The latest severe acute respiratory syndrome coronavirus 2 ( SARS-CoV-2) variant Omicron ( B. 1. 1. 529) has incited panic responses around the world owing to its higher level of contagiousness and vaccine-escape mutations. The susceptibility of potential hosts to the SARS-CoV-2 mutant and the antibody resistance of this virus are determined mainly by the mutation in the receptor-binding domain (RBD) of its spike (S) protein. However, a complete experimental evaluation of Omicron may take weeks or even months. Here, we analyze the infectivity, vaccine strategy, and serum antibody neutralization activity of Omicron, the result of which are expected to provide a basis for scientifically understanding the key characteristics of the Omicron mutant as soon as possible and for formulating appropriate long-term countermeasures against SARS-CoV-2.