Factors affecting the transmission of SARS-CoV-2 in school settings.

BACKGROUND: Several studies have reported SARS-CoV-2 outbreaks in schools, with a wide range of secondary attack rate (SAR; range: 0-100%). We aimed to examine key risk factors to better understand SARS-CoV-2 transmission in schools. METHODS: We collected records of 35 SARS-CoV-2 school outbreaks globally published from January 2020 to July 2021 and compiled information on hypothesized risk factors. We utilized the directed acyclic graph (DAG) to conceptualize risk mechanisms, used logistic regression to examine each risk-factor group, and further built multirisk models. RESULTS: The best-fit model showed that the intensity of community transmission (adjusted odds ratio [aOR]: 1.11, 95% CI: 1.06-1.16, for each increase of 1 case per 10 000 persons per week) and individualism (aOR: 2.72, 95% CI: 1.50-4.95, above vs. below the mean) was associated higher risk, whereas preventive measures (aOR: 0.25, 95% CI: 0.19-0.32, distancing and masking vs. none) and higher population immunity (aOR: 0.57, 95% CI: 0.46-0.71) were associated with lower risk of SARS-CoV-2 transmission in schools. Compared with students in high schools, the aOR was 0.47 (95% CI: 0.23-0.95) for students in preschools and 0.90 (95% CI: 0.76-1.08) for students in primary schools. CONCLUSIONS: Preventive measures in schools (e.g., social distancing and mask wearing) and communal efforts to lower transmission and increase vaccination uptake (i.e., vaccine-induced population immunity) in the community should be taken to collectively reduce transmission and protect children in schools.

The Structural Differences between SARS-CoV-2 and SARS-CoV-1 Spike Proteins

COVID-19 is a highly infectious disease that mainly affects the human respiratory system. Since its emergence, SARS-CoV-2 has resulted in over 86.7 million cases and over 1.87 million deaths worldwide (WHO Coronavirus Disease (COVID-19) Dashboard). Coronavirus spike glycoproteins assist in entry and infection of cells by binding to the human ACE2 receptor. Because of this, they are the main target for antibodies and inhibitors (Walls et al., 2020). There are many different strains of coronavirus, including SARS-CoV-1 and SARS-CoV-2. Although these are both ?-coronaviruses that bind to the ACE2 receptor through a spike protein, SARS-CoV-2 has been found to be less deadly but more easily transmissible than SARS-CoV-1 (Fani et al., 2020). We hypothesized that the variations in the structure of the spike proteins in different strains cause these different characteristics. In order to understand the structural differences between SARS-CoV-2 and SARS-CoV-1 spike proteins, we compared their structures by aligning them using PyMOL, a molecular visualization system. We observed that the receptor binding domain (RBD) of the spike proteins have differences in their structure. We will study these to identify their significance. The structure of a protein is directly related to its function which is why we think that this investigation is crucial to understanding COVID-19. We expect that these regions are important for specific drug targets for SARS-CoV-2.