Conversion generally means that the nucleic acid test result of the new coronavirus has turned negative, and there is still a possibility of being infected with the new coronavirus after the nucleic acid test result has turned negative. After the new coronavirus invades the human body, as an antigen, it will stimulate the body’s immune system to produce antibodies, and after the patient turns negative, it means that the virus nucleic acid has turned negative, and there is no new coronavirus in the body. After the patient is cured, there are antibodies in the body, which will gradually decrease with time. Re-infection after cure may be due to the undetected presence of the new coronavirus in the patient’s body. Moreover, the new coronavirus is an RNA virus, which is very susceptible to mutation during replication, and it may be infected again after exposure to the new coronavirus. Antibodies in the body are less effective against the mutated coronavirus, so patients should take good personal precautions after treatment and seek medical attention if abnormal symptoms occur.