PHQ-9), Symptom Checklist-90 (SCL-90), 16-item Prodromal Questionnaire (PQ-16), Childhood Trauma Questionnaire (CTQ), and Social Support Rating Scale (SSRS) scores were analyzed. Results: The students with childhood trauma showed a significantly greater decrement in psychiatric symptoms after HQ (F = 17.21, 14.11, 18.87, and 17.42 for PHQ-9, PQ-16 objective and distress, and SCL-90, respectively). The correlation coefficients between the CTQ and these symptoms scales were significant at baseline (r = 0.42, 0.34, 0.37, and 0.39), and decreased after HQ (r = 0.17, 0.20, 0.18, and 0.19). The decrement of depressive, psychotic, and overall symptoms was positively correlated with the scores of the CTQ (r = 0.08-0.27) but negatively correlated with SSRS (r = -0.08--0.14). Multilinear regression analysis confirmed the results of the CTQ and SSRS regarding the modulation of the dynamic changes in psychiatric symptoms. A constructed structural equation model indicated that the total effects of childhood trauma on decreased psychiatric symptoms were partly mediated by lower baseline social support. Conclusion: Home quarantine during the COVID-19 pandemic could blunt the adverse effects of childhood trauma on mental health, especially for prodromal psychotic symptoms in college students. Changes in relative deprivation and social support may be mediating factors.

Food Sources May Affect the Symptom Rates of COVID-19, an Epidemiological Analysis Based on the Public Data in Gansu Province, China, During the Summer Epidemic Cycle in 2022.

According to the public data collected from the Health Commission of Gansu Province, China, regarding the COVID-19 pandemic during the summer epidemic cycle in 2022, the epidemiological analysis showed that the pandemic spread stability and the symptom rate (the number of confirmed cases divided by the sum of the number of asymptomatic cases and the number of confirmed cases) of COVID-19 were different among 3 main epidemic regions, Lanzhou, Linxia, and Gannan; both the symptom rate and the daily instantaneous symptom rate (daily number of confirmed cases divided by the sum of daily number of asymptomatic cases and daily number of confirmed cases) in Lanzhou were substantially higher than those in Linxia and Gannan. The difference in the food sources due to the high difference of the population ethnic composition in the 3 regions was probably the main driver for the difference of the symptom rates among the 3 regions. This work provides potential values for prevention and control of COVID-19 in different regions.

Impact of social comparison on perceived online academic futility: A perspective from parents.

In response to the wide-ranging concern of online academic futility, the current study aimed to explore the independent variables and mediating variable from a novel perspective of parents during COVID-19. Based on the social comparison theory and the control-value theory of achievement emotions, social comparison and tutoring anxiety were incorporated into an integrated model as predictors and mediator, respectively. A total of 300 parents completed an online survey. The results of the structural equation modeling indicated that upward social comparison and downward social comparison were both positively related to tutoring anxiety, which in turn positively predicted perceived online academic futility. Notably, tutoring anxiety played a significant mediating role in the association between different social comparison and perceived online academic futility. These results highlight the consistent predictive effect of upward social comparison and downward social comparison on perceived online academic futility, shedding light on the roles of tutoring anxiety in explaining the relationship from parental perspectives.

Developing supply chain resilience through integration: An empirical study on an e‐commerce platform

The outbreak of the COVID‐19 pandemic has disrupted supply chains and increased the uncertainties faced by firms. While firms are struggling to survive and recover from the pandemic, Chinese e‐commerce platforms have demonstrated resilient supply chains. We develop a framework that investigates the impacts of integration between an e‐commerce platform and suppliers on supply chain resilience and the moderating effect of the suppliers' product flexibility. An analysis of data from a Chinese e‐commerce platform using operational indicators finds that integration between the e‐commerce platform and suppliers in terms of information sharing, joint planning and logistics cooperation has positive impacts on supply chain resilience, while procurement automation has the opposite effect. Furthermore, product flexibility positively moderates the impacts of information sharing, joint planning and logistics cooperation. The results enhance current understandings of the factors that contribute to the development of supply chain resilience and reveal that the relationship between integration and resilience should be examined within a contingency framework. The findings also provide guidelines for managers taking measures to mitigate the negative influences of supply chain disruptions.

Mapping the trophic state index of eastern lakes in China using an empirical model and Sentinel-2 imagery data

Lake eutrophication has become a critical environmental issue due to the global effects of anthropogenic activities and climate change, and has been comprehensively studied for many years. A series of models and indicators have been proposed to assess the trophic state of lakes. The trophic state index (TSI) is a synthetic index that integrates chlorophyll-a, water clarity, and total phosphorus and is widely used to evaluate the trophic state of aquatic environments. In this study, we collected in situ lake samples (N = 431) from typical lakes to match Sentinel-2 MultiSpectral Instrument (MSI) imagery data using the Case 2 Regional Coast Color processor. Then we developed a new empirical model, TSI = -34.04 x (band 4/band 5) - 1.114 x (band 1/band 4) + 97.376. This model is valid for all of China, with good performance and few errors (RMSE = 7.36;MAE = 6.25) for the validation dataset. Recognizing that over 94% of the Chinese population located along eastern watersheds and large lakes have competing water uses, and given the TSI model on the seasonal scales, we further estimated the mean TSI and trophic state in eastern Chinese lakes (> 100 km2) from 2019 to 2020. The results revealed that more lakes were eutrophic in autumn (94.28%) than in spring (> 77.14%), indicating a serious eutrophication of eastern lakes. Although the eastern lakes have been studied in more detail, this study found that eutrophication still has markedly negative impacts on lake ecosystems. In addition, no significant improvement was observed in spring, most likely due to the months of curfew/lockdown from January 2020 onwards due to COVID-19. This may be due to the enrichment of nutrients deposited in sediment or watershed soil, which can be characterized as "autochthonous sources" of lake eutrophication, over decades with high rates of economic development. This study demonstrates the applicability of Sentinel-2 MSI data to monitor lake eutrophication as well as the feasibility of blue/red and red/red edge combinations. The framework and TSI model used bands available on MSI sensors to develop a novel approach for generating historical eutrophication data for large-scale evaluation of and decision-making related aquatic environmental changes, even in poorly studied areas.

Does COVID-19 reduce international cooperation in supply chain research between the US and China?

PurposeThe purpose of this research is to systematically analyze the existing literature of the supply chain to explore the impact of COVID-19 on the international cooperation in supply chain research between the US and China.Design/methodology/approachSupply chain publications obtained from the Scopus database were analyzed using statistical technique and visual analysis. First, created three datasets of supply chain publications for three time periods: 2010–2019, 2015–2019 and 2020–2021. Then, compared the changes in international cooperation in supply chain research between the US and China before and during the epidemic, as well as the international cooperation patterns for the two countries.FindingsThe study found that during the pandemic, the average monthly number of collaborative publications between China and the US on supply chain research was higher than the five and the ten years before the epidemic. In other words, the epidemic has not led to a decline in international cooperation between the US and China. On the contrary, the epidemic has stimulated international cooperation on supply chain research in the two countries. Secondly, research on the international cooperation patterns of supply chain research shows that China and the US have always been each other's largest partners, and the two countries have generally maintained or increased international cooperation with their top research producing countries during the epidemic. In addition, in supply chain research during the epidemic, the proportion of US–China cooperation in China's international cooperation has declined, while that of the US has increased.Research limitations/implicationsThe time span of the datasets used to analyze the research status before and during COVID-19 is different. Due to the nature of data collection, available time of the dataset during COVID-19 is much shorter. Publications during the COVID-19 continue to grow, and the trends shown by the research results may change somewhat. Furthermore, the search query may not be comprehensive enough to capture all publications related to the supply chain.Practical implicationsThe research results help determine the impact of the COVID-19 outbreak on international cooperation in US–China supply chain research, and it is of great significance to researchers and policymakers in the field of logistics and supply chain operations.Originality/valueThis study gives a feasible analysis strategy for international cooperative research, which adds great value to this field.

Multifunctional composite coatings with hydrophobic, UV-resistant, anti-oxidative, and photothermal performance for healthcare.

Personal protective textiles have attracted extensive interest since Corona Virus Disease 2019 has broken out. Moreover, developing eco-friendly, multifunctional waterproof, and breathable surface is of great importance but still faces enormous challenges. Notably, good hydrophobicity and breathability are necessary for protective textiles, especially protective clothing and face masks for healthcare. Herein, the multifunctional composite coatings with good UV-resistant, anti-oxidative, hydrophobic, breathable, and photothermal performance has been rapidly created to meet protective requirements. First, the gallic acid and chitosan polymer was coated onto the cotton fabric surface. Subsequently, the modified silica sol was anchored on the coated cotton fabric surface. The successful fabrication of composite coatings was verified by RGB values obtained from the smartphone and K/S value. The present work is an advance for realizing textile hydrophobicity by utilizing fluorine-free materials, compared with the surface hydrophobicity fabricated with conventional fluorinated materials. The surface free energy has been reduced from 84.2 to27.6 mJ/m2 so that the modified cotton fabric could repel the ethylene glycol, hydrochloric acid, and sodium hydroxide solutions, respectively. Besides, the composite coatings possesses lower adhesion to deionized water. After 70 cycles of the sandpaper abrasion, the fluorine-free hydrophobic coatings still exhibits good hydrophobicity with WCA of 124.6 ± 0.9°, with overcoming the intrinsic drawback of the poor abrasion resistance of hydrophobic surfaces. Briefly, the present work may provide a universal strategy for rapidly creating advanced protective coatings to meet personal healthcare, and a novel method for detecting RGB values of composite coatings by smartphone.

Assessing vaccine literacy and exploring its association with vaccine hesitancy: A validation of the vaccine literacy scale in China.

BACKGROUND: Assessment of vaccine literacy is essential for understanding people's ability to access various vaccine information to meet health demands. Few studies have examined the role of vaccine literacy in vaccine hesitancy, which is a psychological state. This study aimed to validate the applicability of the HLVa-IT (Vaccine Health Literacy of Adults in Italian) scale in Chinese settings and to explore the association between vaccine literacy and vaccine hesitancy. METHODS: From May to June 2022, we conducted an online cross-sectional survey in mainland China. Potential factor domains were obtained by the exploratory factor analysis. Cronbach's alpha coefficient, composite reliability values, and square root values of average variances extracted were calculated to determine the internal consistency and discriminant validity. The association between vaccine literacy, vaccine acceptance, with vaccine hesitancy was assessed using logistic regression analysis. RESULTS: Totally, 12,586 participants completed the survey. Two potential dimensions, the functional and the interactive/critical, were identified. Cronbach's alpha coefficient and composite reliability values were >0.90. The square root values of average variances extracted exceeded the related correlations. The functional dimension (adjusted odds ratio (aOR): 0579; 95 % Confidence Interval (CI); 0.529, 0.635), interactive (aOR: 0.654; 95%CI: 0.531, 0.806)/critical (aOR: 0.709; 95%CI: 0.575, 0.873) dimension were significantly and negatively associated with vaccine hesitancy. Similar results were also found in different vaccines acceptance subgroups. LIMITATIONS: This report is limited by the convenience sampling method. CONCLUSIONS: The modified HLVa-IT is suitable for use in Chinese settings. Vaccine literacy was negatively associated with vaccine hesitancy.

Face Mask Identification Using Spatial and Frequency Features in Depth Image from Time-of-Flight Camera.

Face masks can effectively prevent the spread of viruses. It is necessary to determine the wearing condition of masks in various locations, such as traffic stations, hospitals, and other places with a risk of infection. Therefore, achieving fast and accurate identification in different application scenarios is an urgent problem to be solved. Contactless mask recognition can avoid the waste of human resources and the risk of exposure. We propose a novel method for face mask recognition, which is demonstrated using the spatial and frequency features from the 3D information. A ToF camera with a simple system and robust data are used to capture the depth images. The facial contour of the depth image is extracted accurately by the designed method, which can reduce the dimension of the depth data to improve the recognition speed. Additionally, the classification process is further divided into two parts. The wearing condition of the mask is first identified by features extracted from the facial contour. The types of masks are then classified by new features extracted from the spatial and frequency curves. With appropriate thresholds and a voting method, the total recall accuracy of the proposed algorithm can achieve 96.21%. Especially, the recall accuracy for images without mask can reach 99.21%.

Association between trans fatty acids and COVID-19: A multivariate Mendelian randomization study.

Traditional observational studies have suggested a potential association between trans fatty acids (TFAs), which are considered to be health-damaging fatty acids, and coronavirus disease 2019 (COVID-19). However, whether there is a causal relationship between them is currently unclear. We aimed to investigate the causal link between genetically determined TFAs and COVID-19. We performed univariate and multivariate Mendelian randomization (MR) studies using summary statistics from the European Pedigree TFAs (n = 8013), COVID-19 susceptibility (n = 159 840), COVID-19 hospitalization (n = 44 986), and COVID-19 severity (n = 18 152) genome-wide association studies (GWAS). The inverse variance weighted (IVW) method was used as the primary MR analysis, and several other methods were used as supplements. In univariate MR analysis, higher levels of circulating trans, cis-18:2 TFAs were positively associated with a higher COVID-19 hospitalization rate (p < 0.0033; odds ratio [OR] = 1.637; 95% confidence interval [CI]: 1.116-2.401) and COVID-19 severity (p < 0.0033; OR = 2.575; 95% CI: 1.412-4.698). Furthermore, in multivariate MR analysis, trans, cis-18:2 had an independent and significant causal association with a higher COVID-19 hospitalization rate (p = 0.00044; OR = 1.862; 95% CI = 1.316-2.636) and COVID-19 severity (p = 0.0016; OR = 2.268; 95% CI = 1.361-3.779) after the five TFAs were adjusted for each other. Together, our findings provide evidence that trans, cis-18:2 TFAs have an independent and robust causal effect on COVID-19 hospitalization and severity.

How does digitalisation influence supply chain performance? Evidence from a supply chain risk management perspective

This study explores the contribution of supply chain digitalisation (SCD) to supply chain performance (SCP) via the mediating roles of SC responsiveness, resilience, and restoration (SC 3Rs) and examines the moderating effects of the COVID-19 pandemic from a risk management perspective. We surveyed 215 Chinese companies from January to April 2021 and examined the hypothesised relationships in a moderated mediation model. We find that SCD positively affects SC 3Rs, which in turn play positive mediating roles in the relationship between SCD and SCP, and that the mediating effects are stronger when pandemic impact is higher. The results of post-hoc analyses indicate that the mediating role of SC resilience is stronger than those of SC responsiveness and SC restoration. These findings enrich our understanding of how the roles of SCD and SC 3Rs vary in a turbulent context, contributing to both academic research and practice on digitalisation for a sustainable SC.

Understanding Drivers of Vaccine Hesitancy During the COVID-19 Pandemic Among Older Adults in Jiangsu Province, China: Cross-sectional Survey.

BACKGROUND: Older adults are particularly at risk from infectious diseases, including serve complications, hospitalization, and death. OBJECTIVE: This study aimed to explore the drivers of vaccine hesitancy among older adults based on the "3Cs" (confidence, complacency, and convenience) framework, where socioeconomic status and vaccination history played the role of moderators. METHODS: A cross-sectional questionnaire survey was conducted in Jiangsu Province, China, between June 1 and July 20, 2021. Older adults (aged ≥60 years) were recruited using a stratified sampling method. Vaccine hesitancy was influenced by the 3Cs in the model. Socioeconomic status and vaccination history processed through the item parceling method were used to moderate associations between the 3Cs and hesitancy. Hierarchical regression analyses and structural equation modeling were used to test the validity of the new framework. We performed 5000 trials of bootstrapping to calculate the 95% CI of the pathway's coefficients. RESULTS: A total of 1341 older adults participated. The mean age was 71.3 (SD 5.4) years, and 44.7% (599/1341) of participants were men. Confidence (b=0.967; 95% CI 0.759-1.201; P=.002), convenience (b=0.458; 95% CI 0.333-0.590; P=.002), and less complacency (b=0.301; 95% CI 0.187-0.408; P=.002) were positively associated with less vaccine hesitancy. Socioeconomic status weakened the positive effect of low complacency (b=-0.065; P=.03) on low vaccine hesitancy. COVID-19 vaccination history negatively moderated the positive association between confidence (b=-0.071; P=.02) and lower vaccine hesitancy. CONCLUSIONS: Our study identified that confidence was the more influential dimension in reducing vaccine hesitancy among older adults. COVID-19 vaccination history, as well as confidence, had a positive association with less vaccine hesitancy and could weaken the role of confidence in vaccine hesitancy. Socioeconomic status had a substitution relationship with less complacency, which suggested a competitive positive association between them on less vaccine hesitancy.

COVID-19 infection rate but not severity is associated with availability of greenness in the United States.

Human exposure to greenness is associated with COVID-19 prevalence and severity, but most relevant research has focused on the relationships between greenness and COVID-19 infection rates. In contrast, relatively little is known about the associations between greenness and COVID-19 hospitalizations and deaths, which are important for risk assessment, resource allocation, and intervention strategies. Moreover, it is unclear whether greenness could help reduce health inequities by offering more benefits to disadvantaged populations. Here, we estimated the associations between availability of greenness (expressed as population-density-weighted normalized difference vegetation index) and COVID-19 outcomes across the urban-rural continuum gradient in the United States using generalized additive models with a negative binomial distribution. We aggregated individual COVID-19 records at the county level, which includes 3,040 counties for COVID-19 case infection rates, 1,397 counties for case hospitalization rates, and 1,305 counties for case fatality rates. Our area-level ecological study suggests that although availability of greenness shows null relationships with COVID-19 case hospitalization and fatality rates, COVID-19 infection rate is statistically significant and negatively associated with more greenness availability. When performing stratified analyses by different sociodemographic groups, availability of greenness shows stronger negative associations for men than for women, and for adults than for the elderly. This indicates that greenness might have greater health benefits for the former than the latter, and thus has limited effects for ameliorating COVID-19 related inequity. The revealed greenness-COVID-19 links across different space, time and sociodemographic groups provide working hypotheses for the targeted design of nature-based interventions and greening policies to benefit human well-being and reduce health inequity. This has important implications for the post-pandemic recovery and future public health crises.

Plastic pollution induced by the COVID-19: Environmental challenges and outlook.

The COVID-19 pandemic has also caused an environmental challenge, especially plastic pollution. This study is aimed to provide a systematic review of the current status and outlook of research on plastic pollution caused by the COVID-19 pandemic using a bibliometrics approach. The results indicate developed countries were the first to pay attention to the impact of plastics on the ocean and ecological environment during COVID-19 and conducted related research, and then developing countries followed up and started research. Research in developed countries is absolutely dominant in plastic pollution induced by the COVID-19, although the plastic pollution faced by developing countries is also very serious. The author's co-occurrence analysis shows the Matthew effect. Keyword clustering shows that plastics have a harsh chain-like impact on the ecological environment from land to ocean to atmosphere. The non-degradable components of plastic bring a serious impact the ocean ecosystems, and then pose a serious threat to the entire ecosystem environment.

Chinese expert consensus on intestinal microecology and management of digestive tract complications related to tumor treatment (version 2022).

The human gut microbiota represents a complex ecosystem that is composed of bacteria, fungi, viruses, and archaea. It affects many physiological functions including metabolism, inflammation, and the immune response. The gut microbiota also plays a role in preventing infection. Chemotherapy disrupts an organism's microbiome, increasing the risk of microbial invasive infection; therefore, restoring the gut microbiota composition is one potential strategy to reduce this risk. The gut microbiome can develop colonization resistance, in which pathogenic bacteria and other competing microorganisms are destroyed through attacks on bacterial cell walls by bacteriocins, antimicrobial peptides, and other proteins produced by symbiotic bacteria. There is also a direct way. For example, Escherichia coli colonized in the human body competes with pathogenic Escherichia coli 0157 for proline, which shows that symbiotic bacteria compete with pathogens for resources and niches, thus improving the host's ability to resist pathogenic bacteria. Increased attention has been given to the impact of microecological changes in the digestive tract on tumor treatment. After 2019, the global pandemic of novel coronavirus disease 2019 (COVID-19), the development of novel tumor-targeting drugs, immune checkpoint inhibitors, and the increased prevalence of antimicrobial resistance have posed serious challenges and threats to public health. Currently, it is becoming increasingly important to manage the adverse effects and complications after chemotherapy. Gastrointestinal reactions are a common clinical presentation in patients with solid and hematologic tumors after chemotherapy, which increases the treatment risks of patients and affects treatment efficacy and prognosis. Gastrointestinal symptoms after chemotherapy range from nausea, vomiting, and anorexia to severe oral and intestinal mucositis, abdominal pain, diarrhea, and constipation, which are often closely associated with the dose and toxicity of chemotherapeutic drugs. It is particularly important to profile the gastrointestinal microecological flora and monitor the impact of antibiotics in older patients, low immune function, neutropenia, and bone marrow suppression, especially in complex clinical situations involving special pathogenic microbial infections (such as clostridioides difficile, multidrug-resistant Escherichia coli, carbapenem-resistant bacteria, and norovirus).

Bridging the research-practice gap in supply chain risks induced by the COVID-19

PurposeThis study aims to explore the gap between research and practice on supply chain risks due to COVID-19 by exploring the changes in global emphasis on supply chain risk research.Design/methodology/approachThis work designed a research framework to compare the research of supply chain risks before and during the COVID-19 pandemic based on machining learning and text clustering and using the relevant publications of the web of science database.FindingsThe results show that scholars' attention to supply chain crisis has increased in the wake of the COVID-19 outbreak, but there are differences among countries. The United Kingdom, India, Australia, the USA and Italy have greatly increased their emphasis on risk research, while the supply chain risk research growth rate in other countries, including China, has been lower than the global level. Compared with the pre-pandemic period, the research of business finance, telecommunications, agricultural economics policy, business and public environmental occupational health increased significantly during the pandemic. The hotspots of supply chain risk research have changed significantly during the pandemic, focusing on routing problem, organizational performance, food supply chain, dual-channel supply chain, resilient supplier selection, medical service and machine learning.Research limitations/implicationsThis study has limitations in using a single database.Social implicationsThis work compared the changes in global and various countries' supply chain risk research before and during the pandemic. On the one hand, it helps to judge the degree of response of scholars to the global supply chain risk brought about by COVID-19. On the other hand, it is beneficial for supply chain practitioners and policymakers to gain an in-depth understanding of the relationship between the COVID-19 pandemic and supply chain risk, which might provide insights into not only addressing the supply chain risk but also the recovery of the supply chain.Originality/valueThe initial exploration of the changing extent of supply chain risk research in the context of COVID-19 provided in this paper is a unique and earlier attempt that extends the findings of the existing literature. Secondly, this research provides a feasible analysis strategy for supply chain risk research, which provides a direction and paradigm for exploring more effective supply chain research to meet the challenges of COVID-19.

Distribution characteristics of SARS-CoV-2 IgM/IgG in false-positive results detected by chemiluminescent immunoassay.

There have been several false-positive results in the antibody detection of COVID-19. This study aimed to analyze the distribution characteristics of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immunoglobulin M (IgM) and immunoglobulin G (IgG) in false-positive results using chemiluminescent immunoassay. The characteristics of false-positive results in SARS-CoV-2 IgM and IgG tests were analyzed. The false-positive proportion of single SARS-CoV-2 IgM-positive results was 95.88%, which was higher than those of single SARS-CoV-2 IgG-positive results (71.05%; p < 0.001) and SARS-CoV-2 IgM- and IgG-positive results (39.39%; p < 0.001). The S/CO ratios of SARS-CoV-2 IgM and IgG in false-positive results ranged from 1.0 to 50.0. The false-positive probability of SARS-CoV-2 IgM in the ratios of specimen signals to the cutoff value (S/CO) range (1.0-3.0) was 95.06% (77/81), and the probability of false-positive results of SARS-CoV-2 IgG in the S/CO range (1.0-2.0) was 85.71% (24/28). Dynamic monitoring showed that the S/CO values of IgM in false-positive results decreased or remained unchanged, whereas the S/CO values of IgG in false-positive results decreased. The possibility of false-positive single SARS-CoV-2 IgM-positive and single SARS-CoV-2 IgG-positive results was high. As the value of S/CO ratios decreased, the probability of false-positives consequently increased, especially among the single SARS-CoV-2 IgM-positive results.

The analytical strategy of GICA and CLIA combination in SARS-CoV-2 antibodies detection

To evaluate the effect of colloidal gold immunochromatographic assay (GCIA) combined with chemiluminescent immunoassay (CLIA) in reducing the false positive of antibodies against severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2). Thirty-three serum samples from 19 patients with SARS-CoV-2 infection at different times, and 55 serum samples from 55 patients not infected with SARS-CoV-2. but infected instead with other pathogens or suffering from autoimmune diseases were collected from the Affiliated Hospital of North Sichuan Medical College and Nanchong Central Hospital from 22 January to 5 March 2020. Serum IgM and IgG against SARS-CoV-2 were detected by GICA and CLIA respectively, and the results were analyzed. The sensitivity of GCIA for detection of IgM and IgG against SARS - CoV - 2 was 100.0% and 94.74%. respectively, values that were similar with those for CLIA (92.86% and 100.0%) (P = 1.000). The specificity of GCIA for IgM and IgG against SARS-CoV-2 was 70.91% and 74.55% respectively, which was significantly lower than that of CLIA (98.18% and 89.09%) (P < 0.01). The results of IgM and IgG against SARS-CoV-2 detected by the two methods were consistent (P=0.000) . and their Kappa was 0.434 and 0.406. respectively. Analyses of ROC curves showed that the AUC of IgM and IgG against SARS-CoV-2 detected by GCIA was 0.855 and 0.846. respectively, which was significantly lower than that of CLIA (0.955 and 0.945, respectively) (PC0.05). The sensitivity of combined detection of IgM and IgG against SARS -CoV-2 was 92.86% and 94.74%. and the specificity was 100.0% and 100.0%, respectively. Analyses of ROC curves showed that the AUC of combined detection of IgM and IgG against SARS-CoV-2 was 0.964 and 0.974. respectively, which was higher titan that of each method alone. GCIA combined with CLIA can improve the specificity of detection of IgM and IgG against SARS-CoV-2, which may merit clinical application.