1. According to the relevant public information, the virus strain in Shaoyang City belongs to the evolutionary branch of Omicron mutant ba.5.2. According to experts, the evolutionary branch of Omicron mutant Ba.5.2 has the characteristics of fast spread, strong concealment and strong infectivity. The incubation period and generation interval are short.

2. It coincides with the epidemic peak and high incidence season of respiratory diseases such as influenza in COVID-19. In addition, with the approach of the Spring Festival, the mobility of people and the increase of gathering activities, especially indoor activities, further increase the risk of epidemic spread, especially reinfection.