A previous case of neococcal pneumonia can be detected if a secondary infection occurs. There is a risk of secondary infections after the cure of neococcal pneumonia. After a viral infection, the body produces a certain amount of antibodies that protect the body. However, antibodies remain in the body for a short period of time and do not guarantee lifelong immunity from infection. In addition, patients infected with the new coronavirus for the first time will produce specific antibodies. However, the new coronavirus is unstable and prone to mutation. Once it is attacked by other mutated viruses, the antibodies will not be able to recognize and defend against the mutated antibodies, and re-infection may occur. Patients who are re-infected can be checked for positive results by nucleic acid tests, etc. Therefore, after being cured of a previous case of neococcal pneumonia, protection should still be taken. Once the test result is positive, the patient should be isolated immediately and given targeted treatment by a doctor. Tip: In this article, the terms “neocoronavirus pneumonia” and “new coronavirus pneumonia” were renamed to “new coronavirus infection” on December 26, 2022, as announced by the National Health Commission.