Perceptions towards online learning among medical students during the COVID-19 pandemic.

Social distancing has been essential during the COVID-19 pandemic to slow the spread of the disease. Online learning ensures students can participate in learning activities while also maintaining a physical distance from other students. Although online learning was used to prevent the spread of COVID-19, the development of online learning has also been promoted. Here, we sought to explore the perceptions and responses of students to online learning during the pandemic using a cross-sectional study. Electronic questionnaire was used for data collection. Statistical analyses were performed for 1614 valid questionnaires and P < 0.05 was considered statistically significant. Overall, COVID-19 had more effect on female students, such as fear of COVID-19 (2.4 times higher than the number of male students) and length of time spent learning (H = 42.449, P < 0.05). However, the higher the students' grades were, the less the impact of COVID-19. For the style of lessons, all students would prefer shorter lessons (P < 0.05). Female and fifth-grade students were more prefer combined online and face-to-face learning, and male and freshmen students were more likely to prefer face-to-face learning after the pandemic. More than 50% of students thought the main advantage of online learning was convenience, with low efficiency being a disadvantage. The main factors negatively influencing online learning were eyestrain, poor network connections, and poor learning environments at home. In conclusion, synchronous online and face-to-face learning may become more common in future curricula, however the efficiency of online learning and the female students more attentions.

Low prevalence of antibodies against SARS-CoV-2 among voluntary blood donors in Guangzhou, China.

Since the first case of COVID-19 reported in late December of 2019 in Wuhan, China, the SARS-CoV-2 virus has caused approximately 20 million infections and 732 thousand deaths around the world by 11 August 2020. Although the pathogen generally infects the respiratory system, whether it is present in the bloodstream and whether it poses a threat to the blood supply during the period of the outbreak is of serious public concern. In this study, we used enzyme-linked immunosorbent assay (ELISA) to screen total antibodies against SARS-CoV-2 in 2199 blood donors, who had donated blood at the Guangzhou Blood Center during the epidemic. The Ig-reactive samples were further characterized for IgA, IgG, and IgM subtypes by ELISA and viral nucleic acid by real-time polymerase chain reaction. Among the 2199 plasma samples, seven were reactive under total antibodies' screening. Further testing revealed that none of them had detectable viral nucleic acid or IgM antibody, but two samples contained IgA and IgG. The IgG antibody titers of both positive samples were 1:16 and 1:4, respectively. Our results indicated a low prevalence of past SARS-CoV-2 infection in our blood donors, as none of the tests were positive for viral nucleic acid and only 2 out of 2199 (0.09%) of samples were positive for IgG and IgA. There would be a limited necessity for the implementation of such testing in blood screening in a COVID-19 low-risk area.

Public health risks of regional assessment of the coronavirus diseases 2019 in Wenzhou, Zhejiang

Objective To establish an index system for comprehensive evaluation of public health risks of the coronavirus diseases 2019(COVID-19),and to evaluate the COVID-19 in different counties(districts) of Wenzhou, so as to provide scientific evidence for the implementation of targeted prevention and control measures. Methods Rank-sum ratio(RSR) was used to evaluate 12 quality indicators of 5 categories by brain storming method with data including the incidence of COVID-19 and public health risks of COVID-19 epidemic in Wenzhou during January and February, 2020.The regional public health risks of COVID-19 were ranked according to rank-sum ratio size. Results The top three counties(districts) with most reported cases were Yueqing,Rui′an and Lucheng,accounting for 61.90%(312/504) of the total number in Wenzhou.The ratio of import cases to indigenous cases was 1∶1.39.The top three counties(districts) reported most clustering epidemics were Yueqing,Rui′an and Lucheng,accounting for 62.03%(49/79) of the total number in Wenzhou.About 70.63%(356/504)of the cases were found before the medical visit.The time from onset to first medical visit was 2.39 d, and the time from medical visit to diagnosis was 4.49 d.The average number of close contacts for confirmed cases was 29,and the top three counties(districts)with most reported average number of close contacts were Jingkai(135 cases),Dongtou(59 cases)and Cangnan(50 cases).Among all13 counties(districts),Longgang,Wencheng and Jingkai were at lower level,Yueqing and Lucheng were at higher level,and the other counties(districts)were at the middle level of public health risks of COVID-19. Conclusions RSR method is flexible and simple.It has no specific requirements on samples,and can eliminate the effects of comprehensive assessment indexes of different dimension.It has high value in evaluating public health risks of the COVID-19.The evaluating of public health risks of COVID-19 should be strengthened.Targeted prevention and control measures should be taken to positively prevent the outbreak of COVID-19.

Structural insight reveals SARS-CoV-2 ORF7a as an immunomodulating factor for human CD14+ monocytes.

Dysregulated immune cell responses have been linked to the severity of coronavirus disease 2019 (COVID-19), but the specific viral factors of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were currently unknown. Herein, we reveal that the Immunoglobulin-like fold ectodomain of the viral protein SARS-CoV-2 ORF7a interacts with high efficiency to CD14+ monocytes in human peripheral blood, compared to pathogenic protein SARS-CoV ORF7a. The crystal structure of SARS-CoV-2 ORF7a at 2.2 Å resolution reveals three remarkable changes on the amphipathic side of the four-stranded ß-sheet, implying a potential functional interface of the viral protein. Importantly, SARS-CoV-2 ORF7a coincubation with CD14+ monocytes ex vivo triggered a decrease in HLA-DR/DP/DQ expression levels and upregulated significant production of proinflammatory cytokines, including IL-6, IL-1ß, IL-8, and TNF-α. Our work demonstrates that SARS-CoV-2 ORF7a is an immunomodulating factor for immune cell binding and triggers dramatic inflammatory responses, providing promising therapeutic drug targets for pandemic COVID-19.