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COVID-19 is an acute respiratory infectious disease caused by SARS-CoV-2. It was first reported in Wuhan, China in December 2019 and rapidly spread globally in early 2020, triggering a global pandemic. In December 2022, China adjusted the dynamic COVID-zero strategy that lasted for three years. The number of positive cases in China increased rapidly in the short term. Weihai was also affected during this period. We conducted genomic surveillance of SARS-CoV-2 variants in Weihai during this period, hoping to understand the changes in the genomic characteristics of SARS-CoV-2 before and after the adjustment of the epidemic policy. In this study,we collected SARS-CoV-2 positive samples from March 2022 to March 2023 in Weihai and performed SARS-CoV-2 whole genome sequencing on these samples using next-generation sequencing technology. we obtained a total of 704 SARS-CoV-2 whole genome sequences, and selected 581 high-quality sequences for further analysis. The analysis results showed that from March 2022 to November 2022, before the adjustment of epidemic policy, the COVID-19 cases in Weihai were mainly from four local clusters,which were caused by four variants, including BA.2,BA.1.1,P.1.15 and BA.5.2.1. Phylogenetic analysis showed that: In the same cluster,the sequences between each other were highly homologous, and the whole genome sequence were almost identical. After December 2022, the epidemic policy was adjusted, BF.7 and BA.5.2 became the dominant variants in Weihai, consistent with the main domestic strains in China during the same period. Phylodynamic analysis showed that BF.7 and BA.5.2 had a large amount of genetic diversities in December, and the effective population size of BF.7 and BA.5.2 also showed explosive growth in December. In conclusion, we reported the composition and dynamic trend of SARS-CoV-2 variants in Weihai from March 2022 to March 2023. We found that there have been significant changes in the variants and expansion patterns of SARS-CoV-2 before and after the adjustment of epidemic policies. But the dominant variants in Weihai were the same as the SARS-CoV-2 variants circulating globally at the same time and we found no persistently dominant variants or new lineages during this period., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Li, Zhang, Zhang, Sui, Qu, Wang, Miao and Li.)

The global spread of the new coronavirus COVID-19 has seriously affected human health and has caused a large number of deaths. Using molecular dynamics (MD) simulations to study the microscopic dynamic behavior of the virion provides an important means to study the pathogenic mechanism. In this work, we develop an ultra-coarse-grained (UCG) model of the SARS-CoV-2 virion from the authentic cryo-electron microscopy data, which enables MD simulation of the entire virion within microseconds. In addition, a hybrid all-atom and UCG (AA/UCG) virion model involving an all-atom spike protein is developed for the investigation of the spike protein interactions. A comparison of the conformational changes for the spike proteins as simulated in the hybrid model and that isolated in solution as in the free form reveals that the former is completely different from the latter. The simulation results demonstrate the necessity for the development of multiscale models to study the functions of proteins in the biomolecular complexes.

We present the finding of a dimeric ACE2 peptide mimetic designed through side chain cross-linking and covalent dimerization. It has a binding affinity of 16 nM for the SARS-CoV-2 spike RBD, and effectively inhibits the SARS-CoV-2 pseudovirus in Huh7-hACE2 cells with an IC 50 of 190 nM and neutralizes the authentic SARS-CoV-2 in Caco2 cells with an IC 50 of 2.4 μM. Our study should provide a new insight for the optimization of peptide-based anti-SARS-CoV-2 inhibitors.

The urgent approval of the use of the inactivated COVID-19 vaccine is essential to reduce the threat and burden of the epidemic on global public health, however, our current understanding of the host immune response to inactivated vaccine remains limited. Herein, we performed serum IgG antibody detection and transcriptomics analysis on 20 SARS-CoV-2 naïve individuals who received multiple doses of inactivated vaccine and 5 SARS-CoV-2 recovered individuals who received single dose of inactivated vaccine. Our research revealed the important role of many innate immune pathways after vaccination, identified a significant correlation with the third dose of booster vaccine and proteasome-related genes, and found that SARS-CoV-2 recovered individuals can produces a strong immune response to a single dose of inactivated vaccine. These results help us understand the reaction mechanism of the host's molecular immune system to the inactivated vaccine, and provide a basis for the choice of vaccination strategy., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Zhang, Guo, Li, Kou, Lin, Yao, Pang, Zhang, Duan, Tian, Xing and Jiang.)

Background: The emergence of COVID-19 has become a global health emergency. The transmissibility of the disease is of great interest to healthcare workers and scientists alike. The primary route of transmission is via respiratory droplets, but viral RNA has also been found in feces and body fluids such as urine, serum, and semen. So far, there has been no report on whether SARS-CoV-2 is present in the exudates of cutaneous lesions. This study was designed to investigate whether SARS-CoV-2 can be found in the pressure injury exudates in patients with severe COVID-19 infections., Methods: 46 critically ill COVID-19 patients who were admitted to the ICU of the Sino-French New City Branch of Tongji Hospital in Wuhan between February 4 and April 12 developed pressure injuries. 22 patients with pressure injuries had wound exudates. Wound and pharyngeal swabs of the 22 patients were collected and RT-PCRs were conducted to detect SARS-CoV-2 viral RNA., Results: At the time of pressure injury, 5 patients still tested positive by pharyngeal swabs, the rest of the 17 patients tested negative. However, none of the wound exudate swabs from the participants tested positive for SARS-CoV-2 by RT-PCR., Conclusion: Our study suggests that it is rather unlikely that COVID-19 can be transmitted via pressure injury exudates, but we still recommend standardized personal protective equipment, face shield and an additional pair of gloves when treating pressure injuries., (© 2020 Wiley Periodicals LLC.)