After the novel coronavirus infection is cured and the nucleic acid test is negative, the virus is not carried in the body and cannot infect others. It is important to note that the novel coronavirus is constantly mutating and may re-infect people who have been infected and are exposed to a mutated strain of the virus, so extra precautions should be taken. Lung infections caused by the novel coronavirus are often characterized by acute respiratory tract infections, with fever, dry cough, and fatigue as the main symptoms. Occasionally, symptoms such as nasal congestion, runny nose, sore throat and diarrhea can be seen. Some patients have mild fatigue and low-grade fever as the main manifestations, without the manifestation of pneumonia. It is important to take precautions in daily life, wear masks, wash hands diligently, get vaccinated, try not to go to places where people gather, respond to the call of the state, and actively cooperate with the local epidemic prevention policy. If you find a positive nucleic acid test result, or if you find yourself as a confidential person, you should report to the police in time, stay put and wait for medical personnel to come to your home to give you quarantine treatment.