Nucleic acid is done every day because the new coronavirus spreads quickly and insidiously, in order to more closely detect the status of the virus infection and prevent the virus from expanding and spreading. First of all, most of the epidemic infections are Omicron variant infections, fast transmission speed, invisibility, patients with mild or asymptomatic infections, the virus can easily spread among the population, the mode of transmission is more insidious. In order to prevent exacerbation of the infection, it is necessary to do nucleic acid screening every day, and to isolate and treat infected patients in a timely manner. In addition, there is usually a certain incubation period after infection with the new coronavirus, from infection with the new coronavirus to be able to detect the virus there will be a window period, the virus is not easy to be detected, and this may lead to omission of detection. In summary, daily nucleic acid testing in heavily infected areas is necessary and is an essential means of surveillance and protection.