If the new crown virus is negative, it is generally not contagious. At present, China’s control of the new crown patients is very strict, lifting the quarantine to meet the centralized isolation for 14 days, and the interval of more than 24 hours at least 2 times the nucleic acid test negative can be. So after strict treatment and turn negative, release quarantine patients generally will not infect people. Patients with novel coronavirus infection are not contagious when the virus is completely cleared after treatment. Some patients with novel coronavirus pneumonia who show improvement in clinical symptoms but still have positive nucleic acid test are contagious and should be closely monitored. There are also some patients who are infected by the new coronavirus did not develop disease, known as the virus carries the asymptomatic infected, although asymptomatic, but also can discharge the virus, is infectious. Patients who are released from isolation should also be protected to prevent re-infection. Prevention of new coronavirus pneumonia infection, need to wear a mask with diligent hand washing, usually more exercise, improve the body’s immunity. Tip: “New coronavirus pneumonia” and “new coronavirus pneumonia” mentioned in this article were renamed to “new coronavirus infection” on December 26, 2022, as announced by the National Health Commission.