ABSTRACT
Objective: The gold immunochromatographic assay for detection of SARS-CoV-2 antigen was evaluated by international multi-center clinical trial. Methods: A total of 1 855 clinical parallel samples with valid test results (for nucleic acid and antigen tests, respectively) were collected from nine countries, including Germany, the United Kingdom, Ukraine, France, India, Thailand, Malaysia, the United States of America and Brazil, with sampling period from January 3, 2021 to September 22, 2021. These samples were detected by SARS-CoV-2 antigen test kit (colloidal gold immunochromatography assay) and nucleic acid detection kit (real-time fluorescent quantitative reverse transcription polymerase chain reaction). Positive coincidence rates [(number of antigen-positive cases/nucleic acid-positive cases)×100%], negative coincidence rates [(number of antigen-negative cases/nucleic acid-negative cases)×100%], total coincidence rates [(number of cases with consistent results for both antigen and nucleic acid detection/number of total cases) ×100%], as well as Kappa values were calculated. The differences of the above indictors among different countries were evaluated by the coefficient of variation. The detection rates of the antigen test for samples with different cycle threshold values (Ct values) for the nucleic acid detection, different characteristics and different mutant strains were analyzed. Results: For all samples, the positive, negative, and total coincidence rate between the antigen test and nucleic acid assay was 90.8% (569/627), 99.7% (1 224/1 228) and 96.7% (1 793/1 855), respectively, and the consistency coefficient Kappa value was 0.924. Among these countries, the coefficient of variation for positive coincidence rates (except for Malaysia with a lot of samples with Ct value>30), negative coincidence rates (except for France without negative samples) and total coincidence rates (except for France) was 6%,<1%, and 6%, respectively. When Ct values were less than 25, the detection rates of antigen test were 83.3%-100% for each countries (the coefficient of variation was 6%); The total detection rate and the coefficient of variation was 93.4% (428/458) and 5%, respectively, for asymptomatic infected persons and cases within 7 days post onset of symptoms; the total detection rate for various SARS-CoV-2 mutant strains was 97.5% (119/122); and it showed negative results for samples from cases infected with other viruses, including influenza A virus subtype H1N1, influenza B virus, respiratory syncytial virus subgroups A and B, coxsackievirus 16, human metapneumovirus, parainfluenza virus types 1 and 4, Epstein-Barr virus and adenovirus. Conclusion: The SARS-CoV-2 antigen test kit showed excellent authenticity, and there were few differences for its indictors among nine countries, therefore it can meet the needs of large-scale early screening of SARS-CoV-2 infection.
ABSTRACT
In the post-MOOC era, combining the respective advantages of traditional teaching models and MOOCs, SPOC is more suitable to apply the diverse teaching resources to small-scale and specific learners as an indispensable bridge between the traditional classrooms and MOOC platforms. With the outbreak of the COVID-19 pandemic, the urgent demand of long-distance online teaching had impelled Chinese teachers and students to make full use of the online teaching and learning techniques, thereof the SPOC blended teaching and learning mode had been widely adopted by national colleges and universities in China. Two surveys on the online teaching and learning platforms were carried out during the COVID-19 pandemic: a large-scale investigation on the undergraduates online teaching and learning in Beijing showed, the online learning students preferred SPOC for accessing adequate online learning resources;our online survey on SPOC online teaching and learning platforms at three higher vocational colleges in Anhui Province showed, the teachers and students held the positive attitude towards teaching mode, evaluation method, evaluation quantity, task exploration, and resource display, but learning resources, interactive platform, activity arrangement, classroom task, and communication quality to be improved. On the basis of comparison, investigation and interview on MOOC and SPOC, the study puts forward the designing method of SPOC blended teaching and learning mode, which consists of five teaching procedures of analysis, design, development, implementation and evaluation before, during and after the online teaching and learning.