The newest strain of New Crown is called the Omicron strain, which is more transmissible and more insidious, but less pathogenic than the Delta variant. The omicron strain has a large number of mutation sites, which makes it more transmissible and more insidious than strains such as Delta. Omicron strains tend to infect the upper respiratory tract and are therefore more likely to be transmitted via the respiratory tract. The omicron strain is less pathogenic than delta in people who have received the full course of the new crown vaccine. The Omicron variant strain mainly infects the upper respiratory tract and causes less damage to the lower respiratory tract and lung tissues, which makes it less pathogenic than the Delta variant strain, but still should not be ignored. According to the relevant scientific research, the number of patients with severe illnesses after infection with omicron in previously infected and vaccinated persons with the new crown vaccine was significantly lower than that of the Delta variant.