The virulent strain, Omicron, is characterized primarily by strong transmission and stealth. 1. Strong concealment: it is currently believed that the incubation period of the virulent strain of omicron remains 1 to 14 days, usually 3 to 7 days, and is most contagious within 5 days of the onset of the disease, that is to say, before and after the onset of the disease, patients infected with omicron have a high degree of contagiousness, but the pathogenicity of the disease is weaker. Many patients infected with omikron are asymptomatic due to vaccinations and personal physical factors, and this group remains contagious, which results in omikron being highly susceptible to insidious transmission. 2. Strong propagation: After being infected with the Omicron variant, the patient’s symptoms are relatively mild, mainly manifested as fever, dry cough, sore throat, headache, fatigue, nasal congestion, etc. These symptoms may be more similar to those of a cold, which leads to the infected person not being easy to be detected in time. Mild cases make the virus more insidious and more difficult to recognize quickly. Such people staying at home often leads directly to the spread of the student family, and only when the disease worsens do they go to the hospital and are found, by which time the virus may have infected a lot of people, which shows that it is more spreadable.