The fact that the new crown has not turned negative means that the patient still has the new crown virus in his body, virus mutation, low immunity, etc., and needs to be isolated for observation and continued treatment. 1. New coronary virus still exists: because the new coronary virus can be transmitted through the respiratory droplet infection, so when the new coronary patients have not been negative, it means that the new coronary virus in the patient’s body continues to replicate and proliferate, and should be isolated in time for observation, to avoid cross-infection. 2. Virus mutation: the new crown has not been negative, but also may be due to virus mutation, such as Delta strain, Omicron strain, the virus load, short incubation period, so the nucleic acid turn negative time will be gradually extended, when the new crown patients have not been negative, should be timely nucleic acid test as soon as possible to the relevant departments for testing, to clarify the cause of the disease. 3. low immunity: when the patient long-term immunity is low, may lead to the new crown virus continues to replicate and proliferate in the patient’s body, so there is a persistent non-transformation of the situation. The patient should eat a balanced diet, exercise appropriately to strengthen his resistance, and take the nucleic acid test on time to observe whether the virus is negative or not. Patients who do not turn negative should undergo systematic treatment under the guidance of a doctor.