Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant was first detected in Botswana and subsequently led to a worldwide surge in infections. Until now, Omicron and its lineages, the most highly mutated strains among variants of concern (VOC), have contained at least 50 mutations in the entire genome. Mutations give the virus certain adaptive advantages, such as the enhanced affinity between receptor binding domain (RBD) and human angiotensin-converting enzyme 2 (ACE2) receptors leading to enhanced transmission of the virus, and the weakened ability of virus replication leading to mild symptoms in patients with COVID-19. In addition, given its high environmental stability, Omicron can partially escape the host immune response induced by vaccination or prior infection, and is highly resistant tomost therapeutic antibodies.In this paper, key mutations, virological characteristics, pathogenicity, and immune escape of the Omicron variant are summarized, in order to provide scientific reference for coping with the new situation of the pandemic, as well as improving pandemic prevention and control strategy and public health measures.

Traditional microbial detection methods have difficulty meeting the needs of pathogen detection in the clinic. In recent years, metagenomic next-generation sequencing (mNGS) technology has emerged and been widely used in the diagnosis of various infectious diseases, the etiological analysis of emerging infectious diseases, the detection of drug resistance genes and the analysis of the host immune response. However, the mNGS workflow is complicated, and the variation introduced in each step will influence the accuracy of the detection results. In addition, the absence of standardized methods, the lack of personnel knowledge and ability, and the high cost of instruments and reagents are also creating main obstacles to the clinical application of mNGS. Therefore, standardization and normalization of methods as well as improvement of personnel knowledge and ability are urgently needed for mNGS detection. The integration of pathogen, transcriptome and antibiotic resistance genes information to comprehensively improve the clinical management of patients with infectious diseases is an important direction of mNGS detection.